Conception, Pregnancy & Birth
Creating a New Life
I. After ejaculation, sperm move through cervical mucus into uterus & reach fallopian tube within
~5 minutes; helped by propelling movements of uterus & fallopian tube
A. Prostaglandin, hormone found in semen, may intensify uterine contractions (not felt by woman) & shorten sperm travel time
B. Usually the sperm meet the egg in one of fallopian tubes
1. For fertilization, at least 1 sperm must penetrate transparent outer layer of egg
2. Sperm secretes enzyme hyaluronidase that dissolves this outer layer, allowing sperm to enter & fertilize
II. Implantation
A. Once egg is fertilized, conceptus is known as zygote; the one cell of zygote begins to divide as it travels down fallopian tube on its way to implantation in uterus
1. By a week after conception, zygote is hollow ball of 100 cells called blastocyst
2. 2 layers of cells now begin to form:
3. After implantation, trophoblasts & other cells proliferate & eventually form placenta, umbilical cord & amniotic sac
B. Immediately after implantation, embryo begins receiving nourishment from endometrial tissue of mother
C. Placenta is disk-shaped organ that attaches to uterine wall & connects to fetus by umbilical cord
1. Together, placenta & umbilical cord (attached to baby at navel & to mother at placenta) form lifeline between mother & fetus
D. Fetus's blood flows through 2 umbilical arteries in placenta & back to fetus from placenta by one vein

III. As embryo develops, placenta secretes the hormone human chorionic gonadotropin (HCG)
A. HCG is detectable through blood tests 8 days after fertilization, just as blastocyst is implanting & its presence confirms pregnancy
B. By ~11 th week of pregnancy, placenta itself secretes enough progesterone & estrogen to maintain the pregnancy & the corpus luteum dies
Pregnancy
I. After conception, woman is in state of pregnancy; lasts for time it takes fetus to develop
A. The period can vary, but time span from last menstrual period to birth of baby is usually 9 calendar months (10 lunar months, 40 weeks or 280 days)
B. At point at which fetus has optimal chance for survival outside uterus, pregnancy has reached term
II. Ectopic pregnancy – characterized by implantation of blastocyst in site other than uterus
A. Rate of ectopic pregnancy has increased 5-fold since 1970 & is now main cause of maternal morbidity (illness) & mortality in first trimester
B. Women 30 years of age & older and African-American women are at greater risk for ectopic pregnancy
C. Major risk factors believed to predispose one to ectopic pregnancy
D. Essential that ectopic pregnancy be diagnosed quickly; CDC says all women should be aware of its signs & symptoms; if experience symptoms, seek medical help right away
E. Such symptoms indicate possibility of ectopic pregnancy – ultrasound can confirm ectopic pregnancy by 6 weeks gestation, facilitates less destructive & costly treatment

III. Confirming pregnancy – many signs & symptoms caused by other things (emotional, endocrine, systemic conditions); caution advised
A. 3 sign categories: presumptive, probable, positive
1. Presumptive signs – not all pregnant women experience all these symptoms; may indicate pregnancy but may occur when woman is not pregnant
2. Probable signs – presumptive symptoms plus:
3. Positive signs – not present until the 17 th which can confirm pregnancy
week after conception; 3 of them, any one of
B. Women today do not need to wait months to confirm a pregnancy; for health of woman & developing fetus, it is best not to do so
1. Echography or ultrasonography (measures sound waves as they pass through tissues of various densities, each returning its own echo) can be done as early as 4 weeks
C. Pregnancy tests – pregnancy confirmed by presence of HCG, which is present in blood & urine of if pregnancy exists
1. Most frequently used lab test is beta subunit HCG radioimmunoassay, which measures
HCG in blood sample; can confirm pregnancy about 8 days postconception
D. Home pregnancy tests – test for presence of HCG in urine & can be used as early as day menstruation should have begun

