Prenatal Development

 

Prenatal Development and Newborn Baby

Pregnancy typically lasts about 280 days, which is often referred to as nine months. Physical development begins immediately after conception, and the pace of this development during pregnancy is faster than in other life stages. A favorable environment is crucial for the healthy development of the child during this time. If the environment is not conducive, it can adversely affect the health and life of the fetus. It is important to note that a fetus does not automatically guarantee a healthy birth; a supportive environment is essential. According to Carmichael (2000), pregnancy can last from a minimum of 180 days to a maximum of 334 days, with the average duration being around 38 weeks. Numerous changes occur during this period, which can be divided into three major stages of development (Moort and Persaud, 1998; Nilsson and Hamberger, 1990):

1. Period of the Zygote
2. Period of the Embryo
3. Period of the Fetus

Major stages of Gestational Development:

Condition	Duration	Main Event
Zygote	0-2 weeks	Week 1: The process of cell division starts in the zygote.
		Week 2: The zygote attaches to the wall of the uterus, and the structures that nourish and protect it begin to develop.
Embryo	3-4 weeks	The brain, heart, muscles, ribs, spine, and digestive system begin to develop.
	5-8 weeks	The external structure of the body (face, hands, feet, toes, fingers) and internal organs begin to form. The embryo can move.
Fetus	9-12 weeks	There is a rapid increase in size. The nervous system, organs, and muscles get organized. New behavioral abilities (kicking, sucking thumb, opening mouth, etc.) start appearing. The development of the child's sexual organs begins.
	13-24 weeks	The fetus continues to grow rapidly. During this period, the baby's movements can be felt. The fetus begins to react to sound, and its eyes become sensitive to light.
	25-38 weeks	There is a high probability of the fetus surviving after being born. Brain development takes place rapidly. Lungs mature. Antibodies reach the fetus from the mother. A layer of fat forms under the skin. By the end of this period, the fetus is ready for birth.
Neonate	0-28 days post-birth	The newborn undergoes rapid physiological changes, adapts to life outside the womb, and begins bonding with caregivers.

Period of the Zygote

The zygote stage, also known as the germinal period, lasts approximately two weeks from conception. During this time, the fertilized egg, or zygote, is about the size of a pinhead, and there is minimal change in its size. The process of cell division begins, accelerating around the fourth day. Between days seven and nine, the zygote attaches to the uterine wall, a process known as implantation, allowing it to receive nutrients from the mother's blood.

From weeks five to eight of pregnancy, significant growth occurs. Features such as the eyes, nose, ears, mouth, and neck begin to develop. At this stage, the head is disproportionately large compared to the rest of the body, with only one nostril present, and the mouth lacks a chin. The limbs are still weak, consisting of cartilage rather than bones. The internal organs become more defined; the intestines grow in size, and distinct chambers form in the heart, with the liver and spleen starting blood production. The embryo reaches about one inch in length and weighs approximately 1/7 ounce. A study by Nilsson and Hamberger (1990) found that the embryo starts to react to touch, particularly on the mouth and feet, and begins moving, although the mother cannot yet feel these movements.

Several factors can contribute to miscarriage during this stage, including emotional stress, inadequate maternal nutrition, and hormonal imbalances. A miscarriage that occurs spontaneously is referred to as a spontaneous abortion. Any obstructions during this stage can lead to developmental deformities, as this is when various organs begin to form. Therefore, pregnant women should protect themselves from stress, poor nutrition, falls, and physical weakness.

Period of the Fetus

This stage begins at the start of the third month (around the 9th week) and continues until birth. It is the longest stage of prenatal development and focuses on the growth and refinement of body parts formed during the embryonic stage. Between the 9th and 12th weeks, the fetus begins to kick, fold its hands, close its fists, open its mouth, and suck its thumb. The lungs start functioning, and by the end of the 12th week, sexual organs begin to develop, allowing for the detection of the fetus's sex via ultrasound. The external genitals, toenails, and eyelashes also develop during this period. By the end of the third month, the fetus weighs about 3/4 ounce and measures approximately 3.5 inches in length. The kidneys also begin functioning by this time. According to Martin (P.C. Martin, 1989), the region of the brain responsible for motor functions develops rapidly during this stage.

From the fourth to the sixth month (weeks 13 to 24), the mother begins to feel fetal movements. During this period, a protective white substance called vernix forms on the skin, preventing it from cracking. Fine, hair-like structures known as lanugo develop, helping to keep the vernix in place. By the 24th week, many body parts and the brain are well developed. The fetus starts responding to sound, and its eyes become sensitive to light. Despite significant development, if the fetus is born during this period, it is unlikely to survive due to underdeveloped lungs and brain systems that regulate respiration and body temperature (Berk, 2010). By the end of this stage, the fetus is approximately 12 inches long and weighs about 1-8 pounds.

If a fetus is born between the 25th and 38th weeks, survival chances increase. However, artificial respiration may be necessary immediately after birth, as the lungs are not yet mature enough to support independent breathing. By the end of the eighth month, the fetus measures about 16-18 inches and weighs between 4-5 pounds. At seven months, the head is about half the size of the body. Between the seventh and ninth months, body development accelerates compared to head growth. The skin initially appears wrinkled but becomes red by the end of this period. The hair on the skin is soft, and significant changes occur in the torso. A study by DiPietro et al. (1996) observed that the brain region controlling intellectual abilities develops rapidly during this time. Additionally, by the 28th week, the fetus begins to stay awake longer, with wakefulness increasing to 16% by the 38th week.

