PSYC336_Chapter 3 - Prenatal Development, Birth, and the Newborn

The germinal period (first two weeks)

1. After fertilization, the zygote travels down the fallopian tubes and toward the uterus. 2. After a day or so, it begins to divide continually via mitosis. 3. Four days after fertilization, the zygote has become a ball of cells with a hollow core (blastocyst) 4. A cluster of cells inside the blastocyst develops into the embryo. The outer cells form the supporting structures that sustain the embryo 5. After making contact with the uterus, the blastocyst burrows deep into the uterine wall and becomes firmly implanted by the end of the second week after fertilization When twins come about

Prenatal brain development: four main processes

1. Neurogenesis 2. Neural migration 3. Neural differentiation 4. Formation of neural connections

Fetal period: behavior and cognitive abilities

14-20 weeks of again: enough room for the fetus to move - Wide range of movements - acrobatic movements. When they are too big, they engage in smaller movements such as smiles, frowns, pursing the lips, and sticking the tongue out - Movement is vital for physical development Movement and growth of physical structures influence each other bidirectionally The fetus develops and "practices" sensory abilities and behaviors that will be useful in adaptation to the world outside the womb By month 3: the fetus begins to swallow amniotic fluid and has primitive taste buds. The fetus is exposed to various flavors from the mother's diet - May help prepare fetuses to enjoy the mother's breast milk - Yawning, blinking, kicking, moving its arms in a coordinated fashion, sucking its thumb, breathing amniotic fluid in and out of the lungs, and crying when disturbed By 6 month: fetuses can hear and see After 7 months: fetuses begin to establish cycles of sleeping and waking that increasingly resemble the cycles of alertness in newborns Newborn: acquire the capability to nurse and to recognize their mother's voices and faces within a few hours - Fetuses can also learn to recognize particular voices and melodies and to distinguish between their native language and a foreign language

Prenatal influence

98 percent of babies are born without serious birth defects

Prenatal brain development: brain growth

25 days: the fundamental structures of the brain (forebrain, midbrain, hindbrain) develop at the end of the neural tube. 50 days: the forebrain expands and covers the midbrain. 100 days: the cortex begins to take shape and grows around the inner areas of the brain. 20 weeks: continuing growth of the cortex. The purple structures at the top of the neural tube are the brain stem and cerebellum. 28 weeks: neural migration is complete at this point. The major structures of the brain are present in primitive form. 39 weeks: the brain of a full-term baby has all of the major structures of the adult brain but will not reach mature functioning for 20 to 25 years.

Preeclampsia

5-10% of pregnancies Mother's blood pressure increases dramatically in the second or third trimester. Hospitalization, bed rest, and medications can lower blood pressure to within safe levels, but when this is ineffective, the baby must be delivered early

Sexual differentiation: external genitals

6 weeks after conception: Male and female embryos have identical external genitals that begin as a single set of structures, as shown here. Second trimester: Production of testosterone by the testes causes the top end of the structure to develop into a penis and the middle of the structure to develop into the scrotum. Birth: If testosterone is not present, the top end becomes a clitoris, and the middle becomes the inner and outer labia and the opening of the vagina

Monitoring the health of the fetus: triple screen test - positives

75 percent to 90 percent of babies with neural tube defects can be discovered

Embryonic period: neural plate defect

Defects resulting from failure of the neural tube to close Anencephaly Spina bifida One important risk factor for neural tube defects is a lack of the B-complex vitamin folic acid in the mother's die

Periods of prenantal development

Development begins with the union of sperm and ovum in the woman's fallopian tube to form the zygote 1. The germinal period (first two weeks) 2. Embryonic period (three to eight weeks) 3. Fetal period (nine weeks until birth)

Prenatal influence: drug abuse

Different drugs have different apparent effects depending on timing and dose, as illustrated in the following image.

