Page 125-161, 36 pages Page 1 of17
Chapter 6: Conception, Pregnancy, and Childbirth
Sperm Meets Egg: The Incredible Journey
• On day 14 of the menstrual cycle, a woman ovulates. The
ovum is picked up by fimbriae and enters the fallopian tube. If
fertilized, it moves to the uterus using cilia; if not, it
• Sperm is deposited in the vagina through ejaculation or
assisted insemination. The sperm has already travelled
through the seminiferous tubules, epididymis, vas deferens,
ejaculatory duct, and urethra!
• The sperm has a head, midpiece, and tail, about 60 micrometres in length. The head contains DNA in
the nucleus, as well as RNA that directs early embryonic development, and many proteins.
• The acrosome, a chemical reservoir, is located in the head. The mid-piece contains many mitochondria
to provide energy, used to lash the tail back and forth in flagellation to propel the sperm forward.
• A typical ejaculate of 3mL contains about 200 million sperm, only 2000 of which reach the fallopian
tube. Sperm swim at 1-3cm per hour, although they may arrive at the egg within 1.5hrs due to aid of
• The egg is surrounded by a thin, gelatinous layer of zona pellucida. Sperm secrete the enzyme
hyaluronidase produce by the acrosome to dissolve the zona pellucida, and thus penetrate the egg.
• The fertilized zygote will travel down the fallopian tube and start dividing after 36hrs. After 5-7 days, it
implants itself in the uterine lining. It remains a zygote for the first 2 weeks, an embryo for 2-8wks, then a
Improving the Chances of Conception: Making a Baby
• Time of ovulation can be determined with a basal body temperature chart, taking temperature every
morning immediately upon waking. Ovulation is indicated by a rise in temperature the day after it occurs
• Cervical mucus and sympto-thermal methods can also be used
• Sperm live in the woman`s body for 5 days, and the egg is capable of being fertilized for 12-24hrs after
ovulation. Thus, intercourse should be timed right at ovulation or 1-2 days before.
• It takes 24hrs to manufacture 200 million sperm, and maintaining a high sperm count is important for
fertilization. It is thus best to have intercourse every 24-48 hours around 4 times during the week of
• For conceiving, the best position for intercourse is with the woman on her back to keep ejaculate in the
vagina. The woman should remain on her back for half an hour to an hour after to give the sperm a
chance to swim up into the uterus.
• Douching with commercial preparations or acidic solutions should be avoided. Lubricants and
suppositories may also kill sperm or block their entrance.
DEVELOPMENT OF THE CONCEPTUS
• Pregnancy is not always a harmonious relationship between the conceptus and pregnant woman, with
both competing for nutrients and the development of conditions that can be a serious risk to both.
• Gestational diabetes occurs when the body is not able to make all the insulin it needs during
pregnancy, and pre-eclampsia occurs in the 3 trimester with sharp increase in BP, proteinuria, and
• Pregnancy lasts for about 38 weeks, divided into three trimesters: months 1-3, 4-6, and 7-9 Page 125-161, 36 pages Page 2 of 17
The Embryo & Its Support System
• During the embryonic period, there is major organ system development. The ectoderm forms the
nervous system and skin. The endoderm forms the digestive system and respiratory system. The
mesoderm form muscles, skeleton, connective tissues, reproductive, and circulatory systems.
• Development proceeds in a cephalocaudal order, with head first and lower body last.
• The trophoblast develops into support tissues, such as the placenta which nurtures the embryo’s
growth. It is the site of exchange of substances between the mother and fetus’s blood – they do not mix,
but exchange through a membrane barrier at the villi projections.
• Oxygen, nutrients, carbon dioxide, and waste products are exchanged. Some viruses, disease-causing
organisms, and drugs can also cross the placental barrier.
• The placenta secretes estrogen and progesterone, leading to physical symptoms of pregnancy. It also
makes human chorionic gonadotropin (hCG), which is detected in pregnancy tests.
• The umbilical cord connecting the fetus to the placenta forms during the 5 week. It contains three
blood vessels (2 arteries, one vein) and is about 20 inches long.
• The fetus is surrounded by the chorion and amnion. The amnion is filled with amniotic fluid, a watery
substance in which the fetus floats; it maintains a constant temperature and acts as cushioning
Week 3-4 Development of the head and
Nervous system begins to form
Week 5 Formation of umbilical cord
Week 4-8 External body parts develop: eyes,
ears, arms, hands, fingers, legs, feet,
Liver, lungs, pancreas, kidneys and
intestines form with limited functioning
Week 14 Fetal movement, or quickening
Week 18 Fetal heartbeat
Week 24 Fetus sensitive to light and sound in
Week 28 Fat deposits form
Week 29-Birth Rapid growth
• At the end of the week 12 (1 trimester), the fetus is unmistakably human having developed most major
organs systems and recognizable human features. It is about 10cm long and 19grams; from this point
on, development consists mainly of enlargement and differentiation of structures already present.