Studies conducted on fetuses during the seventh to ninth months (DiPietro et al., 1996; D'Agostino and Clifford, 1998) have suggested that personality traits begin to emerge. It was noted that babies who exhibit less movement during this period tend to be calmer after birth, while those who are more active may be hyperactive and irregular in sleeping and eating patterns. The fetus also starts to react to sounds and recognizes the mother’s voice. A study by DeCasper and Spence (1996) found that stories told by the mother in the last six weeks of pregnancy prompted a stronger response from the baby after birth.

It is difficult to determine the exact extent of sensory organ development at this stage, but the development of the eyes begins as early as the second or third week of pregnancy.

---

Adult Development and the Newborn

By around eight months of gestation, the arrangement of the retina in the fetus becomes almost identical to that of an adult. Throughout pregnancy, the baby remains partially deaf due to the closed state of its ears. Even after birth, the child continues to experience some degree of hearing impairment until the Eustachian tubes open and the fluid in the middle ear drains, allowing for clearer hearing. Bernard and his colleagues (Bernard et al., 1987) conducted experiments demonstrating that if a loud sound, such as a bell, is made while a special plate is placed on the nose and stomach, the fetus can respond to the sound by the ninth month.

The sense of touch develops first in the areas of the nose and mouth before spreading to other parts of the body. While the fetus is sensitive to heat and pain, its response to cold stimuli is less pronounced. By the end of this stage, the olfactory organs are well developed; however, olfactory sensation cannot occur until the nasal passages are filled with air.

The risk of miscarriage remains until about the fifth month of pregnancy, but this risk diminishes significantly thereafter. By the beginning of the eighth month, the fetus's physical, mental, and internal organs are sufficiently developed that survival is possible if the baby is born at this stage. By the end of the ninth month, the average baby measures approximately 20 inches in length and weighs between 7 and 8 pounds. In the eighth month, the fetus receives antibodies from the mother, which help protect it from diseases after birth. By the 38th week, at the end of the ninth month, the fetus prepares for birth, with its head positioned downward and legs upward, while overall growth begins to slow.

Fetal Activities

"Fetal activities" refer to the spontaneous movements of the fetus's hands and legs. By the end of the third lunar month, the fetus's muscles develop sufficiently for these spontaneous movements to begin. A study by C. E. Walters (1985) observed that the type and quantity of movements vary significantly among different fetuses. Some fetuses exhibit movements only 5% of the time, while others are active up to 75% of the time. Some fetuses may move continuously, while others show movements primarily in their arms and legs.

From the sixth to the ninth month, fetal movements generally increase, but little change occurs in the tenth month. This is primarily due to the relative increase in head weight during this period. Early in pregnancy, fetal activity tends to be more pronounced in the head region, gradually shifting to the limbs. A study by D. B. Harris and E. S. Harris (1986) indicated that the more fatigued the mother feels, the more active the fetus tends to be, with movements being more frequent in the evening than in the morning. While the frequency of movements tends to decrease in the later months, their duration increases. Additionally, sudden emotions such as anger or fear in the mother can lead to increased fetal movement.

Walters (1987) noted that fetuses who are more active during gestation tend to develop motor functions more rapidly after birth compared to those who are less active. Furthermore, these active fetuses are often smaller and thinner at birth, but they adapt more quickly to the postnatal environment and face fewer adjustment difficulties.

Fetal activities can be classified into two main types:

1. Generalized Movements: Also known as mass activity, these movements involve the entire body and begin as early as the third lunar month. Initially, these movements are responses to specific stimuli, but they become more automatic by the fifth lunar month.

2. Specific Reflexes: These movements begin to appear during the fourth to fifth month of gestation.

---

Factors Influencing the Prenatal Environment

The prenatal environment is distinct from the external environment and is relatively constant. However, several factors can influence the developing embryo and fetus. These factors include:

1. Effect of Prescribed Drugs

While many drugs are prescribed to pregnant women, their consumption can adversely affect the pregnancy environment and the unborn child. For instance, in the 1960s, the sedative drug Thalidomide was widely used, but studies (Moore & Persaud, 1998) showed that its intake by pregnant women during weeks 4 to 6 resulted in severe deformities in the fetus's hands and feet, as well as damage to the eyes, heart, and kidneys. Approximately 7,000 unborn babies worldwide were affected, and many showed lower-than-normal intellectual levels later in life due to potential impacts on their central nervous systems.

Another example is Diethylstilbestrol (DES), which was commonly prescribed between 1945 and 1970 to prevent miscarriage. Later, girls exposed to DES during pregnancy showed a higher incidence of vaginal cancer and uterine abnormalities, while boys were found to have an increased risk of testicular cancer (Glusti, Iwamoto, & Hatch, 1995; Palmlund, 1996).

Further studies (Barr et al., 1990; Hauth et al., 1995; Streissguth et al., 1997) indicated that the continuous intake of Aspirin was linked to fetal death at birth, low birth weight, and developmental issues. Given the potential risks, the safest approach is to avoid or minimize medication consumption during pregnancy.