Fraternal twins (dizygotic): commonality

Dizygotic twins are becoming more common because more women are having babies in their 30s, a time when fertility drops. Many women use fertility drugs, which stimulate the production of ova, increasing the chance of multiple births

Fetal period: lanugo

Downy hair covering a baby at 5 months

Prenatal influence: smoking - why it makes its impact

Exposure to prenatal smoke decreases methylation across a wide swath of the genome, resulting in many potential changes in gene expression. Prenatal smoke exposure increases methylation in certain genes that have been linked to cancer

Prenatal influence: alcohol - fetal alcohol spectrum disorder (FASD) commonality

FASD the most common nongenetic cause of intellectual impairment and birth defects It is more likely to occur in women who have other risk factors, particularly if they live under conditions of extreme poverty or stress.

Embryonic period: neural plate defect - spina bifida

Failures of the neural tube to close in the middle or lower regions on days 26 through 28 A serious condition occurring in about 1 out of 2,000 live births, in which the spinal cord protrudes through the vertebrae Children with this condition have various motor, bladder, and cognitive difficulties

Maternal diet: Dutch Hunger Winter

Famine during WWII Adults who had been exposed to the famine as embryos and fetuses during the first trimester had increased rates of obesity, coronary heart disease, and glucose intolerance due to diminished insulin secretion compared with individuals exposed during the second or third trimester

Paternal health: diet

Males who overate in the years just before puberty tended to have sons and grandsons with a higher risk of diabetes, cardiovascular disease, and early death These are most likely due to alterations of epigenetic chemicals that regulate the expression of genes on the Y chromosome.

Embryonic period: neural plate

The neural plate is the origin of the entire nervous system. It follows a series of steps 1. Formation of a neural plate in the middle of the topmost layer of cells in the embryo 2. Lengthening of the plate into a neural groove 3. Folding of the neural groove inward 4. Closing of the two folds to form the neural tube. The top end of the neural tube will eventually expand to become the brain - end of the tube typically closes on day 25 after fertilization

Monitoring the health of the fetus

The simplest and most commonly used are measurements of the weight gain of the mother

Paternal and maternal impacts

A possible reason that mutations occur more often in sperm cells than in egg cells is that eggs are produced only once, whereas sperm cells must be regenerated about twice a month The more times DNA is copied during the process of forming sperm cells, the greater the chance for new mutations to occur

Fertility: infertility

About 11 percent of women ages 15 to 44 years and one out of six couples seeking to have a baby find out that they are infertile Most common: low sperm count in the father and damage to the mother's reproductive system through genetic conditions or disease Fertility begins to decline after about age 35 in both males and females - In some cases the causes of infertility are unknown

Birthing practices: breathing practices - Bradley method

Aims to reduce or eliminate the use of medications to relieve pain during childbirth and uses the partner as a coach

Fertility: in vitro fertilization (IVF)

Fertilization "in glass," meaning in a petri dish. Health of embryos can be evaluated and healthy embryos transferred to the mother's womb

Maternal diet: undereating

Prenatal malnutrition and adult risk for a number of disorders - obesity, type 2 diabetes, insulin resistance, and hypertension

Blastocyst

A ball of cells with a hollow core

Monitoring the health of the fetus: triple screen test

A blood test given to the mother than can identify abnormal levels of three compounds originating in the fetus or placenta that are indicators of possible fetal abnormalities Given to the mother between the 15th and 20th weeks of the pregnancy Three specific substances are measured: 1. Alpha-fetoprotein (AFP): a protein produced by the fetus 2. Human chorionic gonadotropin (hCG): a hormone produced within the placenta 3. Estriol: an estrogen produced by both the fetus and the placenta

Assessment of newborns: breast feeding - colostrum

A gooey substance that helps the newborn's digestive system

C-Sections

A procedure in which an incision is made in the mother's abdomen and uterus and the baby is removed by doctors. Highly effective in situations where the baby is in distress, the placenta blocks the birth canal, or the baby is in breech position Huge rise in c-sections - The increase in C-sections over time may be due in part to the increasing numbers of women over 35, in whom complications are more common - Part of the increase may be that doctors err on the side of caution to reduce the chances of possible harm to the mother or baby.

