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
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
1. One important function of placenta is to keep blood systems of mother & child
separated from each other
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 ~11th 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)
1. Most women deliver within 2 weeks of predicted due date (expected date of
confinement; EDC); about 4% deliver on the exact date
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 17th week after conception; 3 of them, any
one of which can confirm pregnancy
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 3rd 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 1st 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 2nd 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 3rd 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 2nd trimester), greatest amount of fetal growth
occurs; fetus is now 6" (15 cm) long; lower body is growing increasingly larger
B. During 5th month, halfway point of pregnancy, fetus weighs ~1 lb (454 g) & is
~12" (30 cm) long; it sleeps, wakes & has a preferred body position
C. During 6th month, fetus grows ~2" (5 cm) & gains another pound
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 7th 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 8th month, fetus weighs ~5 lb, 4 oz (2384 g) & ~20" (51 cm) long
1. During 8th & 9th months, skin redness lessens & wrinkles begin to disappear as
fetus begins to gain ~0.5 lb (227 g) a week
2. Nails reach end of fingers & toes; fetus's actions become limited due to its tight fit
in uterus
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
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
1. Candidates watched closely during pregnancy for signs of possible risk
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 low-risk pregnancies
III. Prenatal care – typically consists of monitoring fetal development, screening for highrisk pregnancy & educating those involved about pregnancy & childbirth
A. For most normal pregnancies, 10 –12 prenatal care visits starting by 6th – 10th 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
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 weight
E. In summary, extra nutrients needed in pregnancy & wide variety of foods needed to
provide them
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
1. Studies to date do not, however, support these concerns
B. To ensure safety of both mother & baby, pregnant women should follow exercise
guidelines of Amer. College of Obstetrics & Gynecology (ACOG)
1. Before exercising during pregnancy, woman should consult her physician or nurse
midwife
2. Conditions that are contraindications to exercise during pregnancy: cardiac disease,
history of 3 or more spontaneous abortions (miscarriages) abnormal bleeding
3. If woman sedentary before pregnancy, should not try to do strenuous aerobic
exercise program; instead, use walking program or one specifically for pregnant
women
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 25th 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. 2nd 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 1st 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
C. Despite the fact that hormones account for & influence sexual differences, males &
females produce the same ones (estrogens, progesterones – female; androgens – male)
1. Males & females produce all 3 but they differ in the amounts they produce
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
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 is thought to be oxygen
deprivation (not proved)
3. Cyanide in smoke may cause vitamin depletion – to detoxify cyanide, mother's
body uses vitamin B12 & essential sulfur amino acids, thus depriving fetus of these
nutrients
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
E. Surgeon General recommends that pregnant women avoid use of alcohol during any
pregnancy stage since it ups risk of prematurity, low birth weight & congenital defects
VI. Cocaine
A. CDC study (2003) – cocaine use starts at a young age; 7.2% of 9th graders report
having used cocaine at least once in their lives
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
C. Research suggests that the testes may be damaged in male fetuses exposed to cocaine;
both male & female fetuses may have chromosomal abnormalities caused by exposure
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
C. Heroin use during pregnancy also associated with jaundice, respiratory distress
syndrome, low birth weight, growth retardation, birth defects & infant death
VIII. Steroids – prescribed drugs: sex hormones & other specific chemicals (cortisol,
prednisone) used to treat kidney inflammations & tissue damage due to rheumatic fever &
other 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 18th week of
gestation
B. Also ~35% of exposed women exhibit benign vaginal epithelial cell changes
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
A. Women who take oral contraceptives are advised to stop them for a few months before
trying to conceive
B. This ensures that body's hormones are in natural balance before pregnancy begins
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 3rd or 4th 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
HIV-positive & may contract AIDS
V. Syphilis – an STI; a common cause of stillbirth & can infect fetus when spirochetes
cross the placenta
A. Infected fetus may show signs of syphilis at birth or may appear normal until
adolescence, when signs of late syphilis appear
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
B. Less commonly, fetus may be infected through placenta while still in utero
C. Woman with history of genital herpes will be followed closely from 32 weeks of
gestation until delivery
VIII. Chlamydia – another STI; caused by intracellular parasite (Chlamydia trachomatis)
A. Infants born to mothers with Chlamydia infections have 70% chance of acquiring
either inclusion conjunctivitis (eye infection) or chlamydial pneumonia during
delivery
B. All pregnant women should be screened for Chlamydia at first prenatal visit
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
B. If pregnant woman has genital warts that are large, they may interfere with birth
process, requiring a cesarean delivery
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
1. In time, Rh- cells are replaced by Rh+ ones that baby normally makes
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 16th 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
