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Copyright 2008 Allyn & Bacon Conception, Pregnancy, and Childbirth Chapter 11 This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network; preparation of any derivative work, including the extraction, in whole or in part, of any images; any rental, lease, or lending of the program.
Copyright 2008 Allyn & Bacon Conception, Pregnancy, and Childbirth Conception: Against All Odds Infertility and Assisted Reproductive Technology Pregnancy Prenatal Development Childbirth The Postpartum Period
Copyright 2008 Allyn & Bacon Conception: Against All Odds Conception Union of a sperm cell and an ovum Zygote: 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.
Copyright 2008 Allyn & Bacon Conception: Against All Odds 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: loss of pregnancy, often in the first month, and sometimes before the woman knows she’s pregnant
Copyright 2008 Allyn & Bacon Conception: Against All Odds Optimizing the Changes of 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 Additional considerations Coitus in the male-superior position
Copyright 2008 Allyn & Bacon Conception: Against All Odds Selecting the Sex of Your Child(?) Reasons to select: Personal preference Family balancing Avoidance of sex-linked diseases Folklore provides many techniques Selective abortion Infanticide
Copyright 2008 Allyn & Bacon Conception: Against All Odds Selecting the Sex of Your Child(?) Sperm-separation procedures Preimplantation genetic diagnosis (PGD) Is currently the most reliable sex-selection method
Copyright 2008 Allyn & Bacon Infertility and Alternative Ways of Becoming Parents 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.
Copyright 2008 Allyn & Bacon Infertility and Alternative Ways of Becoming Parents Male Fertility Problems Causes include: 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
Copyright 2008 Allyn & Bacon Infertility and Alternative Ways of Becoming Parents Male infertility solutions include: Microsurgery Artificial insemination Introduction of sperm into the reproductive tract through means other than sexual intercourse
Copyright 2008 Allyn & Bacon Infertility and Alternative Ways of Becoming Parents Female Fertility Problems Causes include: Irregular ovulation, including failure to ovulate 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
Copyright 2008 Allyn & Bacon Infertility and Alternative Ways of Becoming Parents 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
Copyright 2008 Allyn & Bacon Infertility and Alternative Ways of Becoming Parents 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
Copyright 2008 Allyn & Bacon Infertility and Alternative Ways of Becoming Parents 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
Copyright 2008 Allyn & Bacon 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
Copyright 2008 Allyn & Bacon Pregnancy Pregnancy Tests Human chorionic gonadotropin (HCG) Hormone produced by women shortly after conception Detected in urine as early as third week of pregnancy Detected in a blood test as early as the eighth day of pregnancy
Copyright 2008 Allyn & Bacon Pregnancy Early Effects of Pregnancy Tenderness of the breasts Morning sickness Symptoms of pregnancy including 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
Copyright 2008 Allyn & Bacon Pregnancy Miscarriage Spontaneous abortion; causes include chromosomal defects in the embryo or fetus More common in older pregnant women 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
Copyright 2008 Allyn & Bacon 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 Sympathetic pregnancy Experiencing of a number of signs of pregnancy by the father
Copyright 2008 Allyn & Bacon Prenatal Development Delivery date may be calculated using Nagele’s rule First day of the last menstrual period Add 7 days Subtract 3 months Add 1 year
Copyright 2008 Allyn & Bacon Prenatal Development Stages of Prenatal Development Germinal 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: Platelike inner part of the blastocyst, which differentiates into the ectoderm, mesoderm, and endoderm of the embryo Trophoblast: Outer part of the blastocyst, from which the amniotic sac, placenta, and umbilical cord develop
Copyright 2008 Allyn & Bacon Prenatal Development Early Days of the Germinal Stage
Copyright 2008 Allyn & Bacon Prenatal Development IF THERE IS A PICTURE OF A ZYGOTE IN THE GERMINAL STATE, PLEASE INSERT IT HERE.