Fetal Development
I. Prenatal development has 2 stages (embryonic & fetal); 9 month pregnancy is commonly viewed as consisting of three 3-month developmental periods (trimesters)
A. Embryonic stage (from Greek word embryo, to swell), which lasts 2 months
B. Fetal stage (from Latin fetus, the young one) from start of 3 rd month when it begins to look human to birth
II. First trimester (weeks 1 – 12) – most of embryo's physiological systems & body parts begin to form
A. At end of 1 st month, embryo is ~0.25" (0.6 cm) long & 3 cell layers have formed
1. Ectoderm (outer layer) –
2. Mesoderm (middle layer) –
3. Endoderm (inner layer) –
B. At end of 2 nd month – embryo is ~1.25" (3 cm) long & weighs 1/30 ounce (0.9 g); head represents almost half of embryo's total bulk
C. When 3 rd month begins – developing child is called fetus; fetus, afloat in amniotic fluid, is
3" (7.6 cm) long & 1 ounce (2.8 g) in weight
1. It can move, but its motions are not yet felt by mother
III. Second trimester
A. During fourth month (first month of 2 nd trimester), greatest amount of fetal growth occurs; fetus is now 6" (15 cm) long; lower body is growing increasingly larger
B. During 5 th cm) long; it sleeps, wakes & has a preferred body position
C. During 6 th
month, halfway point of pregnancy, fetus weighs ~1 lb (454 g) & is ~12" (30
month, fetus grows ~2" (5 cm) & gains another pound
1. Fetus's eyes are formed, it is sensitive to light & it can hear uterine sounds
IV. Third trimester – baby positions itself more or less for birth; most common fetal position or presentation is head down
A. As fat layer is laid underneath skin, fetus takes on a more babylike form

B. By end of 7 th month, generally agreed, the baby can live outside the uterus, although babies have survived when born much earlier & cared for in neonatal intensive care units
C. By end of 8 th month, fetus weighs ~5 lb, 4 oz (2384 g) & ~20" (51 cm) long
Bearing a Healthy Infant: Prenatal Choices
I. Birth attendant options – woman's health affects pregnancy experience & developing child's health; choice of person to advise during pregnancy & aid during labor/delivery is important
A. In US, all doctors are trained in med school in pregnancy/birth procedures, but generally a family-practice specialist (general practitioner) &obstetrician deal with pregnancy
1. Obstetrician has specialized advanced training in this area; many women specialize in this area; many women seek out women obstetricians
B. Midwifery – historically, American midwives were laypeople who helped with birth deliveries; today nurse midwives are registered nurses (RNs) who get advanced training
1. Many states make nurse midwives pass national certification exam to get licensed
2. Nurse midwifery is good choice for families who consider birthing to be natural process not requiring highly technological interventions
II. Birthing alternatives – usually 3 major settings in US where labor/delivery typically occur; often attendant choice tied to setting where attendant chooses to or is allowed to practice
A. Hospital birth – not long ago, most babies born in hospital delivery room with mother heavily drugged & father barred from proceedings
1. Biggest change is increased participation of fathers in birth of children – they are now simply present or participate more by holding baby as it emerges or cutting cord
2. Most hospital facilities consist of separate rooms for labor, delivery, recovery
3. Some hospitals provide more home-like birth setting, a birthing room attached to labor & delivery suite often run by nurses & midwives

B. Home birth – with nurse midwife; this option is growing; option for only healthiest women; midwives trained to screen out women at risk of complications in labor/delivery
C. Freestanding birth centers – compromise between traditional hospital delivery (medical intervention) & home birth; homelike birth experience outside hospital setting
1. Most are licensed by state & often run by nurse midwives; typically limit clientele to lowrisk pregnancies
2. Women monitored through pregnancy by nurse midwives & referred to hospital for delivery if complications arise prenatally
III. Prenatal care – typically consists of monitoring fetal development, screening for high-risk pregnancy & educating those involved about pregnancy & childbirth
A. For most normal pregnancies, 10 –12 prenatal care visits starting by 6 th – 10 th week of pregnancy are optimal; high-risk pregnancy – more visits may be needed
B. Prenatal evaluation starts with personal health history, relevant social & emotional factors, employment of parents, work environment conditions & relationship stability
1. Practitioner wants to know support system for mom & child; many factors (medical & non-medical) can affect their well-being
2. Do lab test series:
3. Do examination of cervix & take family history
IV. Nutrition & weight gain – maternal nutrition directly affects fetal growth & development; fetus depends on mother for nutrition & can deplete her supply of necessary nutrients
A. Mother needs iron supplements to prevent anemia; iron is major component of hemoglobin
1. Protein
2. Trace minerals (zinc, cobalt)
3. Vitamins
B. 1990 – Natl. Acad. of Sci. says that food, not supplements, is preferred source of recommended daily allowance (RDAs) of nutrients needed for healthy pregnancy
1. Major exception to recommendation is iron supplementation; adequate amounts of iron cannot be consumed through food sources