C. Sex & exact age of fetus can be determined in this way although it is rarely done for
this alone because of the potential risk
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
B. Plastic catheter is passed through vagina into uterus to the villi
C. Certain defects like those of neural tube not detectable with this technique; if this is
suspected, amniocentesis is needed
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
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 become hypertensive 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)
C. Eclampsia – refers to preeclampsia events, plus convulsions or coma, & can be
fatal; at present, the causes of preeclampsia & eclampsia are unknown
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 the 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 (opened to 4 in or 10 cm across)
2. Stage II –period from full cervical dilation through birth of the child; it can last
from a few minutes to 2 hours in normal delivery, though the longer time is more
common
3. Stage III – period from infant's birth to delivery of placenta or afterbirth (usually
taking up to 1/2 hour)
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
C. Medical attendants monitor the fetal heartbeat regularly with stethoscope on mother's
abdomen & perform vaginal examinations periodically
1. Electronic fetal monitor is used to assess fetal heart rate – doc attaches electrode to
woman's abdomen & electrocardiographic impulses are transmitted to paper
D. If anesthesia is used to reduce or eliminate pain of contractions, it is administrated
late in first stage or in second stage
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 the head, of the 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. Forceps is tool designed to deliver baby's head & is used to gain traction & to rotate
baby; must be used carefully since they exert force & can cause fetal damage
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
C. If episiotomy has been performed, it is repaired after placenta is delivered
V. Drugs used in childbirth
A. Anesthetics inhibit perception, not just of pain, of touch & all other sensations in
mother
1. General anesthetics, which put people to sleep, not only affect mother but cross
placental barrier & reach fetus
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 anesthetize area of buttocks, perineum & inner
thigh (area that literally sits on saddle)
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
1. Spinal anesthesia can cause headache, nausea, vomiting & a drop in blood
pressure
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
1. Try to make external environment as much as possible like uterine environment so
newborn not shocked by rush of extreme sensation (cold air, harsh light, loud
noise)
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
E. Still, many mothers & babies would die without surgical intervention
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
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
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
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
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
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
1. Woman with no medical problems can continue to have kind of sexual & sensual
life she had before pregnancy
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:
B. Necessity for free-flowing sexual communication, both trustful & honest, cannot be
stressed enough
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
A. This is to make sure that vulva has healed if there was a tear or episiotomy & to allow
time to discuss choice of birth control method
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
C. By 4th month after conception, gender of fetus is clearly identifiable by external
genitalia
D. Androgen presence/absence decides if certain tissue piece becomes:
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 are present but tissues are insensitive to
testosterone produced by fetal testes is called testicular feminizing syndrome
1. This is most common form of hermaphroditism, condition in which organs of both
genders are present
II. Differentiation between true hermaphrodites & pseudohermaphrodites – either type is
treated with hormonal therapy, surgery & counseling
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 7th month of fetal development
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
B. May be complicated by an inability or unwillingness to adopt
C. While adoption may relieve stress of wanting to raise children, it may not relieve
stress related to infertility
II. Types of infertility
A. Primary infertility – inability to conceive despite having unprotected intercourse for at
least one year; estimated that 10 – 15% of couples experience primary infertility
B. Secondary infertility – inability to conceive despite having unprotected sexual
intercourse for at least one year & having previously conceived
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
A. ~1% of men become infertile after getting mumps
B. People with sickle cell disease have higher infertility rates
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 a 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
C. Man-on-top coital position increases chances of conception since cervix drops into
seminal pool
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 – man ejaculates in cup (masturbation); ejaculate tested to determine
sperm number present, their motility, fructose amount (sperm nourishment) in semen
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 – high-frequency sound waves are transmitted & reflected by
internal organs & structures; detailed outlines of reproductive system obtained
I. Hysteroscopy – uterus expanded with CO2 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 20th century, advanced reproductive technologies have been developed to
assist infertile couples in conceiving
A. First American baby conceived in vitro was born in December 1981
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
1. Sometimes women find out that all embryos are developing into fetuses & choose
procedure called selective abortion; ≥1 fetuses aborted to give rest a better chance
2. In many clinics, more eggs harvested than needed for single cycle & are fertilized;
they are then frozen so they can be used for future IVF procedures
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
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
1. With AID, mothers at least are biological parents of offspring