Birthing practices: breathing practices - impact on children

Prepared childbirth does not produce healthier mothers and babies than standard medical practice in the United States Prepared childbirth techniques are associated with shorter labor, more enjoyment of the birth, and less use of pain medication

Prenatal influence: teratogen

An environmental agent that disrupts the normal process of prenatal development 7 percent to 10 percent of birth defects are thought to be primarily caused by environmental factors - Incidence of serious birth defects is quite low (less than 2 percent) for women who follow recommended practices during the prenatal period Four general principles of teratogenic influences: 1. Dose 2. Genes 3. Cumulative effects 4. Timing of exposure One important exception is the brain, which is sensitive throughout prenatal development. Germinal period: teratogens most likely result in the death of the organism. Embryonic and fetal periods: the sensitive periods are different for each organ - Embryonic period, teratogens can affect the development of major organs and body parts, causing permanent structural damage. - Fetal period: tends to involve fewer major structural abnormalities and physiological defects such as a disturbance of heart, lung, or brain functioning.

Birthing practices: breathing practices - Lamaze method

Approaches childbirth as a natural process and uses a variety of techniques to reduce the perception of pain

Prenatal care guidelines: regular checkups

At least one visit prior to becoming pregnant and approximately 8 visits during the pregnancy are optimal. Physician's assistants, and obstetricians can monitor the mother's vital signs and weight gain. Some medical conditions occur during the pregnancy that can pose a grave risk to the fetus Many women in the United States who are in most need of prenatal care do not have ready access to this care

Stages of childbirth: three stages - stage 2

Birth of the baby Uterine contractions and the efforts of the mother --> push the baby, head first, through the birth canal - The baby's head is soft because the bones of the skull have not fused yet. After the head - the shoulders and the rest of the body slip through quickly. - 20 to 50 minutes Once the baby is breathing, the umbilical cord is cut, and the short remaining stalk is sterilized - it will fall off within a week or so to reveal the belly button.

Fetal period: physical growth

By 3 months: the fetus weighs about three ounces and is about three inches long. The major features of the face (forehead, cheeks, chin, eyelids, and nose) are present. The arms and legs have grown, and now the fetus can move them voluntarily By 4 months:, the fetus doubles in length and weight, and the size and strength of the legs are such that the mother can feel kicking movements End of the 5 months: the fetus doubles again in length to about 12 inches and weighs about a pound - Finishing touches: toenails, fingernails, and eyelids that can open and close - Covered with lanugo - Covered with vernix - Parents can see facial features and body parts of the fetus in an ultrasound image. By 7 months: the fetus is about 16 inches long and weighs about three pounds. At this point, all organs are functioning, though not at full capacity yet. The lungs are the last organ system to develop Last two months: fetus adds a few inches in length but gains four pounds in weight - Fat tissues essential for temperature regulation outside the womb develop. The mother's body passes antibodies to the fetus Most fetuses turn upside down

Glial cells

Cells in the brain that provide neurons with nutrients and remove waste, help guide them during migration, and insulate them with myelin Glial cells provide support and nourishment to neurons and remove waste products Growing rapidly and are fundamental to brain development.

Maternal diet: developmental programming

Changes to the physiology of the fetus from environmental stimuli during sensitive periods of prenatal development that result in long-term changes in health A lack of calories during the embryonic and early fetal period induces a set of metabolic changes that prepare the organism to make more efficient use of food in an environment where food is scarce Developmental programming is an adaptive mechanism in times of scarcity, but when food is abundant, a more efficient metabolism makes the individual prone to long-term obesity, which can lead to a cascade of other risks to health

Birthing practices: trends

Childbirth has moved from what was primarily a medical procedure in the 1960s to a more natural experience Increasing use of midwives and doulas Doula: a woman who has experienced childbirth before, present in place of or in addition to the partner.

Prenatal care guidelines: vitamins

Folic acid, iron, and calcium are the most commonly missing components of the diet of pregnant mothers, and they can be obtained by taking a prenatal multivitamin supplement.

