conception, pregnancy, and childbirth
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Conception, Pregnancy, and Childbirth. Chapter 11. Learning Objectives. Conception Infertility Pregnancy Prenatal Development Childbirth The Postpartum Period. Conception. Conception. Conception. Conception. Infertility. Infertility. Infertility. Infertility. Infertility. - PowerPoint PPT PresentationTRANSCRIPT
CONCEPTION, PREGNANCY, AND CHILDBIRTH
Chapter 11
Learning Objectives• Conception• Infertility• Pregnancy• Prenatal Development• Childbirth• The Postpartum Period
Conception
• Zygote is a fertilized ovum• Each ejaculate contains an average of 200 to
400 million sperm• Ovum secretes a chemical that attracts sperm• Fertilization normally occurs in a fallopian tube• Ovum is surrounded by zona pellucida which
must be penetrated by sperm to fertilize it• Sperm secrete the enzyme hyaluronidase,
which briefly thins zona pellucida, enabling penetration
Union of a sperm cell and an ovum
Conception
• Ova carry X sex chromosomes• Sperm carry either X or Y sex chromosomes• Girls are produced from union of 2 X• Boys are produced from union of an X and a Y• Y sperm appear to be faster swimmers• Male fetuses more likely lost in spontaneous
abortion, which helps balance the sexes• Spontaneous abortion is the loss of pregnancy,
often in the first month, and sometimes before the woman knows she’s pregnant
Union of a sperm cell and an ovum
Conception
• Ovum can be fertilized for 4-20 hours after ovulation
• Sperm are most active within 48 hours after ejaculation
• Ways to predict ovulation• Basal body temperature (BBT) chart• Analyzing urine or saliva for luteinizing
hormone• Tracking vaginal mucus
• Coitus in the male-superior position
Optimizing Chances
Conception
• Reasons to select• Personal preference• Family balancing• Avoidance of sex-linked diseases
• Folklore provides many techniques• Selective abortion• Infanticide• Sperm-separation procedures• Pre-implantation genetic diagnosis (PGD)
• Currently the most reliable sex-selection method
Selecting the Sex of Your Child
Critical Thinking
Sex selection raises many moral and ethical questions. Many people wonder whether people have the “right” to select the sex of their children.
Where do you stand on the issue? Why?
Infertility
Inability to
conceive a child
• Term usually not applied until the failure has persisted for more than a year
• Women over the age of 35 are advised to seek help after 6 months of trying
• About 15% of American couples experience infertility.
Infertility
Male Fertility Problems
• Low sperm count• Irregularly shaped sperm• Low sperm motility (self-
propulsion)• Chronic diseases (diabetes,
infectious diseases)• Injury to the testes• Autoimmune response
(antibodies deactivate sperm)• Pituitary imbalance and/or
thyroid disease
Infertility
Male infertility solutions include
• Microsurgery• Artificial insemination• Introduction of sperm into
the reproductive tract through means other than sexual intercourse
Infertility
Female Fertility
Problems
• Irregular ovulation, including failure to ovulate (10-15%)
• Obstructions or malfunctions of the reproductive tract, such as blocked fallopian tubes
• Endometriosis• Endometrial tissue is sloughed
off into the abdominal cavity rather than out of the body during menstruation
• Declining hormone levels
Infertility
Female infertility solutions include
• Fertility drugs• Laparoscopy (for detection & treatment)• In vitro fertilization (IVF)
• Mature ova are surgically removed from an ovary and placed in a laboratory dish along with sperm
• Gamete intrafallopian transfer (GIFT)• Sperm and ova are inserted into a
fallopian tube to encourage conception
• Zygote intrafallopian transfer (ZIFT)• Ovum is fertilized in a laboratory dish
and then placed in a fallopian tube
Infertility
Female infertility
solutions include
• Donor IVF• Ovum is taken from one woman,
fertilized, and then injected into the uterus or fallopian tube of another woman
• Embryonic transfer• Woman volunteer is artificially
inseminated by the male partner of the intended mother
• Embryo is removed and inserted within the uterus of the intended mother
• Intracytoplasmic sperm injection• Single sperm is injected directly into an
ovum
Infertility
Female infertility solutions include
• Surrogate motherhood• Woman is impregnated
through artificial insemination with the sperm of a prospective father
• Carries the embryo and fetus to term
• Gives the child to the prospective parents
• Adoption
Pregnancy
Early Signs of Pregnancy
• Missing a period• It is not a reliable indicator.