• In the 7 month, the fetus turns to assume a head-down position. If this does not occur, there will be a
breech presentation during delivery.
• The average full-term baby is 3.5kg and 50cm long.
Stages of Pregnancy
First Trimester (Week 1-12)
• Symptoms of Pregnancy: The first symptom is usually a missed menstrual period, although there are
many other reasons for a woman to have a late or missed period (illness, stress). A woman may continue
to explain cyclic bleeding or spotting during pregnancy. Page 125-161, 36 pages Page 3 of 17
• Basal body temperature, after rising during ovulation, stays up during pregnancy. This is from the
increased progesterone manufactured by the corpus luteum and placenta.
• Other symptoms include breast tenderness, nausea and vomiting, frequent urination, and fatigue.
• Pregnancy Tests: Early detection of pregnancy is necessary for good prenatal care; if the woman does
not want to carry the pregnancy, it is also safer to perform abortions early.
• Most pregnancy tests are immunologic tests detecting the presence of hCG in the urine. These tests
are 98-99% accurate, although they may produce a false negative if done too early (typically 7 days after
• Beta-hCG radioimmunoassay tests detect the presence of beta-hcG in the blood, but is much more
expensive and only available at hospital or clinic laboratories. Most home pregnancy tests use urine hcG,
and provide convenience and privacy of testing; however, they have higher rates of error.
• Presumptive signs include amenorrhea, breast tenderness, and nausea. Probable signs include
pregnancy test results. Positive signs which are definite indications of pregnancy are: 1) fetal heart
beat, 2) active fetal movement, and 3) detection of fetal skeleton by ultrasound. These signs are detected
in the 4 month.
• The expected delivery date is calculated using Nägele’s rule: first day of last menstrual period, subtract
three months, add seven days, add one year. Ultrasounds are used to revise the due date.
• Physical Changes: Most physical changes arise from increase in estrogen and progesterone.
• Breasts swell and tingle due to development of mammary glands, with areola darkening.
• Need to urinate more frequently due to effects on the adrenal gland, which causes more water to be
• Morning sickness with nausea, vomiting, and revulsion to food; this may be evolutionarily adaptive for
pregnant women to avoid toxic chemicals; 25% do not experience any vomiting.
• Vaginal discharges increase due to hormones, and also change in chemical composition.
• Progesterone has sedative effect, causing fatigue and sleepiness.
• Psychological Changes: A woman’s emotional state during pregnancy is not like stereotypes; it varies
according to her attitude toward the pregnancy (did she desire the pregnancy?), social class (low income
associated with depression), and availability of social support (buffer against stressful events).
• High stress at 30 weeks is associated with increased risk of still birth.
Second Trimester (Week 13-26)
• Physical Changes: Fetus movements can be felt at 4 month, with quickening.
• The expanding belly may be seen as a symbol of womanhood, or may cause resentment due to weight
• Symptoms of first trimester, such as morning sickness, disappear. Physical problems now include
constipation, nosebleeds (increased blood volume), and edema.
• Breast development have completed for nursing; from 19 week, thin watery fluid called colostrum
may begin to be secreted, but there is no milk produced yet.
• Psychological Changes: Discomforts of first trimester past, while tensions associated with labour
have not yet arrived; fears of miscarriage also decrease with fetal movement.
• Women who have had previous pregnancies experience more distress, perhaps reflecting demands of
care of other children in addition to being pregnant.
Third Trimester (Week 27-38)
• Physical Changes: The woman is increasingly aware of her size and the more active fetus. The large
size of the uterus puts pressure on other organs, causing discomfort – lungs causing shortness of breath,
stomach causing indigestion, heart strained due to increased blood volume. Page 125-161, 36 pages Page 4 of 17
• Weight gain ranges from 6.5-18kg (15-40 pounds), with women who are slim gaining relatively more.
This includes the fetus, placenta, amniotic fluid, enlargement of uterus and breasts, and additional fat
• Balance is disturbed due to uneven distribution of weight, and waddling can lead to back pains.
• Braxton-Hicks contractions are painless uterine contractions not part of labour. They may help
strengthen the uterine muscles in preparation for labour.