2. Effect of Illegal Drugs

Illegal substances such as cocaine, heroin, and marijuana can have severe adverse effects on unborn children. Studies (Johnson & Rosen, 1998; Walker et al., 1999) indicate that children born to mothers addicted to these substances face numerous challenges, including premature delivery and low birth weight. Research (Espy, Kaufmann, & Glisky, 1999; Mayes, 1999; Plessinger & Woods, 1998) shows that cocaine exposure can impair brain development, leading to long-term issues related to bones, reproductive organs, kidneys, motor skills, vision, attention, memory, and language (Mayes, 2000).

Marijuana, which is more commonly used than heroin and cocaine, has been found to cause premature births and lower birth weights. Studies (Dahl et al., 1995; Fried, Watkinson, & Gray, 1999; Lester & Dreher, 1989) report that marijuana exposure is associated with smaller head sizes, sleep difficulties, distractibility, and heightened startle responses in newborns.

The mixed effects of illicit drugs on the prenatal environment make it challenging to determine the specific impact of each drug. Additionally, mothers addicted to these substances may exhibit behavioral problems that hinder their ability to care for their children, further affecting the child's development (Lester, 2000; Alessandri, Bendersky, & Lewis, 1998; Carta et al., 2001).

3. Effect of Tobacco

Smoking during pregnancy is linked to several negative outcomes, the most common being low birth weight. Studies (Franco et al., 2000; Walker, Balaban-Gil, 1999) reveal that smoking has serious side effects, including miscarriage, premature birth, impaired sleep breathing, and increased cancer risk in childhood. Research (Cornelius et al., 2001; Trasti et al., 1999; Wasserman et al., 2001) indicates that children born to mothers who smoke often experience attention deficits, memory issues, and behavioral problems during childhood and adolescence.

Nicotine in tobacco constricts blood vessels, reducing blood flow to the uterus and depriving the fetus of essential nutrients, which can slow its development. Carbon monoxide from tobacco smoke further decreases oxygen levels in the blood of both the mother and fetus, negatively affecting the fetal central nervous system (Friedman, 1996). Therefore, pregnant women should avoid tobacco consumption to mitigate these harmful effects.

4. Effect of Alcohol

Alcohol consumption during pregnancy can lead to severe developmental issues known as Fetal Alcohol Syndrome (FAS). Children born with FAS may experience mental retardation, impaired motor coordination, and cognitive and language difficulties (Cornor et al., 2001; Schonfeld et al., 2001). These children often display distinct facial features, such as widely spaced eyes, small eyelid openings, a flat nose, a thin upper lip, and a smaller head, indicating incomplete brain development.

Even with adequate nutrition, children with FAS may experience slow physical development and lasting intellectual deficits, leading to decision-making challenges and lower performance on intellectual and achievement tests. Such children are also at a higher risk for developing alcohol dependency and mental health issues during adolescence (Aronson et al., 1997; Hunt et al., 1995; Kelly, Day, & Streissguth, 2000).

Alcohol affects the prenatal environment in two significant ways: (1) It hinders the mental development of the fetus, leading to brain function abnormalities; and (2) It increases the mother's oxygen demand, which, when unmet, deprives the fetus of sufficient oxygen for cell growth (Bookstein, 2002). Studies (Day et al., 2002; Astley, 1992) have shown that even minimal alcohol consumption (e.g., 50 ml per day) can negatively impact fetal development, leading to reduced head size, physical growth, and facial deformities. Consequently, it is advisable for pregnant women to completely abstain from alcohol.

5) Effect of Infectious Disease

Infectious diseases contracted during pregnancy, such as measles, chickenpox, AIDS, herpes, and parasitic diseases, can negatively impact the physical and mental development of the child. For instance, if a mother contracts measles during the embryonic stage, there is a high likelihood of the child experiencing heart defects, cataracts, deafness, and sexual deformities. Infection during the fetal period can result in low birth weight, reduced hearing ability, and bone defects (Eberhart et al., 1993; Lec et al., 1992; Pebody et al., 2000).

In cases of AIDS, bone defects can also occur (Eberhart et al., 1993; Lec et al., 1992; Pebody et al., 2000). If a pregnant woman has AIDS, the HIV virus can be transmitted to the developing fetus. The progression of AIDS in fetuses and newborns is rapid, with those affected typically surviving only five to eight months (Park, 1996). However, a study (Culnane et al., 1999) indicated that the use of antiviral drugs during pregnancy can prevent the transmission of AIDS to the fetus by 95%.

The developing fetus is particularly vulnerable to the herpes virus, for which no cure or vaccine exists. Research (Behrman, Kliegman, and Jenson, 2000) shows that fetuses affected by the herpes virus may either be aborted or born with low birth weight, physical weaknesses, and mental retardation.

Many bacterial and parasitic diseases can also harm the fetus during the prenatal period. Toxoplasmosis, a common parasitic disease, can affect pregnant women who consume undercooked or raw meat. If the mother contracts this disease before the fetal stage, it can lead to eye and brain damage in the fetus. If contracted after this stage, it may result in visual and cognitive impairments (Jones et al., 2000).