• Basal body temperature remains high for about three weeks after ovulation
Pregnancy
Early Effects of Pregnancy
• Tenderness of the breasts• Morning sickness• Nausea, aversions to specific foods, and
vomiting• May occur throughout the day• Usually subsides by about the twelfth week of
pregnancy• May experience more fatigue and frequent
urination
Pregnancy
Miscarriage
• Spontaneous abortion• Causes include chromosomal defects in the embryo or fetus
• More common in older pregnant women
Pregnancy
Sex During Pregnancy
• Given a normal pregnancy, coitus is safe throughout pregnancy until the start of labor
• A pregnant woman’s interest in sex may vary • Tends to be higher during the second
trimester compared to the first and third
Pregnancy
Psychological Changes During Pregnancy
• Reflect desire to be pregnant, her physical changes, and her attitudes toward these changes• May also depend on the trimester of
pregnancy• Men, like women, respond differently to
pregnancy
Prenatal Development
Calculate delivery date by using Naegele’s rule
Use date of first day of the last menstrual period
Add 7 days
Subtract 3 months
Add 1 year
Prenatal Development
Figure 11.3. The ovarian cycle, conception, and the early days of the germinal stage (p. 306).
Stages of Prenatal DevelopmentGerminal stage
First two weeks of pregnancy
Period before implantation in the uterus
Also called the period of the ovum
Blastocyst Embryo is a sphere of cells surrounding a cavity of fluid
Embryonic disk is a platelike inner part of the blastocyst
Differentiates into the ectoderm, mesoderm, and endoderm of the embryo
Trophoblast is the outer part of the blastocyst
Develops into the amniotic sac, placenta, and umbilical cord
Stages of Prenatal DevelopmentEmbryonic stage
Lasts from implantation through the eighth week
Differentiation of the major organ systems occurs
Development of the embryo follows two trends
Cephalocaudal – from the head downward
Proximodistal – from the central axis of the body outward
Stages of Prenatal DevelopmentEctoderm• Outermost cell
layer of the embryo from which skin and nervous system develop• Neural tube –
hollow area in the blastocyst from which the nervous system will develop
Endoderm• Inner layer
of the embryo from which the lungs and digestive system will develop
Mesoderm• Central
layer of the embryo from which the bones and muscles develop
Stages of Prenatal DevelopmentAmniotic sac• The sac containing
the embryo/fetus• Amniotic fluid
• Suspends and protects the embryo/fetus
Placenta• Organ connected to
fetus by umbilical cord • Relay station between
mother and embryo/ fetus; allows for the exchange of nutrients and wastes
• Secretes hormones that • preserve pregnancy• stimulate uterine
contractions that induce childbirth
• help prepare breasts for breastfeeding
Stages of Prenatal Development
Figure 11.4. Human embryos and fetuses (p. 307).
Stages of Prenatal DevelopmentFetal stage
Begins by the ninth week and continues until birth
Fetal movements can be felt
Age of viability is the age at which a fetus can sustain independent life
During the seventh month, the fetus typically turns upside down in the uterus
Cephalic presentation
Emergence of the baby head first from the womb
If not, may be in a breech presentation
Can complicate premature birth
Environmental Influences on Prenatal Development
• Malnutrition• Obesity
Mother’s diet
• Teratogens • Environmental
influences or agents that can damage an embryo or fetus
• Critical periods of vulnerability• When embryo or
fetus is vulnerable to the effects of a teratogen
Maternal diseases and
disorders
Environmental Influences on Prenatal Development
Figure 11.5. Critical periods (p. 310).