Sexual differentiation: congenital adrenal hyperplasia

Genetic females can develop more masculine external genitalia if they have a rare genetic condition in which the absence of a particular enzyme in the adrenal glands leads to a cascade of reactions in the body that exposes the fetus to excessive testosterone

Sexual differentiation: complete androgen insensitivity

Genetic males can develop female external genitalia if they have a rare genetic condition in which they are insensitive to the action of testosterone

Maternal diseases: rubella

German measles, a virus that can cause multiple prenatal deficits when the mother contracts it during the first trimester - Mild effects in older children and adults but which can be disastrous for a developing fetus First trimester: 50 percent chance of having a baby with birth defects and intellectual impairment, indicating that rubella could disrupt any of the major organ systems Fetal period: fewer and less severe birth defects, although hearing loss and low birth weight could still occur

Prenatal influence: alcohol - fetal alcohol spectrum disorder (FASD) impact

Heavy doses of alcohol given to pregnant mothers disrupt several aspects of early brain development and lead to loss of neurons later in the pregnancy Reduced brain size, impairments to many brain regions and to white matter, and abnormalities in brain functioning

Monitoring the health of the fetus: triple screen test - alpha-fetoprotein

High AFP: may indicate that the baby has a neural tube defect such as spina bifida or anencephaly Low AFP, abnormal levels of hCG and estriol: associated with chromosome abnormality such as Down syndrome.

Fertility: helping infertility in females

If a woman has difficulty getting pregnant or there are frequent miscarriages early in the pregnancy, a procedure called in vitro fertilization (IVF) Fertilization occurs outside of the body altogether 1. The mother takes fertility drugs to stimulate her ovaries 2. Eggs are removed from her ovaries, fertilized in a petri dish with the father's or donor's sperm 3. It develops into embryos 4. Transferred back into the mother's uterus

Embryonic period

Implantation to week 8 All the major organs and body parts are established in rudimentary form 1. After implantation, the mass inside the blastocyst differentiates into multiple cell lines that differentiate further during the embyronic period, becoming internal organs, skin, muscles and bone, sense organs, and nervous system. 2. The embryo undergoes two major changes in the first two weeks of this period: 1) the formation of the neural tube and 2) development of the primitive cardiovascular system. 3. The placenta and other support structures develop in parallel to service the embryo's growing needs for nutrition and waste disposal. 4. Month 2: growth is very rapid. Tiny buds form on the upper torso that will become arms, hands, and fingers and on the lower torso that will become legs, feet, and toes. The heart develops separate chambers, and the liver and spleen begin to produce red blood cells. The stomach and intestines grow but are not ready to function yet. The face begins to form as two sets of structures that fuse in the middle toward the end of the second month 5. By week 8: the embryo is about 1 inch long and weighs about 1/30 of an ounce

Monitoring the health of the fetus: testing

In cases where the screening test is positive, there are genetic risk factors, or the mother is over 35 years of age, further tests can diagnose more than 100 conditions - Single-gene disorders, congenital defects such as muscular dystrophy, and Down syndrome

Monitoring the health of the fetus: ultrasonography

It is a painless procedure in which a technician uses a probe to beam high-frequency sound waves at the mother's abdomen. The reflections of the waves are used to construct a detailed two-dimensional image of the fetus, called a sonogram Used to measure the size and gestational age of the fetus, determine whether growth is in the normal range, and detect multiple fetuses Used to detect many developmental defects, such as abnormalities of the limbs, brain, and heart

Prenatal influence: drug abuse - understanding the impact

It is difficult to establish cause and effect in drug use. One problem is that mothers with a substance use disorder are likely to use or abuse multiple substances, including alcohol. Effects of alcohol can be quite similar to the hypothesized effects of cocaine or marijuana, raising issues of cause and effect Women with substance-use disorders are more likely also to have mood and anxiety disorders, and it is possible that some of the negative effects on child development occur because of a poor postnatal environment

Epigenome

Like a sleeve that fits over the DNA strand. Epigenetic chemicals (such as methyl groups and acetyl groups, which attach to the DNA) control whether particular genes are turned on or off at various points in development

Birthing practices: breathing practices

Many parents go through prepared childbirth classes The classes provide knowledge about the labor process, techniques for limiting the amount of pain the mother perceives (such as breathing exercises that distract the mother's mind from the contractions), and training for the father/partner or another person as a labor coach

Prenatal influence: alcohol - fetal alcohol spectrum disorder (FASD) parental influence

Maternal: cause epigenetic changes to basic structures such as the face and brain between conception and the middle of the embryonic period, when cells are differentiating - The more alcohol the mothers reported consuming at mid-pregnancy, the more likely their children were to have problems in behavior, attention, memory, and school performance from infancy through the age of 14 Fathers: may pass similar defects on to their offspring by way of alterations to the epigenetic material in their sperm cells