6) Effect of Environmental Pollution

In industrialized countries, many hazardous chemicals are released into the atmosphere as pollutants. Mercury is one such chemical known to harm the fetus by affecting the pregnancy environment. Industrial factories often release waste containing high levels of mercury, which can contaminate food and drinking water. Continuous consumption of mercury-contaminated food and water by pregnant women can lead to various physical and mental defects in their children. A study (Dietrich, 1999) revealed that children exposed to mercury during pregnancy may experience physical deformities, mental retardation, abnormal speech, and difficulties in swallowing and chewing after birth.

Lead, another environmental pollutant, can also severely affect fetal development. It is found in paint and some factory materials. High levels of lead exposure during pregnancy can result in premature birth, low birth weight, brain damage, and various physical defects (Day-White, 1986). Additional studies (Dietrich et al., 1993; Wasserman et al., 1994) have shown that even low lead levels during pregnancy can slow the mental and physical development of affected babies.

Other environmental pollutants present in water and food can also significantly harm the fetus. Research (Chen et al., 1994; Stewart, 2000; Jacobson, 1998; Jacobson et al., 2001) indicates that infants born to mothers exposed to environmental pollution may suffer from numerous defects, including blotchy skin, nail and gum deformities, brain connection abnormalities, delayed cognitive development, smaller head size, lower birth weight, and memory problems.

7) Effect of Radiation

Tragically, numerous defects were observed in pregnant women exposed to radiation during the atomic bomb attacks on Hiroshima and Nagasaki during World War II. Similar abnormalities occurred after the 1986 nuclear power plant accident in Ukraine. Following each of these disasters, cases of miscarriage and children born with underdeveloped brains, physical defects, and slow growth were reported (Schull and Otake, 1999; Burtzeva, 1991).

Even minimal exposure to radiation can lead to delayed problems, with infants appearing normal at birth but later developing issues. For instance, X-rays taken during pregnancy increase the risk of childhood cancer (Fattibene et al., 1999). Infants exposed to radiation during pregnancy are two to three times more likely to experience language and emotional disorders compared to those not exposed. The harmful effects of radiation, compounded by the mother's stressful conditions, can hinder the child's development at birth.

8) Maternal Nutrition

During pregnancy, the fetus relies entirely on the mother for nourishment through the placenta. Thus, it is essential for the mother's diet to be balanced and contain all necessary nutrients. Appropriate amounts of proteins, fats, and carbohydrates are crucial; proteins help form tissues, fats provide energy, and carbohydrates supply strength. Some pregnant women mistakenly believe they need to "eat for two," which can lead to obesity in the fetus and complications during birth. A balanced diet is vital for normal fetal development.

A study by Hepner (1988) found that an unbalanced diet in pregnant women can lead to various defects in the unborn child. These defects may include mental weakness, physical abnormalities, general frailty, nervous instability, and epilepsy. A deficiency of vitamin A in the mother's diet can cause eye deformities in the newborn, while a lack of vitamin D can result in dental and bone issues. Research has shown that continuous vitamin B deficiency during pregnancy can lead to lower intelligence in the newborn, with subsequent learning difficulties in school. Women who restrict their food intake to avoid gaining weight may significantly impact their fetus's development.

Another study (Morgane et al., 1993) noted that malnutrition during pregnancy could damage the fetus's central nervous system. Poor maternal nutrition in the last three months of pregnancy, when the brain grows rapidly, results in lower brain weight in the fetus. Furthermore, Baker (1994) found that inadequate maternal nutrition could deform the fetus's pancreas, liver, and blood vessels, leading to lifelong health issues. Chandra (1991) discovered that babies lacking a balanced diet during pregnancy have weakened immune systems and are more susceptible to respiratory diseases.

9) Maternal Health

Studies have demonstrated that the health of pregnant women significantly impacts fetal development. Serious diseases like syphilis or gonorrhea can have detrimental effects on the fetus. For example, these diseases may lead to miscarriage or, if the pregnancy continues, the child may be born blind, deaf, mentally challenged, or with other motor disorders.

Excessive use of quinine (for malaria and other conditions) during pregnancy can affect the child's hearing, leading to deafness. Additionally, pregnant women frequently take medications for headaches or body pain, which can compromise oxygen supply to the fetus's brain, potentially causing brain damage (Montagu, 1982; Taussing, 1992). Disorders in the pregnant woman’s endocrine glands can also lead to developmental abnormalities in the fetus, resulting in conditions like cretinism, hydrocephalus, or mongoloid idiocy.

10) Maternal Emotional Stress

A pregnant woman's emotional state significantly influences fetal development. Women unhappy with their pregnancies often experience nausea or vomiting and may resort to medications to attempt an abortion. When such attempts fail, it can result in physical and mental disorders in the fetus. A study (P.H. Gebhard et al., 1988) found that prolonged high emotional stress in early pregnancy can lead to serious developmental consequences for the fetus, including physical and mental defects.

Research (Cohen and Williamson, 1991; Monk et al., 2000; Carmichael and Shaw, 2000) indicates that maternal fear and anxiety can elevate stress levels in the fetus. In response, the body releases stress hormones that redirect blood flow away from the uterus, depriving the fetus of oxygen and nutrients, resulting in potential mental and physical damage. Studies (Mchean, 1993; Hoffman and Hatch, 1996) also suggest that maternal stress-related issues diminish significantly when pregnant women receive support from their partners, family, and friends.