2. Report recommends that all pregnant women have their diet assessed for nutrient content; prenatal nutrient counseling also essential
C. In past, pregnant women were placed on strict regimens to prevent them from gaining >~20 lb; obese patients were put weight-reduction programs
D. Current recommendations for healthy weight gain during pregnancy vary with prepregnancy wt
V. Exercise during pregnancy – safety of aerobic exercise during pregnancy has been questioned relative to its effect on developing fetus
A. Aspects of fetal development some think may be affected by aerobic exercise: potential fetal distress, intrauterine growth retardation, fetal malformations & prematurity
B. To ensure safety of both mother & baby, pregnant women should follow exercise guidelines of Amer. College of Obstetrics & Gynecology (ACOG)
C. It is recommended that pregnant women exercise regularly (3 – 5 times/week) & avoid outdoor exercise on hot, humid days
1. Regular fluid intake during exercise & consumption of adequate calories daily (additional
200 – 300 calories) are essential for safe exercise program
D. If woman experiences fatigue, shortness of breath, dizziness, nausea, uterine contractions, pain, vaginal bleeding or decreased fetal movement during exercise —> stop immediately
Threats to Having Healthy Infant: Background Information
I. Many risks to healthy pregnancy in modern technological society – chemical/radiation exposure at work site/home, lifestyle factors (smoking, drug use/abuse, infectious agents

II. 1998 – Natl. Center for Health Statistics reported infant death rate of 7.3 deaths per 1000 births in US; significant decrease from 1988 (10.1 per 1000)
A. Compared to other developed countries, US ranks 25 th in infant deaths
B. Infant death rate is twice as high for African-Americans as for whites
III. Teratology – search for causes of birth defects
A. Teratologists estimate that 5–6% of birth defects caused by chromosomal defects, 8–10% by mutant genes, ~6 – 10%caused by environmental factors (toxic chemicals, drugs)
B. Birth defects are one of most important causes of infant death in US
IV. 2 nd leading cause of infant death is low birth weight (<5.5 lb) & very low birth weight (<3 lb, 4 oz); together they substantially raise infant's chance of dying in 1 st year
A. Especially true for African-Americans, for whom low birth weight is leading cause of infant death in US
B. Two types of low birth weight
C. Risk factors associated with low birth weight
D. Despite the fact that hormones account for & influence sexual differences, males & females produce the same ones (estrogens, progesterones – female; androgens – male)
Threats to Having Healthy Infant: Drugs & Other Substances
I. Any drug taken by pregnant woman can potentially pass through placenta to fetus; if drug affects mother, it will also affect developing fetus; an adult dose can be overdose for fetus
A. Liver of fetus cannot metabolize drugs as well as adult liver —> unchanged drug can affect fetus differently from mother
B. Drugs could also alter mother's metabolism, influence hormones in bloodstream & affect placental functioning
II. Over-the-counter drugs (OTCs) – many Americans are polydrug users; OTCs are sold legally without a prescription & widely used for self-medication purposes

III. Cigarette smoking – most toxic harmful exposure during pregnancy; definitely harmful to unborn baby
A. Smoking during pregnancy associated with:
B. Infants born to smoking mothers weigh an average of 7 oz. less than those born to nonsmoking mothers
1. Infants weighing <2500 g (5 lb., 8 oz.) classified as low birth weight infants & have greater mortality rates
2. Cause of low birth weight infants in these mothers thought to be O
2
deprivation (not proved)
3. Cyanide in smoke may cause vitamin depletion –
4. If smoking is stopped during first 4 months of pregnancy, birth weights approximate those of infants born to nonsmokers
IV. Marijuana – research currently under way; preliminary results – suggest many potential dangers involved in using it during pregnancy
A. Tetrahydrocannabinol (THC; primary psychoactive agent in marijuana & other cannabinoids) can pass through placental barrier & affect placental function
B. Animal studies identify marijuana is teratogen (agent capable of causing birth defects)
C. Ottawa Prenatal Prospective Study – collected data from >700 pregnant women in Ottawa region since 1978; preliminary findings show that:
1. Infants born to mothers who regularly smoked marijuana during pregnancy have marked decrease in response to light repeatedly directed at their eyes
V. Alcohol – estimated that 20% of pregnant women in US drink alcohol while pregnant; this is even higher among some groups of women: smokers (41%) & unmarried (35%)
A. Overall percentage using alcohol while pregnant is decreasing significantly but trend is not seen in women with a high school education or less or in younger women (18 – 24)
B. Sterling Claren (teratologist, Seattle Children's Hosp.) – alcohol may account for up to 20% of all mental retardation in US