• 2-4 weeks before delivery, the fetal head drops into the pelvis in engagement; this occurs during labour
for women who have had children before.
• Psychological Changes: First-time mothers report significant increase in dissatisfaction with
husbands from the 2 to 3 trimester. Higher levels of affection and social support decrease pregnancy
complications and anxiety.
The Father’s Experience in Pregnancy
• Men may experience pregnancy symptoms including indigestion, nausea, and appetite changes in
couvade syndrome, perhaps due to hormonal changes. This is due to high levels of prolactin.
• In some cultures, there is a couvades ritual where the men retires to bed while his wife is in labour,
suffering all the pains of delivery as she does. This is practiced in parts of Asia, South America, and
• Many men are involved in preparing for fatherhood by attending parenting classes, talking to other
fathers, and daydreaming about the baby.
• A strong father-infant bond depends on the father’s responsiveness to the infant. Men with higher
responsiveness have higher prolactin prenatally, and lower testosterone postnatally. Joint activities
between partners also contributes to the partner bond, providing a foundation for the arrival of the child.
Sex during Pregnancy
• Many couples are concerned about safety of a pregnant woman having sexual intercourse, particularly
in later stages. Traditionally, physicians believed PIV intercourse may cause an infection, or precipitate
labour prematurely or cause a miscarriage.
• Today, in a normal, healthy pregnancy, intercourse can continue safely until four weeks before delivery.
In fact, recent intercourse and orgasm is associated with decreased risk of preterm birth.
• There is decline in intercourse during the first, and especially the third trimesters. Some women report
increased arousal in the 2 trimester.
• During later stages, the side-to-side position is probably most suitable. There are also many ways of
experiencing pleasure and orgasm besides vaginal intercourse.
Nutrition during Pregnancy
• The mother needs to have a good diet for energy, protein, vitamins, and minerals; if her diet is
inadequate, she has higher risk of developing diseases and of bearing a child with low birth weight.
• On the other hand, overweight women also have increased risk of hypertension, gestational diabetes,
and C section; the fetus has increased risk of spina bifida, cleft palate, and hydrocephaly.
• Folic acid is important for growth and prevention of anemia and fatigue; iron is necessary for increased
circulating blood for the fetus; calcium is needed to prevent increased BP, muscle cramps, nerve pains,
sleeplessness, and irritability; calcium and magnesium deficiencies are associated with premature birth.
Substances That May Result in Birth Defects
Substances Taken during Pregnancy
• Teratogens are substances that produce fetal defects. This includes alcohol, which passes through the
placenta and circulates through the fetus to cause retardation of fetal development. Page 125-161, 36 pages Page 5 of 17
• Fetal alcohol spectrum disorder covers all outcomes associated with any alcohol exposure during
pregnancy, with effects being dose-dependent. Fetal alcohol syndrome refers to the most serious
pattern of malformations, with growth deficiencies including a small brain, joint, limb and heart
malformations, and cognitive impairments.
• According to the Public Health Agency of Canada, there is no safe amount of alcohol during pregnancy.
• Tobacco use retards fetal growth and increases risk of disability and death – including low birth weight,
premature birth, CV anomalies, and asthma.
• Steroids, antihistamines, excessive vitamin A, D, and K, caffeine, antidepressants, cocaine, and many
Dads & Drugs
• Drugs taken by men before conception may also cause birth defects due to damage to sperm.
• Marijuana causes decreased sperm count, damaged sperm, and reduced fertility.
Viral Illness during Pregnancy
• Viruses can cross the placenta and cause considerable harm, especially during the first trimester. With
rubella contracted in the first month, there is a 50% chance the infant will be born deaf, have cognitive
deficits, cataracts, or congenital heart defects; this declines to 10% in the 3 month.
• Herpes simplex is transmitted by direct contact with the sore during delivery. This can be prevented by
• HIV can be passed on during pregnancy, delivery, or after birth through breast milk. The infected
mother can take antiretrovirus drugs such as AZT to decrease risk of perinatal transmission.
• Defects include genetic defects (PKU) and chromosomal defects (Down syndrome). About 25% of
miscarried fetuses are malformed, with the cause of most defects unknown.
• Amniocentesis involves inserting a fine tube through the abdomen and removing some amniotic fluid
for analysis. This can diagnose most chromosomal abnormalities, biochemical disorders, and sex-linked
disorders. It is performed between weeks 13-16.
• Amniocenesis itself includes some risk, so it should only be performed on women who have a high risk
of bearing a child with a birth defect. This includes women who already have children with birth defects,
who are carriers, or who are over 35 years old.