Prenatal Development
Rubella (German measles)• Viral infection that can
cause mental retardation and heart disease in an embryo
Syphilis• Sexually transmitted
disease caused by a bacterial infection
• May cause miscarriage or stillbirth or be passed along to the child in the form of congenital syphilis
HIV/Acquired immunodeficiency syndrome (AIDS)• Destroys white blood
cells in the immune system
• Majority of babies born to infected mothers do not become infected themselves
Toxemia• Life-threatening
condition characterized by high blood pressure
Ectopic pregnancy• Fertilized ovum
becomes implanted someplace other than the uterus
Prenatal DevelopmentRh incompatibility• Antibodies
produced by a pregnant woman are transmitted to the fetus and may cause brain damage or death
Drugs taken by the mother (and the father)• OTC• Prescription
Hormones• Diethylstilbestrol (DES)
• An estrogen that was once given to women at risk for miscarriage to help maintain pregnancy
• Suspected of causing cervical and testicular cancer in some children whose mothers used it when pregnant
Vitamins (high doses) Narcotics Tranquilizers
and sedatives MarijuanaAlcohol• Fetal
alcohol syndrome (FAS)Cigarette smoking
• Increases risk of low birth weight, early infant mortality, and intellectual impairments
X-rays
Prenatal Development
• Genetic counseling• Chorionic villus
sampling (10 weeks)
• Amniocentesis (4 months)
• Ultrasound• Parental blood tests• Test of fetal DNA
Averting chromosom
al and genetic
abnormalities
Childbirth
Lightening
Baby’s head drops
into the pelvis, usually
early in 9th month
Braxton-Hicks contractions
So-called false labor contractions that are relatively painless
Prostaglandins
Uterine hormones
that stimulate uterine
contractions
Oxytocin
Pituitary hormone
that stimulates
uterine contraction
s
Stages of Childbirth
First stage
• Uterine contractions efface and dilate the cervix• 4 inches (10 cm)
• Transition• Process during which the cervix becomes
nearly fully dilated and the head of the fetus begins to move into the birth canal
• May last from a couple of hours to more than a day during a first pregnancy and is usually shorter in subsequent births
Stages of Childbirth
Second stage
• Shorter than first stage• Begins when cervix is fully dilated and
baby begins to move into the vagina• Episiotomy may be performed
• Surgical incision in the perineum that widens the birth canal, preventing random tearing during childbirth
• Ends with birth of baby
Stages of Childbirth
Third stage• Placenta is expelled
In the new world
• Once baby is breathing adequately umbilical cord is cut
Stages of Childbirth
Figure 11.7. The stages of childbirth (p. 319).
Methods of Childbirth
Anesthetized childbirth
• General anesthesia• The use of drugs to put people to sleep and eliminate pain• May prolong labor• They cross placental barrier and lower newborn’s
responsiveness• Local anesthesia
• Eliminates pain in a specific area of the body• Decreases newborn’s responsiveness• Little evidence that medicated childbirth has serious, long-
term consequences Figure 11.7. The stages of childbirth (p. 319).
Methods of Childbirth
Prepared childbirth: Lamaze method
• Women are taught to reduce pain by thinking of pleasant images or engaging in breathing and relaxation exercises
• Women attend classes and have a “coach” to help them through the birthing process
• Anesthetics can be used, if needed• Gives women a sense of control over
delivery process Figure 11.7. The stages of childbirth (p. 319).
Methods of Childbirth
Cesarean section• Fetus is delivered through a surgical incision in the abdomen• Mostly without complications• May cause urinary tract infections, inflammation of the uterine wall,
blood clots, or hemorrhaging• Increases rate of pregnancy-related death (4x)• Advised when normal delivery is difficult or is threatening the health or
life of mother or child• Baby is in breech (feet downward) or transverse position (crosswise
birth position), large, mother is infected with HIV or herpes, mother is tired
• Today, about 29% of births are by C-section.• Some view this number as too high
• Can deliver subsequent babies vaginallyFigure 11.7. The stages of childbirth (p. 319).
Birth Problems
Anoxia: Oxygen deprivation
• Can result in brain damage and mental retardation• If prolonged, can result in cerebral palsy and death• Occurs due to constriction of the umbilical cord
Preterm and low-birth weight
children
• Born before 37 weeks of gestation• A weight of less than 5 pounds• Respiratory distress syndrome
• Cluster of breathing problems, responsible for many neonatal deaths
• Usually require monitoring and extra care
Stillbirth
• Baby is born dead• Connected to fetal abnormalities, infection,
maternal medical conditions, and pregnancy complications
• Most cases have no clear cause
Postpartum Period
Maternal Depression• Baby Blues
• Statistically normal• Lasts for about 10 days and does not impair functioning
Postpartum Period
Maternal Depression• Postpartum Depression
• Affects 1 in 5 to 10 women• Persistent and severe mood changes during the postpartum period, involving
feelings of despair and apathy and characterized by changes in appetite and sleep, low self-esteem, and difficulty concentrating
• May result from interaction of biological and psychological factors• Begins 4 weeks post delivery and may linger for weeks or months
Postpartum Period
Breastfeeding vs. Bottle-
Feeding
• About three in five women in the U.S. breastfeed
• It is recommended that women breastfeed for a year or more• It reduces the general risk of infections
and allergies• Prolactin
• A pituitary hormone that stimulates milk production
• Lactation• Production of milk by the mammary
glands
Postpartum Period
Resumption of Ovulation and Menstruation
• Lochia• Reddish vaginal discharge that may
persist for a month after delivery• A non-nursing mother does not resume
menstruation until 2 to 3 months postpartum
• Ovulation typically precedes menstruation
Resumption of Sexual Activity
• Obstetricians usually advise a 6-week waiting period