C. Particular pattern of deformity with mental impairment occurring in offspring of these heavy drinkers is called fetal alcohol syndrome (FAS); traits of such infants are:
1. Unusual facial features like:
2. May also have heart defects
3. May also have dysfunctions of the central nervous system
4. May also have growth deficiency
5. Growth & mental deficiencies appear to persist into adulthood
D. No safe level of alcohol consumption during pregnancy established
VI. Cocaine
A. CDC study (2003) – cocaine use starts at a young age; 7.2% of 9 cocaine at least once in their lives th graders report having used
B. Cocaine use by pregnant women associated with higher rates of miscarriage, low birth weight, stillbirth, birth defects, premature labor & long-term mental defects in child
VII.
Heroin & other narcotics
– common narcotics ( opiates ): heroin, morphine, codeine, paregoric, hydromorphone HCl (Dilaudid), laudanum, meperidine, synthetic narcotic methadone
A. Except for heroin (outlawed), these drugs are used in medical practice for specific reasons under close supervision; with respect to these drugs, we refer to drug abuse
B. Use of & addiction to heroin & other opiates in pregnant woman results in narcotized fetus who must go through withdrawal
VIII. Steroids
– prescribed drugs: sex hormones & other specific chemicals ( cortisol, prednisone ) used to treat kidney inflammations & tissue damage due to rheumatic fever & other diseases
A. Can cross placenta & cause fetal diseases
IX. Diethystilbestrol (DES) – synthetic nonsteroid estrogen first prescribed in 1950s to prevent miscarriage
A. 1971 – discovered that DES caused a specific vaginal cancer in some female offspring of women who took the hormone during their pregnancy before the 18 th week of gestation

X. Birth control pills – studies of women who took oral contraceptives during pregnancy (before it was known) lead to belief that pill increases risk of heart & limb defects
Threats to Having Healthy Infant: Diseases
I. Certain diseases can be passed from mother to fetus, but significance varies with stage of pregnancy
II. German measles (rubella) – most harmful to the fetus in first trimester (effect is almost nil after 3 rd or 4 th month)
A. Common effects on infant include:
B. To prevent rubella & effects, it is recommended that women who have not had rubella be vaccinated well before they decide to conceive
III. Diabetes – insulin deficiency that affects sugar metabolism & that can influence fetal weight
& complicate delivery
A. Infants of diabetic women may have high birth weight (≥10 lbs) & a higher than average mortality rate
IV. Acquired Immune Deficiency Syndrome (AIDS) – viral disease characterized by depression of immune system & presence certain opportunistic infections & malignancies
A. Fetus can get infected when human immunodeficiency virus (HIV) crosses placenta of infected woman or during birth
B. Currently estimated that~26% of infants born to HIV-positive mothers will also be HIVpositive & may contract AIDS
V. Syphilis – an STI; a common cause of stillbirth & can infect fetus when spirochetes cross the placenta
VI. Gonorrhea – an STI that affects the eye as baby passes through vagina & can, by transmission through placenta, eventually cause a form of arthritis
VII. Herpes Genitalis – STI caused by herpes simplex virus (HSV)
A. If blisters present on genitals of mother at time of delivery, virus can be absorbed by baby, causing encephalitis, brain inflammation & possible death

VIII. Chlamydia – another STI; caused by intracellular parasite ( Chlamydia trachomatis )
IX.
Genital warts
–
STI caused by human papillomavirus (HPV); infected mothers may transmit
HPV to fetus in utero or during birth; found in children born to HPV-infected women
A. More common in infected infants is respiratory papillomatosis, which causes hoarseness & respiratory distress
Threats to Having Healthy Infant: Rh Incompatibility
I. Rh factor is substance in blood of ~85% of population – if it is present, person's blood type is Rh positive (Rh+); if it is not present, blood type is Rh negative (Rh-)
A. Problem exists in pregnancy when Rh- mother is pregnant with Rh+ child, who inherited positive factor from Rh+ father
B. Treatment – accomplished by transfusion of newborn infant with Rh- blood to stop RBC destruction
Threats to Having Healthy Infant: Testing for Disorders
I. Amniocentesis – drawing of fluid from amniotic sac for purpose of diagnosing fetal abnormalities; cannot be safely performed until 16 th week of pregnancy
A. Sonogram (ultrasound picture) taken to show fetus outline so needle used will not touch baby
B. Maternal age older than 35 carries higher risk of chromosomal disorders (Down's syndrome); amniocentesis recommended for these women
II. Chorionic villus sampling (CVS) – newer technique approved by FDA; ideally performed at 8 –
10 weeks into pregnancy
A. Chorion is outermost protective covering of growing embryo; villi are threadlike, vascular protrusions growing on chorion outer surface