• Chorionic villus sampling (CVS) can be done in the first trimester in weeks 9-11. It can be done
transcervically with a catheter inserted into the uterus, or transabdominally with a needle through the
abdomen. A sample is taken from the chorionic villi to be analyzed. The risk of fetal loss is 1-1.5%.
The Beginning of Labour
• Symptoms include discharge of a small amount of blood mucus, which was the plug present in the
cervical opening during pregnancy that prevented germs from entering.
• In 10% of women, the membranes continuing the amniotic fluid ruptures, creating a gush of warm fluid.
Labour usually begins within 24hrs after this event. More commonly, the amniotic sac does not rupture
until the end of the first stage of labour.
• Braxton-Hicks contractions may increase before, and be mistaken for, labour; they are much more
• Progesterone-Withdrawal is proposed to initiate labour, as progesterone inhibits uterine contractions.
Stages of Labour
• The process of parturition, or child-birth, is divided into 3 stages that vary in length between
individuals. Page 125-161, 36 pages Page 6 of17
• Uterine contractions lead to effacement (thinning out) and dilation (opening up) of the cervix, with
dilation continuing until 10cm (4 inches).
• First-stage labour itself is divided into early, late, and transition. In early first-stage, contractions are
spaced far apart, by 15-20mins with each contraction lasting 45sec to 1min. This stage is fairly easy.
• In late first-stage, the cervix is dilated to 5-8cm, with more frequent and intense contractions.
• The final dilation to 8-10cm occurs in the transition phase, which is both short and difficult with very
strong contractions, and women reporting pain and exhaustion.
• The first stage can last anywhere from 2-24hrs, averaging 12-15 for a first pregnancy and 8hrs for later
ones. Women usually go to the hospital when contractions are 4-5mins apart.
Second-Stage Labour: Delivery
• Second-stage labour begins when the cervix is fully dilated, and the baby begins to move into the birth
canal. It lasts from a few minutes to a few hours.
• Many women feel an urge to push or bear down, helping the baby out. Crowning occurs when the
baby’s head has traversed the vagina and becomes visible. Physicians may now perform an episiotomy,
an incision in the perineum just behind the vagina, to deliver the baby more easily (now only performed in
21% of deliveries).
• Episiotomies are performed to reduce the severity of perineal lacerations, reduce post-delivery pain and
medication use, and prevent impaired sexual functioning. However, research shows these benefits do
not actually result from episiotomies and suggest it is done for the doctor’s convenience.
• Perineal massage may reduce the risk of tears in the perineum, during childbirth and in the weeks
• The baby is finally delivered, with blood flowing to the lungs and a flap closing between the heart atria.
The baby changes from a bluish colour to a healthy, pink hue. The umbilical cord is clamped and cut off
with the stub gradually drying and falling off.
• During third-stage labour, the afterbirth of placenta and fetal membranes are expelled with several
Caesarean Section (C-Section)
• Caesarean Section is a surgical method of delivering a baby, by an incision in the abdomen through
• This may be required when normal vaginal birth is impossible or undesirable, such as when the baby is
too large or the mother’s pelvis too small, if the labour has been very long and hard, if the cervix is not
dilating, if the umbilical cord prolapses (comes out of cervix before the baby), if there is an Rh
incompatibility, if there is excessive bleeding, or if there is placenta previa where the placenta is close to
or covering the cervix.
• It is not true that once a woman has delivered by Caesarean, she must have all subsequent deliveries
by this method. Vaginal births after Caesarean (VBAC) are 63% successful.
• 26% of Canadian births are by Caesareaen section. There is concern about high and increasing C-
section rates, as women are at higher risk of severe illness after delivery.
• Higher rates of use may be due to older maternal age (labours would be more difficult, necessitating C-
sections), increased use of fetal monitors (can warn physician of fetal distress), and more women
• C-sections may be elective for their benefits without clear medical reasons, such as decreased risk of
urinary incontinence, lack of fear and pain, and protection of fetus against birth-related injuries. Page 125-161, 36 pages Page 7 of17
• Rate of C-sections decreases with prenatal education, tightened guidelines for C-sections, and women
being encouraged to remain active during labour.
• Programs attempt to eliminate pain of childbirth by providing education (removing fear of the unknown)
and teaching relaxation techniques (to eliminate tension).