Thalidomide

Mild sedative that was prescribed for morning sickness Tests on mice revealed no harmful effects Thalidomide had these devastating and unanticipated effects only if mothers took it between 20 and 36 days after fertilization

Prenatal care guidelines: exercise

Moderate exercise for 30 minutes or more per day prior to becoming pregnant and during pregnancy is recommended. Exercise has many benefits, such as reducing stress, helping maintain appropriate weight, and strengthening muscles that contribute to back pain. Exercise of moderate intensity that does not jostle the uterus (such as walking, swimming, cycling, gym exercises, yoga) is recommended in mid- to late pregnancy.

Identical twins (monozygotic)

Most often occur at the end of the first week, when the mass of cells inside the blastocyst divides into two sets The two sets of cells have identical DNA, and each develops its own amniotic sac, although they share a single chorion and placenta. Less commonly: monozygotic twins result when the zygote splits in two during the 2-8 cell phase, resulting in two embryos, two amnions, two chorions, and two placentas.

Embryonic period: risk factors/issues

Most vulnerable period of development - When major body organs originate - Mothers generally are not aware they are pregnant 20-30% of embryos fail to complete development and are ejected from the uterus - Most miscarriages appear to involve a grossly malformed embryo, and about half have chromosomal abnormalities

Maternal diseases

Mothers can pass diseases or the effects of diseases to their babies in two ways: 1) through the placenta, 2) during the birth process The placenta stops bacterial diseases from crossing to the fetus but not viruses

Prenatal care guidelines: diet and weight gain

Mothers need 100 to 300 more calories per day during pregnancy. Gaining from 25 to 35 pounds is considered ideal, and the exact number depends on a variety of factors, including the mother's prepregnancy weight and height.

Twins: risks

Multiple births of both types of twins involve greater risk of damage to or loss of a fetus and a greater chance of babies being born with low birth weight Health risks to mothers are higher with multiple births, including a greater risk of high blood pressure and high blood sugar

Paternal health: de novo mutations

Mutations that are present in the child but not the parent. They occur during the process of gamete formation or fertilization and hence are unexpected based on the DNA of the parents.

Prenatal influence: smoking

Nicotine constricts blood vessels throughout the body, including those in the uterus, and this reduces the ability of the placenta to supply oxygen and nutrients to the fetus Cigarette smoke raises the level of carbon monoxide in the fetal bloodstream, and this displaces oxygen from red blood cells Smoking may have these effects in part because of modifications to the embryo's epigenetic profile

Fetal period

Ninth week after fertilization to about week 38 Overall weight of the fetus increases from 1 gram to about 3,400 grams (7 ½ pounds) and the length from 1 inch to about 20 inches

Nurse-Family Partnership

Nurses visit the home of low-income and teenage mothers several times during the pregnancy and once a month for the first 2 years of the child's life. They work to improve the mother's health, parenting skills, social support from the family, and the mother's educational and career prospects Fewer premature births, fewer subsequent pregnancies, better work and relationship circumstances, and lower rates of child maltreatment. Their children had greater school success and social development through third grade Cost effective: every 1 spent, 5 saved in costs to hospitals and schools

Paternal health: age

Older fathers are more likely to have offspring with schizophrenia, autism, and reduced IQ or social functioning The number of de novo mutations in the child went up with the age of the father but not the mother

Epidural

Pain medications are injected along the mother's spine to block sensation from the waist down There is no evidence that these medications have a negative impact on the newborn

Stages of childbirth: three stages - stage 3

Placental separation Contractions of the uterus push the placenta, other fetal membranes, and the remainder of the umbilical cord out 15 minutes

Assessment of newborns: Apgar Scale

Rates five of the baby's vital signs: Appearance, Pulse, Grimace, Activity, and Respiration - Rates at about one minute and again at five minutes after birth Babies receive a score of 0 to 2 on the five scales If the five-minute Apgar is 7 or higher, this is considered healthy If it is lower than 7, a neonatologist will be called to the delivery room to further assess and possibly intervene with the baby Scores below 4 require emergency medical attention Normal healthy newborns typically obtain scores of 8 to 9

Prenatal influence: teratogen - genes

Response to teratogens depends in part on the fetus's genetic vulnerability to a particular agent.