III. Maternal serum alpha-fetoprotein (MSAFP) testing – used for detecting fetal abnormalities early in pregnancy
A. Blood test performed at 15 – 18 weeks of pregnancy; used to detect neural tube defects like spina bifida (open spine) & anencephaly (lack of higher brain structures)
B. Abnormal levels of MSAFP also indicate several other conditions
C. It is a screening test that detects potential problems, not a diagnostic that can confirm these conditions with certainty
Maternal Health Problems During Pregnancy
I. ~20% of all pregnant women & their babies are at risk, meaning that the mother and/or baby could suffer some adverse effects during pregnancy, labor or delivery
A. Influences on the risk status of a pregnancy
B. ~60% of maternal deaths in pregnancy & childbirth in US are due to hemorrhage, infection, preeclampsia, eclampsia & convulsions
II. Hypertension – blood pressure above normal when heart is contracted or relaxed or both
A. Women with history of hypertension or who becomehypertensive in pregnancy need attentive medical supervision, but condition does not preclude successful pregnancy
B. Preeclampsia – pregnancy induced hypertension accompanied by swelling of face, neck & upper extremities; they swell when their tissues retain too much fluid (edema)
1. Proteinuria -
2. Edema (tissues swelling) –
D. Eclampsia – refers to preeclampsia events, plus convulsions or coma, & can be fatal
III. Nausea & vomiting – exact cause of nausea & vomiting in early pregnancy is unknown but thought to be caused by hormonal changes; usually called morning sickness
A. Nausea often occurs early in the day & dissipates relatively quickly; as body adjusts to pregnancy, nausea & vomiting disappear; suggested approaches to treat it are:

B. Severe continuous vomiting in pregnancy (hyperemesis gravidarum) can be serious; can lead to following symptoms & threaten pregnancy:
C. Bed rest & sedation are frequently necessary; in extreme cases, hospitalization & intravenous feeding are required
IV. Hemorrhoids – varicose veins of anal area; caused by same pressures that create varicose veins in legs
A. Increased flow of blood to pelvic area during pregnancy results in added pressure of blood flow, which stresses inelastic veins
B. In effort to accommodate increased blood flow, veins are stressed, resulting in swelling, pain
& bleeding
V. Other conditions – associated with pregnancy & nonserious, but often irritating
A. Chloasma (mask of pregnancy) – a usually yellow to brown patch of skin pigmentation that appears on faces of white women
B. Stretch marks – more common in white women than in others; visible white streaks in skin of abdomen & breasts, which enlarge during pregnancy
C. Hair loss – sometimes occurs due to increase in hormone production; temporary when it does occur
D. Reddish, branchlike vascular spiders in neck, chest, face & arms that are due to high estrogen levels &vascular weakness
E. During last few months of pregnancy, weak & slow contractions of uterus occur (Braxton-
Hicks contractions)
Childbirth
I. Parturition – derived from Latin term meaning "to produce" it is the process of giving birth
A. Begins with labor (contractions of the uterus, a gradual opening of the cervix, & purposeful bearing down by the women)

B. Sometimes women experience false labor, a phenomenon common in late pregnancy, characterized by brief uterine contractions,
C. True labor is characterized by:
D. Usually cervix begins to soften & dilate a few days to a few weeks before actual delivery time
II. Labor
A. Takes place in 3 distinct stages from an obstetrician's point of view
1. Stage I – period from the onset of labor to the point at which the cervix is fully dilated
2. Stage II –period from full cervical dilation through birth of the child
3. Stage III – period from infant's birth to delivery of placenta or afterbirth
B. Labor usually begins with the first of the contractions that will mark the whole first stage
1. Often contractions are irregular at first & of unequal length
2. In true labor, they eventually occur in settled pattern like contractions of 30 – 40 sec occurring every 2 to 3 minutes
3. Usually amniotic sac (bag of waters) ruptures spontaneously near beginning of labor, experienced in either rush or trickle of fluid through vagina
C. Medical attendants monitor the fetal heartbeat regularly with stethoscope on mother's abdomen & perform vaginal examinations periodically
III. Delivery – considered good medical practice for doc or midwife to control delivery to prevent a too sudden or too forceful ejection of baby
A. Goal is to prevent injury to CNS of baby or injury to mother's perineum (area between vulva
& anus)
B. Usual delivery is divided into 3 phases: delivery of head, of shoulders & of the body and legs
C. Crowning is presentation of baby's head at vaginal opening or introitus; breech delivery- baby presents hip, body, shoulder & head in that order
1. Breech delivery is rare but can be hazardous to mother &/or baby for several reasons