11) Maternal Age

It is generally believed that the optimal age for a woman to become pregnant is between 20 and 30 years. The risk of miscarriage increases significantly after the age of 35. Additionally, women’s fertility declines after 30. Some studies (Bianco et al., 1996; Dildy et al., 1996; Prysak et al., 1995) indicate that healthy women in their 40s can avoid pregnancy-related issues. These studies also suggest that despite physical immaturity, girls aged 13 to 17 do not typically face pregnancy problems, as nature equips them for conception once they reach reproductive capability.

The Prenatal Environment and Health in Later Life

Extensive evidence suggests that the prenatal environment significantly impacts future health outcomes. Children born prematurely or with low birth weight due to adverse environmental conditions during pregnancy are at a higher risk of developing conditions such as diabetes, high blood pressure, and stroke in adulthood. Studies indicate that even less significant factors, such as inadequate nutrition and the transfer of maternal hormones to the fetus, can affect long-term health (Wheeler and Barker, 1999).

The relationship between the prenatal environment and future health can be summarized in two key points:

1. Low Birth Weight

Children born with a weight lower than the norm are more likely to encounter health issues later in life. Research by Franco et al. (2000) demonstrates that fetuses that do not receive adequate nutrition have an elevated risk of heart disease in adulthood. Further studies (Godfrey and Barker, 2000; Martyn et al., 2001) reveal that children born three or more weeks premature and weighing less than 5 pounds have a 50% increased risk of dying from heart disease or stroke later in life. Numerous studies (Forsen et al., 2000; Eriksson, 2001; Godfrey and Barker, 2001) have shown a significant correlation between low birth weight and increased risks of heart disease, stroke, and diabetes. Individuals with low birth weights are particularly vulnerable to these conditions in middle adulthood.

Research (Barker, 2002; Osmond and Barker, 2000; Rich-Edwards et al., 1999) has found that poor nutrition during pregnancy may lead to reduced blood flow to the fetus, resulting in underdeveloped pancreatic function. This can lead to elevated cholesterol levels, increased blood pressure, and ultimately diabetes, predisposing individuals to serious health complications later in life.

2. High Birth Weight

Conversely, girls born with a higher-than-normal birth weight are more likely to develop breast cancer as adults (Anderson et al., 2001; Vatten et al., 2002). A study conducted by Michels et al. (1996) involving 589 women with breast cancer and 1,569 women without, controlled for pregnancy-related health risks. The findings indicated that women with a birth weight exceeding 8.7 pounds had a heightened risk of developing breast cancer. Additionally, pregnant women who secrete elevated levels of estrogen may give birth to larger fetuses, increasing the likelihood of breast cancer later in life. Researchers suggest that excessive estrogen secretion is a significant contributing factor to breast cancer.

While research has established a link between prenatal development and future diseases, it does not guarantee that these conditions will manifest. Environmental factors during pregnancy can pose risks to an individual’s future health. Preventative measures, such as regular medical check-ups for those with low birth weights and maintaining a healthy diet and lifestyle, can help mitigate these risks.

Newborn Baby (Neonate)

A fetus is typically born 280 days after conception. As the delivery approaches, a smooth fluid begins to exit the pregnant woman’s fallopian tube, facilitating the fetus's exit. Labor pains usually commence 10 to 16 hours before birth, with duration varying based on whether it is the mother’s first child; subsequent deliveries generally involve shorter labor.

The delivery process can occur in several ways:

• Natural or Spontaneous Birth: In this process, the child's head emerges first, followed by the torso and legs. In cases where the fetus is significantly larger than the mother's reproductive canal, the buttocks may emerge first.

• Instrument Birth: This method is used when the fetus is too large for a natural delivery, requiring specialized instruments for assistance.

• Complicated Birth (Caesarean): In this scenario, the child is delivered through an incision in the abdomen rather than the vaginal canal.

According to Montagu (1982), smoother births tend to result in better postnatal adjustments to the environment. Studies (B.J. Bolin, 1989; J.L. Boland, 1982; R. Davis, 1981) indicate that cesarean-born infants often exhibit different personality traits, such as hyperactivity, restlessness, and difficulties in concentration compared to those born naturally.

The term "neonate" originates from the Latin word neos, meaning "new," referring to a newborn child aged up to 30 days. The initial period following birth, known as partunate, is when the umbilical cord is cut, marking the child’s separation from the mother.

Key characteristics of a newborn baby include:

1. Physical Development
2. Activities of a Newborn Baby
3. Crying Patterns
4. Sensitivity
5. Emotions
6. Learning Ability
7. Personality Traits

Properties Related to Physical Development

1. Size of the Infant: The average weight of a newborn is approximately 7.5 pounds, with an average length of 19.5 inches. Weight can range from 3 to 16 pounds, and height from 15 to 21 inches. Generally, boys are taller than girls at birth. Several factors influence newborn size, including:

   • Maternal Diet: Maternal nutrition significantly affects infant size. Smith and Wines (1977) noted that inadequate maternal nutrients result in smaller newborns. A study by Burke et al. (1989) indicated that the mother's diet during the final month of pregnancy is particularly influential.

   • Economic Status: The parents' economic status impacts the quality and quantity of the mother's diet. Research by Gibson (1971) showed that lower economic status correlates with smaller and underweight infants.