• The Lamaze method involves two basic techniques of relaxation and controlled breathing, helping
conserve energy and avoiding tension that precipitates pain. Controlled breathing helps during
• Effleurage involves a light, circular stroking of the abdomen with fingertips
• Women may be accompanied during training and childbirth by a coach, to help the woman learn
techniques and use them during labour. The coach times contractions, checks relaxation, gives
feedback, and provides encouragement and moral support. This particularly allows the partner to play an
• Doula provide physical and emotional support without clinical or medical tasks.
• Prepared birth does not ban the use of anaesthetics – the goal is to teach each woman the techniques
she needs to control her reactions to labour so she can not need an anaesthetic, but can use it if she
• Training decreases length of labour, incidence of birth complications, use of anaesthetics, and
increases self-esteem, sense of control, and tolerance for pain.
• Primipara is a woman having her first baby. They often have discrepancies between their positive
expectations and actual outcomes; while preparation helps women prepare, it does not eliminate pain or
Use of Anaesthetics
• Today almost all births occur in hospitals, with routine use of anaesthetics. Tranquilizers such as Valium
or narcotics may be used to decrease pain, and barbiturates to put the woman to sleep and for amnesic
• Regional and local anaesthetics numb specific areas of pain, such as pudendal (vulvar) blocks, and
spinal blocks that numb the external genitals and waist-down birth area respectively.
• The caudal block and epidural anaesthesia numb the belly to thighs; epidurals used in 45% of births.
• Anaesthetics may be passed through the placenta to the infant, depressing the infant’s CNS. They also
prevent the mother from taking on as active of a role in pushing the baby during labour, even prolonging
Home Birth vs. Hospital Birth
• Advocates of home birth suggest the hospital atmosphere is stressful, and detracts from a joyous
experience. The association of hospitals with illness, and its use of intervention procedures such as
episiotomies may also be objectionable. Home births may be more relaxes with more support persons
• For uncomplicated pregnancies, home births are as safe as hospital deliveries. If emergency medical
procedures are necessary, home births may be dangerous. Physicians or midwives must be a part of the
• Hospitals may have birthing rooms with a more relaxed atmosphere, while being accessible to
emergency equipment if needed.
Use of Midwives
• In Canada, only 6% of women receive prenatal care from a midwife, although it is becoming a more
independent, recognized, and regulated profession (and thus more publicly funded). Page 125-161, 36 pages Page 8 of 17
• To be registered, a midwife must show that she is able to deliver competent care as a primary caregiver
to a low-risk woman.
• Midwives provide early care from early pregnancy to 6 weeks postpartum, making for continuity of care
and a personal relationship with the family. Prenatal visits are typically 45 minutes long, providing
detailed information for the family to make informed decisions about their care and birth experience.
Lastly, there is a choice of birth place in either a home or hospital/birthing centre.
• Midwives support birth as a normal physiological process, but are also trained to manage emergencies
and to ask for referrals to specialists if complications arise outside their scope of practice.
• Women who have delivery performed by a midwife are most satisfied with their birth experience.
AFTER THE BABY IS BORN: POSTPARTUM PERIOD
• With the placenta expelled, levels of estrogen and progesterone drop sharply, before gradually
returning to normal over a few weeks to months. However, hormones associated with breastfeeding
• Women often stay in hospital for 2-3 days after delivery, or 4-5 days after a C-section
• Women may experience postpartum blues with mood swings, and periods of feeling depressed,
irritable, and crying. These symptoms tend to be most intense 1 week postpartum, and lessen after 2
• Postpartum depression is more severe, characterized by depressed mood, insomnia, tearfulness,
feelings of inadequacy, and fatigue; this affects 8-15% of women and lasts for 6-8 weeks.
• Postpartum psychosis is the most severe disturbance with later symptoms including disorganized
behaviour, mood swings, delusions, and hallucinations, affecting 0.1-0.2% of women.
• Stressful factors contributing depression include the hospital stay itself, the exhausting task of caring for
a newborn infant, and the lack of sleep or rest. Other risk factors include personal or family history of
psychiatric disorder, unwanted pregnancy, serious complications, and lack of support.
• Women experiencing multiple births have higher postpartum depression symptoms than mothers of
• Physical factors of body changes, declines in hormone levels, and stress of delivery also contribute
• Depression improves with antidepressants, psychotherapy, support, and nurse home visits.
• Fathers may also experience postpartum blues.
Attachment to the Baby
• The mother’s attachment to the infant begins before the baby is both, with pregnancy part of the
psychological preparation for motherhood and feelings of nurturance growing throughout
• There is little evidence that there is a sensitive period for bonding in the minutes and hours after birth;
mothers giving birth by C-section and adoptive parents fo