2. Breech delivery can be hazardous to baby in that umbilical cord may separate or be compressed between baby & inner uterine wall, depriving baby of oxygen
D. When resistance inhibits normal delivery mechanism, forceps delivery may be necessary; such conditions include:
E. After delivery, umbilical cord is clamped & cut
IV. Delivery of placenta – usually occurs ~5 minutes after baby is born
A. When placenta emerges through uterine contractions, doc or midwife examines it carefully to be sure it is completely smooth
B. If contractions stop before placenta is expelled, manual techniques or injection are used to facilitate its delivery
V. Drugs used in childbirth
A. Anesthetics inhibit perception, not just of pain, of touch & all other sensations in mother
B. Local anesthetics & local & regional analgesics (reducers of pain perception) inhibit feelings
& sensations in specific parts of body
C. Local anesthetic injected around nerves in given spinal area reduces sensory feeling in specific body area
1. Local anesthetic is generally administered during later part of first stage of labor & during all of second stage
D. Different areas of pelvic region are anesthetized by different procedures
1. Saddle block or epidural block –
2. Paracervical block –
E. Potential risks of drugs – used successfully & safely during labor for many years so use is not alarming; there are risks but they are minimal

VI. Natural childbirth – drug-free childbirth or prepared childbirth; called this because it involves education & practice
A. Electing a natural delivery often means that parents are more involved in pregnancy than they would be with more traditional approach
B. Movement began early in 1930s with Dr. Grantly Dick Read, an English physician; he developed childbirth method with no anesthetics or analgesics & published his ideas
C. Velvoski (Russian, 1950) – published theory of psychprophylaxis, which was taken up in
France by Fernand Lamaze
1. Psychoprophylaxis is based on premise that with aid of supportive coach (usually husband, but any concerned, interested adult friend can do it)
2. A woman with positive attitudes can reduce stress & tension of parturition & relax pelvic muscles
D. Bradley method
– started in Denver area in 1960s by Dr. Robert Bradley, a gynecologist & obstetrician; it has gained popularity recently
E. Leboyer method – related to natural, drug-free childbirth but focus is on environment newborn enters rather than labor; has strict adherents but others draw features from it
F. Natural methods not suited to every pregnancy; mother's health & pain threshold influences whether to do it
VII. Cesarean section (C-section) – delivery of fetus & placenta through incision in walls of abdomen & uterus; performed when vaginal birth would be risk to mother or baby
A. Most common reasons for C-section
B. 2001 – C-sections accounted for 24.4% of all deliveries in US; all-time high & jump of 7% from 2000; some perceive increased rate as beneficial
1. They point to possibility of fetal & maternal death from childbirth & ruptured uteri
2. Other reasons for rise in C-sections are effects of labor/delivery on women's bodies

C. Opponents say rise in C-sections say it is result of OBs' concerns about malpractice lawsuits
1. May be why women who have previously had C-sections are not allowed by hospitals & doctors to have vaginal deliveries
D. Disadvantages of C-sections
VIII. Premature birth – when baby is born before normal gestation period is completed but still has chance of surviving estimated that ~12% of births in US are premature
A. Premature infant is usually born from 28 – 34 weeks gestation; some as young as 24 weeks; generally weigh <5.5 lb (2500 g)
B. Prematurity caused by many factors
C. Premature baby born before some of its body systems can perform adequately
1. Respiratory system in particular is immature in these babies – may forget to breathe & may have difficulty in moving air through respiratory tract
2. Sometimes their lung surfaces are unable to work with necessary amounts of oxygen needed for survival because of lung immaturity
3. Premature infants often have difficulty swallowing & digesting food, so they require special IV feedings
D. Neonatal intensive care – medical specialty of premature infant care
Breastfeeding
I. To prepare breasts for making milk, glandular tissue & ducts proliferate during pregnancy as result of placental secretion of estrogen, progesterone & lactogen
A. These developments account for increase in breast size in pregnancy – large amounts of estrogen & progesterone secreted by placenta prevent milk production before birth