   • Birth Order: According to Meredith (1950), a woman's first child is typically 1% shorter and 9% lighter than subsequent children.

   • Fetal Activity: Studies suggest that more active fetuses tend to have lower birth weights.

   • Other Factors: Newborns fed within six hours after birth often lose weight. In some studies (Brown, 1989; Salber and Bradshaw, 1983), seasonal variations have been observed, with infants in certain climates gaining weight more rapidly. Typically, a newborn loses weight for the first seven days post-birth before starting to gain.

2. Physical Proportions: Harlock (2004) emphasized that newborn proportions differ significantly from adults. The head constitutes about one-fourth of the body, while in adults, the head accounts for one-seventeenth. The newborn's neck is narrow, and its body features—such as the stomach, nose, and jaws—are underdeveloped relative to the head.

3. Infantile Features

Newborns exhibit several distinctive features that are characteristic of their early developmental stage:

• Eyes: At birth, newborns typically have light brown eyes, which darken to a more permanent shade—most commonly black—within a few days. Although their eyes may appear mature, they lack precise control and coordination, often seeming to look in different directions simultaneously.
• Neck: A newborn's neck is notably short, primarily due to the relatively larger size of the head compared to the rest of the body, making the neck appear almost non-existent.
• Hair: The hair on a newborn is soft and silky. The fine hair on the back and shoulders usually falls out within the first few weeks after birth.
• Muscles: Newborns have small, soft muscles with limited control, particularly in the legs and neck, which are less developed compared to other muscle groups.
• Bones: The bones of a newborn are flexible, soft, and primarily composed of cartilage, making them pliable during this early stage of development.
• Skin: Newborn skin is light pink at birth and typically develops a pinkish tint within about 15 days. After one day, the skin color begins to stabilize.
• Teeth: Most babies are born without teeth. However, research by Massler and Savara (1950) indicated that in America, about 1 in 2,000 babies are born with teeth, usually located in the front of the lower jaw. The presence of teeth at birth is considered a genetic anomaly.

    4. Physiological Functions

The physiological functions of newborns differ significantly from those of older children:

1. Respiration: Newborns begin crying immediately after birth, which helps expand their lungs and initiate the respiratory process (C. A. Smith, 1963). The initial respiratory rate ranges from 40 to 60 breaths per minute and stabilizes at around 35 breaths per minute by the end of the first week. In adults, the normal breathing rate is about 18 breaths per minute. While awake, a newborn typically breathes at 32-60 breaths per minute, dropping to 13-30 breaths per minute during sleep.

2. Heart Rate: Newborns have a higher heart rate compared to adults due to their smaller heart size. According to H. J. Grossman and N. H. Greenberg (1957), a higher heart rate is necessary to maintain normal blood pressure.

3. Temperature: Newborns maintain higher body temperatures than adults, with a typical range of 98.2° to 99° Fahrenheit, which is also more variable.

4. Pulse Rate: At birth, a baby’s pulse rate averages between 130 and 150 beats per minute but drops to around 77 beats per minute within a few days. In contrast, an adult's resting pulse rate is about 70 beats per minute. While sleeping, a newborn’s pulse rate is around 123 beats per minute and can rise to 218 beats per minute when crying.

5. Reflex Sucking Movements: Newborns exhibit reflexive sucking movements when their lips are touched or when they are hungry. B. Spock (1974) observed that breastfed infants show more frequent sucking movements compared to those fed with a bottle.

6. Hunger Rhythms: Newborns do not experience hunger contractions at birth; these develop around two to three weeks of age. According to Pratt (1954), a newborn's stomach empties within 4 to 5 hours, the small intestine in 7 to 8 hours, and the large intestine in 12 to 14 hours. Babies typically pass stool and urine about five times in a 24-hour period, often remaining silent during these processes (Halverson, 1940).

7. Sleep Patterns: Newborns typically sleep for 15 to 20 hours daily but do so in short intervals of about two hours at a time. As they grow older, their sleep patterns lengthen and become more regular. They awaken primarily due to hunger, discomfort, or internal needs.

---

Activities of the Newborn

The actions of a newborn are spontaneous, though many seem purposeless at first glance. These activities can be divided into two main categories:

1. Mass Activities

These involve the entire body. If any part of the newborn’s body is touched, the baby responds with full-body movements. Interestingly, when one hand is touched, the opposite hand often responds similarly. Kessen (1981) notes that these generalized responses increase significantly during the first five days of life, especially in the morning. While facial, hand, and foot movements are most common, all parts of the body are active. Studies also show that babies who were highly active in the womb tend to remain active post-birth (Sontag, 1986). Mass activity increases in response to hunger, discomfort, pain, or extreme changes in light or temperature, although slight changes in temperature have minimal impact.