Sexual differentiation

Sexual differentiation provides a good example of bidirectional interactions between genes and sex hormones produced by the fetus's genital region 6 weeks: genetically male (XY) and genetically female (XX) embryos have two identical sets of internal genital structures. 7 weeks: in genetically male fetuses the SRY gene on the Y chromosome "turns on" and instructs one set of structures to form into the testes. The testes begin producing the hormone testosterone, which causes the female internal structures to wither away and male structures such as the prostate gland to continue to develop - In genetic females, the lower level of testosterone leads to degeneration of the male structures, and the female internal organs develop instead

Neuronal migration

Six weeks and continuing to six months The migration of neurons from the place where they are formed to their final locations in the brain Neurons move from the center of the neural tube outward to form the brain, either sliding up long fibers extended from the glial cells or moving laterally on their own. Migration is complete by the seventh prenatal month.

Embryonic period: neural plate defect - microcephaly

Slowed growth of the upper parts of the brain. The cortex forms, but it is much smaller than normal Microcephalic babies often survive with gross intellectual and motor deficits, and other problems associated with Zika virus effects

Maternal diseases: HIV

Some young mothers in the United States with the disease are unaware they have HIV and may thus pass the virus to their baby around the time of delivery or through breastfeeding 25 percent of infected children develop AIDS symptoms The majority of these children die by the age of 3

Fertility: helping infertility in males

Sperm can be collected from the father and injected into the mother's fallopian tubes, a process known as intrauterine insemination Typically, the mother takes fertility drugs to enhance ova production, and sperm is injected into her uterus

Prenatal influence: teratogen - dose

Teratogens generally have more negative effects if they are present in higher concentrations or over a longer period of time

Neurons

The basic information processing cells of the brain, begin to be produced in the fifth week of the embryonic period

Maternal diet: overcoming prenatal malnutrition

The effects of prenatal malnutrition can be overcome by effective intervention programs

Prenatal influence: teratogen - cumulative effects

The effects of teratogens appear to be greater when they are present in combination or when combined with stress, poverty, or poor medical care for the mother

Embryonic period: neural plate defect - anencephaly

The embryo will not develop a brain above the level of the brainstem, which leads to a fatal condition Die within the first year

Monitoring the health of the fetus: testing - chorionic villus sampling

The fetus's DNA can also be obtained by CVS. CVS can be carried out vaginally or through the abdomen, as shown here. Recent research reveals that CVS is about as safe as amniocentesis and provides results several weeks earlier. Can be performed as early as seven weeks after fertilization

Assessment of newborns: when babies are born

The first and most important thing for newborns to do: breathe on their own. As oxygen enters their lungs and moves to their bloodstream, their blood changes from a blue to a pinkish color The birth attendants quickly clear any mucus that might have lodged in the baby's throat, and the umbilical cord is cut. Staff quickly examine and weigh the baby and, if the mother is awake, return the baby to the mother for warmth and a first breastfeeding

Neurogenesis

The formation of new neurons within the brain neurogenesis is complete by the fifth month of the prenatal period

Embryonic period: heart

The heart begins to beat by about day 21 to 22 and blood begins to flow, making this the first organ system to begin functioning Heart is needed because the fast-growing embryo is in great need of nutrition and oxygen - These are supplied to an increasing extent by the placenta, via the umbilical cord, as the embryo grows.

Implantation

The process by which the blastocyst becomes attached to the uterus One of the most vulnerable processes in development Only about 30 percent of zygotes successfully implant

Fertility: surrogate

The surrogate can receive an embryo from the couple through in vitro fertilization or be artificially inseminated with the father's or a donor's sperm

Prenatal influence: teratogen - timing of exposure

The timing of exposure can be crucial

Neural differentiation

The transformation of neural stem cells into new types of neurons Neural differentiation occurs in parallel to migration. There are several different types of neurons that have different functions in the mature brain. Neurons have a genetically programmed destination in the brain. - After new neurons have migrated to their final destination, signals from neighboring neurons cause them to take on the shape and function of the other neurons, and they cannot be altered after that point. - These neurons can continue to function in old age