B. 28 – 48 hours after delivery, lactation process begins
1. For first 3 or 4 days, a thin, yellowish liquid (colustrum) is secreted by breasts
2. Actual milk production begins between 4 th & 7 th days & by 7 th day, mature milk production begins
C. Infant's sucking stimulates nipple nerve cells, brain receives the message & stimulates pituitary to secrete oxytocin, which, in turn, stimulates ejection of milk from breasts
1. When milk is forced out, mother feels tingling sensation (letdown reflex) ~30 – 60 sec after suckling begins
2. Continued milk supply is dependent on sucking so infant's demand regulates breasts' supply; baby sucks longer —> more milk made, baby sucks less —> less milk made
II. Breastfeeding benefits baby by providing diet of balanced, uncontaminated nutrients & antibodies against disease; mother benefits, too (leads to its recommendation over formula)
A. Nursing helps uterus return to nonpregnant shape & postpones return of menstruation
(although it is not sufficient contraceptive by itself)
B. Breast cancer rates are lower for mothers who breastfeed
C. Breastfeeding encourages close attachment (bonding) of infant & mother
D. Breast milk is less expensive than formula milk
III. Support for breastfeeding mothers is provided by organizations like La Leche League & numerous books & articles
IV. Some women do not produce sufficient milk to breastfeed; others may not breastfeed because it is inconvenient or for other reasons; may be case with mothers who smoke cigarettes
Sexual Activity During Pregnancy and Delivery
I. Some, perhaps many, pregnant couples afraid to have intercourse for fear of hurting fetus
A. Frequency & kinds of sex that are safe during & after pregnancy determined by personal preference & health
B. Under certain physical conditions, coitus might add risk to pregnancy
II. Sexual feelings can change during pregnancy
A. Woman's desire may be influenced by:

III. Intercourse after delivery depends on many factors
IV. Most OBs prefer that couples delay intercourse until after first postdelivery examination, usually 4 – 6 weeks after delivery
Hormonal Influences on Prenatal Development: Becoming Male or Female
I. Normal sexual differentiation – in uterus, fertilized egg always develops as if it were going to be female
A. If Y chromosome is present, male develops; process of Y chromosome leading to testes is not fully understood
B. If no Y chromosome is present, ovaries develop instead
– process of gonadal development or sexual differentiation does not start until start of second month after conception
II. Gonadal development is significant because the gonads produce their own hormones, which, in turn, affect the development of other structures in reproductive system
A. Fetal testes produce testicular hormones (androgens) that instruct body to develop vas deferens & other male reproductive structures
1. Fetal testes also produce a defeminizing hormone (Mullerian-inhibiting hormone; MIH or
Mullerian-inhibiting substance; MIS)
B. Tissue from which reproductive organs develop is part of one of a pair of embryonic ducts:
Mullerian duct or Wolffian duct
1. Mullerian duct -
2. Wolffian duct –
C. Androgen presence/absence decides if certain tissue piece becomes:
D. Structures that develop from same tissue in this way are homologous structures
III. Differentiation of male & female brain is brain dimorphism – new area of study
A. Brain differentiation may extend into first few days or weeks after birth
B. It appears that brain differentiation is ambitypic (it allows for coexistence of both masculine
& feminine nuclei & pathways in some, if not all, parts of brain)

Abnormal Sexual Differentiation
I. Occasionally something goes wrong with sexual differentiation
A. Possible for genetic sex/genotype ( chromosomes ), gonadal sex/phenotype ( testes, ovaries ) & internal sex structures (uterus, fallopian tubes, prostate, vas deferens) to differ
B. Condition where X & Y chromosomes present but tissues insensitive to testosterone produced by fetal testes is called testicular feminizing syndrome; most common form of hermaphroditism,
1. Hermaphrodite can also be formed by secretion of excessive level of androgen from adrenal gland of female fetus; called adrenogenital syndrome
II. Differentiation between true hermaphrodites & pseudohermaphrodites –
A. True hermaphroditism is very rare & is characterized by presence of both ovarian &testicular tissue (called ovotestes)
B. Pseudohermaphrodites have gonads that match their chromosomes but their other reproductive structures may be mixed, much more common form of hermaphroditism
III. Sexual differentiation problems traced to chromosomes
A. Turner's syndrome – caused by the presence of only 1 X chromosome instead of 2
B. Klinefelter's syndrome – caused by an XXY genotype; they are boys that appear normal until puberty, but then do not develop normal secondary sexual characteristics
IV. Inguinal hernia – testes descend into scrotum through structure called the inguinal canal; this normally occurs by the 7 th month of fetal development
A. If inguinal canal does not close properly after testes descend or if it opens up afterward, it is possible for intestine to move down canal & enter scrotum
V. If testes do not descend down inguinal canal (~2% of male newborns) condition is called cryptorchidism (more commonly undescended testes
A. Usually testes will descend during early childhood or by puberty
B. If they do not either surgery or hormonal therapy is needed for 2 reasons
Infertility: Background
I. Infertility (the inability to reproduce) can cause great emotional anguish for people who want children; > 5 million people of childbearing age experience infertility
A. Resultant unhappiness, accompanied by tension, frustration & even resentment can damage the health & marriages of infertile couples