Copyright 2008 Allyn & Bacon Prenatal Development Embryonic 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
Copyright 2008 Allyn & Bacon Prenatal Development Ectoderm Outermost cell layer of the embryo, from which skin and nervous system develop Neural tube: A 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
Copyright 2008 Allyn & Bacon Prenatal Development Amniotic sac The sac containing the embryo and, later, the fetus Amniotic fluid Suspends and protects the fetus Placenta Organ connected to fetus by umbilical cord and serves as relay station between mother and embryo (or fetus), allowing the exchange of nutrients and wastes Secretes hormones that preserve pregnancy, stimulate uterine contractions that induce childbirth, and help prepare breasts for breastfeeding
Copyright 2008 Allyn & Bacon Prenatal Development IF THERE IS A PICTURE OF AN EMBRYO, PLEASE INCLUDE IT HERE. THE FIRST 2 PICTURES OF THE FIGURE ON PAGE 330 WOULD WORK
Copyright 2008 Allyn & Bacon Prenatal Development Fetal stage Begins by the ninth week and continues until birth Fetal movements can be felt Age of viability: The age at which a fetus can sustain independent life During the seventh month, fetus typically turns upside down in the uterus Cephalic presentation Emergence of the baby head first from the womb If not, the fetus, if born prematurely, may be in a breech presentation Emergence of the baby feet first from the womb
Copyright 2008 Allyn & Bacon Prenatal Development IF THERE IS A PICTURE OF A FETUS, PLEASE INSERT IT HERE. THE THIRD PICTURE ON PAGE 330 WOULD WORK.
Copyright 2008 Allyn & Bacon Prenatal Development Environmental Influences on Prenatal Development Mother’s diet Malnutrition Obesity Maternal diseases and disorders 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
Copyright 2008 Allyn & Bacon Prenatal Development Critical Periods
Copyright 2008 Allyn & Bacon 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
Copyright 2008 Allyn & Bacon Prenatal Development 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
Copyright 2008 Allyn & Bacon Prenatal Development Rh 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
Copyright 2008 Allyn & Bacon Prenatal Development Vitamins (high doses) Narcotics Tranquilizers and sedatives Marijuana Alcohol Fetal alcohol syndrome (FAS) Cigarette smoking Increases risk of low birthweight, early infant mortality, and intellectual impairments Other agents, for example X-rays
Copyright 2008 Allyn & Bacon Prenatal Development Chromosomal and Genetic Abnormalities Down syndrome Usually caused by an extra chromosome on the 21st pair Obvious physical characteristics Risk increases with maternal age Sickle-cell anemia More common among certain racial and ethnic groups Causes sickle-shaped red blood cells that can form clumps Tay-Sachs disease Fatal neurological disease Sex-linked genetic abnormalities Recessive trait: expressed if paired with other recessive genes More likely to affect sons of female carriers
Copyright 2008 Allyn & Bacon Prenatal Development Averting chromosomal and genetic abnormalities Genetic counseling Amniocentesis, usually performed at four months and chorionic villus sampling, usually performed at 10 weeks Tests detect Down syndrome, sickle-cell anemia, Tay-Sachs disease, spina bifida, muscular dystrophy, Rh incompatibility, and other conditions, as well as identify the sex of the fetus. Ultrasound Parental blood tests Test of fetal DNA
Copyright 2008 Allyn & Bacon Childbirth Lightening Baby’s head drops into the pelvis, usually early in 9 th 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 contractions
Copyright 2008 Allyn & Bacon Childbirth Stages of Childbirth First stage Uterine contractions efface and dilate the cervix 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
Copyright 2008 Allyn & Bacon 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 Third stage Placenta is expelled In the new world Once baby is breathing adequately umbilical cord is cut Childbirth
Copyright 2008 Allyn & Bacon Childbirth 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
Copyright 2008 Allyn & Bacon 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
Copyright 2008 Allyn & Bacon Childbirth Cesarean section Fetus is delivered through a surgical incision in the abdomen May cause urinary tract infections, inflammation of the uterine wall, blood clots, or hemorrhaging Increases rate of pregnancy-related death 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 24% of births is by C-section. Some view this number as too high
Copyright 2008 Allyn & Bacon Childbirth 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-birthweight 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
Copyright 2008 Allyn & Bacon Childbirth Stillbirth Baby is born dead Connected to fetal abnormalities, infection, maternal medical conditions, and pregnancy complications Most cases have no clear cause
Copyright 2008 Allyn & Bacon The Postpartum Period Postpartum: Following Birth Maternal Depression Baby blues Last for about ten days and do not impair functioning Postpartum depression 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 Affects 1 in 5 to 10 women May last for weeks or months
Copyright 2008 Allyn & Bacon The Postpartum Period Breastfeeding Versus 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
Copyright 2008 Allyn & Bacon The Postpartum Period Resumption of Ovulation and Menstruation Lochia Reddish vaginal discharge that may persist for a month after delivery A nonnursing 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.