2. Specific Activities

These actions can be categorized into two types:

(a) Reflexes

Reflexes are innate, automatic responses to specific stimuli, and they remain unchanged even with repeated exposure. Some key newborn reflexes include:

1. Pupillary Reflex – The pupil expands or contracts in response to changes in light, helping protect the eyes. This reflex appears within two hours of birth.
2. Babinski Reflex – When the sole of the foot is touched, the baby fans its toes. This reflex disappears around six months.
3. Tendon Reflex – Muscle contraction occurs when touched.
4. Sucking Reflex – Touching the baby’s lips or cheeks prompts sucking motions.
5. Rooting Reflex – Stroking the baby’s cheek near the mouth causes the head to turn towards the stimulus, helping the baby find the nipple. This reflex diminishes after about three weeks.
6. Moro Reflex – When startled by a sudden movement or sound, the infant throws its arms and legs outward as if reaching for something. This reflex is visible for about six months.
7. Palmar Grasp Reflex – Placing a finger in the baby’s palm causes the baby to grasp it. This reflex lasts for about four months.
8. Stepping Reflex – When held upright with feet touching a surface, the baby makes stepping motions, as though trying to walk.
9. Swimming Reflex – When placed face down in water, the baby makes swimming-like movements. This reflex is observed between four and six months.

Reflexes generally disappear by six months as the baby gains more control over their movements. The absence or persistence of these reflexes can signal potential neurological issues (Zafciriou, 2000).

(b) Generalized Responses

Generalized responses involve multiple body parts. In the first few days after birth, babies often display uncoordinated eye movements, appearing to look in two different directions. Newborns can only briefly look towards the light on their first day and sometimes even shed tears. Thumb-sucking and mouth-opening movements are also common shortly after birth. Movements of the arms and legs start immediately and continue to develop.

---

Crying of the Newborn

A newborn's crying begins at birth or shortly thereafter, marking their first form of communication. Initially, this cry is an instinctive response, crucial for their survival. The act of crying helps expand the lungs and initiates breathing, allowing oxygen to enter the bloodstream. It is the first moment when a person hears their own voice. The meaning of a baby's cries evolves within the first 24 hours, starting with distinctive sounds that are accompanied by movements of their arms and legs, and alternating between opening and closing their fists.

Crying serves as the primary means for infants to communicate their needs, such as hunger and fatigue. The intensity and pattern of their cries convey different messages to caregivers. In the weeks following birth, the baby's unique cry can be recognized even from a distance (Gustafson, Green, & Cleland, 2000). Research (Dondi, Simion, & Caltran, 1999; Barr, 2001) indicates that infants typically cry to express physical needs, respond to environmental changes (like temperature fluctuations), react to sudden loud noises, or signal discomfort. Interestingly, babies may also cry in response to the sight of another crying child.

According to Aldrich (1985), the reasons for an infant's crying can be physical or environmental, but often the cause remains unclear. Common triggers include noise, light, vomiting, overheating, discomfort during bathing, hunger, and various unknown factors. A study by Fries (1991) found that infants born via cesarean section tend to cry less than those born vaginally. Additionally, research by Karelitz et al. (1994) revealed that babies whose mothers used more medications during pregnancy or who experienced complications at birth often cry more than other infants. Graham et al. (1982, 1983) observed that babies born through natural delivery typically cry louder at birth compared to their counterparts.

---

Sensitivity of the Neonate

Studying the sensitivity of newborns presents challenges, primarily because such research often relies on introspective methods. As a result, it can be difficult to accurately assess which sensations newborns experience and to what extent. According to Gesell (1949), infants born before the completion of the gestational period respond to intense stimuli similarly to full-term infants. Tactile sensations are more frequently observed in infants than other sensory responses.

1. Sight – At birth, the retina, which houses the cells responsible for vision, is not fully developed. The cones in the fovea are particularly underdeveloped, suggesting that newborns are somewhat "color blind." However, studies show that infants begin to respond to colors by their seventh day. Smith (1996) notes that girls tend to respond more to color stimuli than boys during the first week of life. Although the number of cones and rods in the retina is comparable to that of adults, Harlock (2004) suggests that newborns can see very close objects on their first day, and by the end of the first week, they can perceive nearby stimuli. However, their eye muscles are not yet strong enough to maintain focus on any object for an extended period. A study by Waizda (2001) found that while infants can see up to 20 feet at birth, their clarity is limited. They are particularly drawn to shiny and moving objects. Research by Adams, Courage, and Mereer (1994) indicates that shortly after birth, infants are more attracted to shiny colored objects rather than black and white, although they cannot differentiate between colors.

2. Hearing – At birth, the auditory system is the least developed of all the senses. Psychologists disagree on whether newborns can hear immediately after birth. Some believe that infants begin to hear within ten minutes, while others argue that they remain completely deaf for several days. Pratt (1954) posits that newborns start responding to sound stimuli between the third and seventh days after birth. According to Leventhal and Lipsitt (1964), babies can localize sound after approximately 118 hours. A study by Bench et al. (1999) found that newborns can perceive various sounds, showing a preference for mixed sounds. Infants are particularly sensitive to human voices, which prepares them to respond to caregivers. Astin and Jusczyk (1998) observed that babies pay more attention to high-pitched and expressive voices.

3. Taste – The taste sense is more developed in newborns compared to other senses. Research has shown that infants respond positively to sweet stimuli while displaying aversion to salty, sour, and bitter tastes. Pratt (1984) notes that individual differences exist among infants regarding taste sensitivity thresholds. Studies conducted by Mennella et al. (1998) and Harris (1997) indicate that infants are attracted to sweet flavors, likely because their primary source of nutrition, mother's milk, is sweet. Over time, infants may begin to accept tastes they previously disliked, associating them with hunger.