II. Types of infertility
A. Primary infertility –
B. Secondary infertility –
III. Women & men can both contribute to infertility – caused by woman's problem in 35% & by male's problem in 35% of cases & by both male & female in 20% of cases
Infertility: Causes
I. Among leading causes in women are untreated gonorrhea & Chlamydia infections
A. May cause tubal occlusion in women & chronic cervicitis, both of which produce subfertility
B. In men, these diseases can cause epididymitis if untreated, leading to blocked sperm ducts & poor semen quality
II. Other diseases that can lead to infertility
III. Several drugs can inhibit sperm production or sperm function, including antimalarial drugs, antihypertensives & Ca channel blockers
IV. Age is factor in infertility for women & men
A. Older a woman is, more likely she is to be infertile; women most fertile in mid-20s
V. Exposure to toxic substances may be cause of infertility when there is no discernible anatomical cause
VI. Lack of knowledge about anatomy, physiology & reproduction can lead to infertility in some couples
Infertility: Treatment
I. At least half of people who receive treatment ultimately conceive; 5% of infertile couples get pregnant without any treatment

II. Fertility may be enhanced with some simple techniques; the first 2 below may be enough
A. Having woman lie on her back for 1 hour after coitus to aid sperm in traveling up rather than out of vagina may help
B. More frequent intercourse, especially near ovulation time; identify ovulation time & have sex near that time
III. If simple methods aren't enough, first step is examination to determine why there is a problem; there are several basic infertility screening procedures
A. Semen analysis
B. Basal body temperature (BBT) recordings – woman records body temperature with oral or
BBT thermometer daily
C. Fuller evaluation of ovulatory function – biopsy (microscopic examination of excised tissue) of endometrium performed
D. Tubal patency tests – dye projected through fallopian tubes & observed by X-ray to detect any blockage; also called hysterosalpingogram
E. Postcoital examination
–
2
–
4 hours after sex, microscopically examine cervical mucus ; doc checks for several conditions of mucus that can be fatal to sperm
F. Hormone monitoring – ovulation prediction kits sold over counter; measure level of LH, hormone causing ovulation midway through menstrual cycle
G. Cervical mucus evaluation - evaluated for elasticity, its nature just before ovulation (should be thin, watery, salty, stretchy), presence of cells, debris & proper pH
H. Ultrasonography –
I. Hysteroscopy – uterus expanded with CO
2
gas or by liquid & observed through hysteroscope
(long. narrow, illuminated instrument inserted through cervix to uterus)
IV. Screening procedures determine infertility causes in ~85% of cases; remaining cases stay unknown —> once cause or causes known, treatments applied
A. Ovulation cessation restarted through hormone therapy or by increasing body fat through nutritional therapy
B. Blocked fallopian tubes cleared by microsurgical techniques
C. Artificial insemination (projecting sperm from male donor into female's vagina by mechanical means) used when male is not fertile

D. For women whose fallopian tubes are irreparably blocked, docs in special clinics unite partners' sperm & ovum outside woman's body; called in vitro fertilization
Infertility: Assisted Reproductive Technologies
I. In last part of 20 th century, advanced reproductive technologies have been developed to assist infertile couples in conceiving
II. In vitro fertilization (IVF) – incorrectly labeled test tube baby procedure
A. Remove ripened egg(s) from female's ovary, fertilize it with semen, incubate dividing cells in lab dish & then place developing embryo in uterus at right time
B. IVF success rate is not high – birth rate per egg retrieved was 22.3% in 1995
C. Women who get pregnant with >1 child via IVF or GIFT have 2-fold higher risk of developing preeclampsia than women who get pregnant spontaneously
D. IVF raises many ethical issues
III. Gamete Intrafallopian Transfer (GIFT) – ovum transferred to one or both fallopian tubes during laparoscopy with fertilization occurring in tubes as it does naturally
A. Embryo implants in regular conception cycle
B. It is an option only for women with open fallopian tubes
IV. Artificial insemination - ~20,000 babies yearly produced by artificial insemination; 2 types
A. Artificial insemination by a husband (AIH) – generally attempted when husband has one of a number of problems: misplaced urinary meatus, impotence, low sperm count
B. Artificial insemination by a donor (AID)
1. Done when there is no husband or
2. Donor is screened for health factors & matched to husband in physical appearance & genetic background though generally his identity is unknown to receivers
3. For legal reasons, if husband can produce even minimal amount of sperm, some docs miss his sperm with donor sperm before insemination
C. Artificial insemination allows people to experience natural parenthood even when unable to conceive through intercourse