Prenatal influence: alcohol - fetal alcohol spectrum disorder (FASD)

There is no threshold level below which we can confidently say that alcohol has no effect Consists of three subgroups 1. Children with classic fetal alcohol syndrome (FAS) have facial deformities and mental disabilities - Their mothers drank the equivalent of five or more drinks at a time twice a week during the first trimester of pregnancy 2. Only some of the facial and cognitive symptoms 3. Has cognitive impairments but no physical defects The less severe subgroups were exposed to less alcohol overall and later in the pregnancy - Timing of exposure and dose are applicable

Fertility: in vitro fertilization (IVF) concerns

There was originally some concern that babies conceived through IVF might have developmental problems. Studies of children who were conceived by in vitro fertilization reveal that their development and psychological adjustment are normal throughout childhood and adolescence

Synapses

Tiny gaps across which an electrochemical signal can pass between two neurons Neurons that fail to make useful connections with other neurons degenerate quickly

Fraternal twins (dizygotic)

Two ova mature at the same time, are fertilized by two different sperm cells, and go on to have two amnions, chorions, and placentas, but the chorions and placentas may fuse together No more genetically speaking than any ordinary siblings Dizygotic twins are more common in some families and in some racial groups

Maternal diet: intervention programs

UNICEF: working in many countries around the world where people experience periodic, severe food shortages Women, Infants, and Children (WIC): U.S. government's supplemental food program. - Benefits: 1) reduced rates of prematurity and low birth weight, 2) fewer infant deaths, 3) and improved cognitive development

Maternal diet

Under- and overeating during pregnancy have been found to have long-term implications for the health of children and adults

Monitoring the health of the fetus: testing - amniocentesis

Using an ultrasound image as a guide, the physician inserts a thin needle through the woman's abdomen and obtains amniotic fluid, which contains skin cells sloughed off from the fetus. DNA tests are conducted on the fetus's skin cells. Typically conducted between the 15th and 18th weeks of the pregnancy and has only a slight risk of injury to mother or fetus or of early termination of the pregnancy (less than 0.5 percent)

Stages of childbirth: three stages - stage 1

Uterus pulls on the tight ring of the cervix (dilation) which expands it from less than 0.1-centimeter diameter to about 10 The contractions of the uterus in stage 1 help to push the baby's head downward so that it presses against the cervix Averages 12 hours with a first childbirth, 7 hours in subsequent births. There is a lot of individual variability

Premature babies: Als studies of Elizabeth in The Baby's Brain

Very premature and low-birth-weight babies can have normal brain, cognitive, moral and social development if they are given good medical care and raised in an environment with an optimal amount of stimulation Babies born one month-two months early often need very little special treatment, and will catch up to their full-term peers in developmental norms within a year or two

Maternal diet: overnutrition

When mothers are overweight or gain too much weight during pregnancy, they are at risk of having a high-birth-weight baby. Babies who weighed more than 8.8 pounds at birth were likely to be overweight at 6 to 13 years of age Infants born to mothers who had been obese during pregnancy tended to gain weight rapidly in early infancy and often became overweight in childhood and adulthood Having too much food during the pregnancy may disrupt the brain's system for regulating energy balance - The result is that infants simply eat too much, and this pattern becomes increasingly engrained during childhood and adolescence

Fetal period: vernix

White, cheesy substance. Protects the fetal skin from damage due to the fetus's movements or from soaking in the amniotic fluid

Prenatal care guidelines: medications

Women should not stop taking any medications they need and should consult with their physician before starting any new medications. The safety of most medications for the embryo and fetus is continually under investigation, and certain medications are known to be teratogenic (such as certain antibiotics and anticonvulsants).

Maternal diseases: HIV prevention

Women who test positive for HIV can take antiretroviral medication during their pregnancy, which reduces the risk of transmitting HIV from an infected mother to the baby to less than 2 percent HIV in mothers in developing countries is much higher - supplies of antiretrovirals are still inadequate

Premature babies

Youngest are about 22 weeks of age - Survival chances increase with each additional week the fetus can remain in the womb Correlational data reveal that teenage, African American, and Hispanic mothers are more likely to have low birth weight or preterm babies