4. Smell – Smell sensitivity is either well-developed at birth or rapidly develops within a few days. A study by Lipsitt et al. (1963) found that if a mother applies strong odors, such as vinegar or ammonia, to her breast while breastfeeding, the baby may refuse to nurse. Pratt (1984) notes that individual differences in smell sensitivity also exist. Research by Reiser (1996) observed that newborns can locate smells and tend to turn away from unpleasant odors. By the fourth day of life, infants recognize the scent of their mothers and her milk, showing a preference for breastfeeding.

5. Skin Sensitivity – Newborns exhibit sensitivity to touch, pressure, heat, and pain from birth or shortly thereafter. Certain body parts, such as the lips, are more sensitive than others. Infants tend to respond more strongly to cold stimuli than to heat. Pain perception is somewhat diminished in the first two days after birth, with heightened sensitivity found in the lips, palms, and soles of the feet, as well as in the eyelids, forehead, and nasal membranes.

Emotions of the Neonate

Research on the emotions of newborns is relatively limited, but the studies conducted provide valuable insights. According to Watson (1985), three primary emotions can be observed in infants at birth or shortly thereafter: fear, anger, and love. He suggests that specific stimuli can elicit these emotions. Bankwin (1997) further asserts that the emotional responses of newborns are highly developed, noting that similar emotional patterns can be seen in preterm infants.

Harlock (2004) argues that it may be unrealistic to expect emotional states at birth to be well-defined. Many modern psychologists believe that newborns do not experience distinct emotions; instead, they exhibit two general types of responses. The first type encompasses pleasant responses, which occur during breastfeeding or when being held comfortably. The second type consists of unpleasant responses, manifested when an infant is picked up abruptly or laid down suddenly, or when exposed to loud noises. Some researchers (K. M. Banham, 1981; R. A. Spitz, 1989) contend that unpleasant responses are more pronounced than pleasant ones.

When mothers stop breastfeeding prematurely, infants may feel deprived of maternal affection, leading to an inadequate sense of satisfaction from bottle feeding. This can hinder the natural development of the feeling of love in such children. In contemporary society, some women choose not to breastfeed due to concerns about the appearance of their breasts. However, studies indicate that breastfeeding does not harm breast shape; in fact, it can strengthen the breast and vaginal tissues.

In situations where mothers try to quiet their crying infants—perhaps to appease other family members or due to busy schedules—they may resort to threatening gestures. This approach can heighten the child's fear responses. Moreover, if a newborn is left to cry without proper attention, it may experience fear, insecurity, and despair, especially if the caregiving environment is inconsistent.

---

Capacity for Learning in Infants

Newborns have a limited capacity for learning due to their underdeveloped nervous system and brain. Conditioning, a basic form of learning, is challenging in newborns but possible, especially in feeding situations (Marquis, 1981; Pratt, 1994).

---

Personality of the Neonate

Differences in the personalities of newborns begin to emerge within just a few days after birth. While some infants are calm and easygoing, others may be more challenging for their parents. These personality variations stem not only from hereditary and environmental factors but also from circumstances surrounding birth, such as prematurity, the conditions at birth, and overall health.

Freud (1936) posited that birth is both a physiological and psychological trauma, leading to a psychological shock that can result in anxiety for the newborn. Some psychologists (H. Ruja, 1989; H. A. Carithers, 1981) contend that this birth shock does indeed impact the child's personality development. Studies have shown that children who are separated from their mothers immediately after birth and kept apart struggle more with adjustment in various situations compared to those who remain with their mothers (L. J. Yarrow, 1981).

The mother's mindset during pregnancy also plays a crucial role in shaping the child's personality. For instance, mothers may struggle to bond with a child of undesired sex, affecting the child's development. Research by Ruja (1978) found that cesarean-born infants tend to be quieter, yet they demonstrate better adjustment in different life situations.

Additionally, some studies have explored the relationship between a child's month of birth and personality traits. Pintner and Forlano (1984) observed that many talented and renowned individuals were born in October, while fewer such individuals were born in the spring. Another study (Pile, 1981; Sumner, 1993) indicated that children born in spring, summer, or autumn tend to be more social than those born in winter. Furthermore, Boland (1991) noted that infants born via instrumental delivery are often more sensitive, experiencing issues such as restlessness, language delays, and difficulties with concentration.

---

Questions

1. Describe the major milestones of pregnancy development based on scientific studies.

2. What are the primary stages of pregnancy development? Outline the main events that occur during each stage.

3. How do you define pregnancy? Discuss the developmental changes that occur during this period for the fetus.

4. What factors influence the prenatal environment? Provide a detailed description.

5. Explain, with reference to studies, the impact of drugs, alcohol, and tobacco on the pregnancy environment.

6. What maternal factors affect the child's development during pregnancy? Discuss in detail.

7. How does the prenatal environment impact health in later life? Elaborate on the potential effects.

8. How do you define a newborn? Describe its various characteristics.

9. Discuss the emotions and personality of a newborn based on psychological studies.

Short Answer Questions

10. Describe the developmental processes that occur during the zygote stage.

11. What is the embryonic period, and what changes occur within the embryo during this time?

12. List and explain the activities observed in the fetus during its development.

13. Write a note on the following:
    (a) The relationship between gestational development and infectious diseases.

Best of Luck !!