Ø Development of Parents is also a factor
Ø 50% of all pregnancies are unintended
§ often met with trepidation, anxiety, fear, mixed emotions
§ often disruptive in terms of job, career, stage of relationship
Ø Process is “biologically programmed sequence of events leading to the birth of a baby” [focus on what goes right]
Ø Many don’t make it, however:
§ 50 to 70% of fertilized eggs [one-celled zygotes] die within the first 2 weeks
§ of those that do survive, 25% will miscarry, spontaneously abort, before birth
Ø Periods & Trimesters; terms not used consistently
§ Book: “Trimesters simply break the 9 months of the mother’s pregnancy into three 3-month segments.” Each about 13 weeks.
· Health care pros.: calculate “weeks of pregnancy” from first day of last period; usually about 2 weeks before conception.
§ “periods are more specific than trimesters and reflect developmental mile stones
· Germinal period; Embryonic period; Fetal period
Ø Ova generally mature one at a time, although a woman is born with all of the ova will ever have. Men produce about 1 billion sperm cells every day, depositing approximately 300 million with each ejaculation.
Ø Generally only one will fertilize an ovum. Exception: dizygotic twins or multiples. Estimated that 80% of multiple births from 1996 & 1997 were result of fertility interventions.
Ø A mature ovum can survive for 3 -5 days. Sperm can live 2 -3 days in the vagina. This provides a period of about a week that conception can occur.
Ø Germinal Period: fertilization to implantation - about 2 wks.
§ Zygote splits 3X, one cell becomes 8; forms a “blastula” in about a week
§ Blastula – fluid-filled sphere of undifferentiated cells
§ Differentiation – cells separate according to function: those that will become new human & those that develop into support structures [placenta, etc.]
§ Support structures support secrete hormone [hcg, human chorionic gonadotopin] which shuts down ovulation & menstrual periods]
§ Implantation – blastula burrows into uterus wall
Ø Embryonic Period – lasts about 6 weeks. Begins when implantation is complete
§ Two simultaneous process occur:
(1) Outer layer of cells begin producing all the tissue for support structures [amniotic fluid & sac, umbilical cord, placenta]
(2) Inner cells become embryo itself
§ Embryo develops legs, arms, fingers, toes, face, a beating heart, brain lungs & all other major organs.
§ By end of this period embryo is recognizably human
§ By end of 2nd trimester embryo/fetus reaches “the age of viability” & has a 50/50 chance of survival outside the womb
Ø Fetal Period – lasts from start of 3rd month to birth – about 7 months
Ø Summary
o 1st trimester – Basic structures are beginning to be formed
o 2nd trimester – organs mature, especially the brain
o 3rd trimester – major maturation of brain & “rehersal” or “trial run” of organs & systems
Ø Developmental Trends or Growth Patterns
o Cephalocudal [SI-FOE-LO-CODL] – head down; top to bottom
o Proximodistal [PROX-A-MO-DIS-TAL] – near to far; middle of body out
o Gross to specific - with generalized, whole body movements at first, with these responses becoming more local and specific later
Prenatal Environmental influences
Ø Maternal age
o Older mothers are at greater risk for miscarriage
o Teenage mothers have increased risk since their bodies may not be able to sustain a healthy developing child
o Older women have older ova that could be defective
Ø Maternal health & nutrition
o Malnutrition during pregnancy can cause babies with low birth weight, smaller head size, and smaller overall size
o Reduced brain development can occur
o Temporary malnutrition usually has no long lasting effects
Ø Prenatal health care
o 5 or more visits to a doctor is one of the best predictors of delivering healthy babies
o Health care has been shown to be effective in reducing infant mortality and premature birth rates
Ø Critical periods the period of development during which the effect of a teratogen occurs
Ø TERATOGEN – toxic agent of any kind that potentially causes abnormalities in the developing child
o Teratogens and their effects
§ Maternal diseases
· Among the most devastating teratogens
· Diseases that are contracted by the mother and are passed along to the developing embryo or fetus
· Because the placenta keeps the mother’s and baby’s blood supplies separate, it can screen some larger disease molecules and keep them from being passed from mother to baby
· HIV is transmitted by infected mothers about 25% of the time; if treated this can be reduced to 5%
§ Prescription and over the counter drugs
· Sometimes a drug can be harmless to the mother but dangerous to the baby
· The drug may arrest or interfere with developing organ systems, but not have an affect after development is complete
§ Alcohol
· FETAL ALCOHOL SYNDROME – a set of congenital abnormalities, including small size, low birth weight, certain facial characteristics, and possible mental retardation that result from maternal alcohol consumption during pregnancy
· FETAL ALCOHOL EFFECTS – similar to FAS, although with milder abnormalities; due to drinking alcohol during pregnancy
§ Tobacco
· Spontaneous abortion, still birth, and premature birth are significantly more likely if the mother smokes
· Damage to the placenta caused by smoking interferes with nutrient transmission
· ANOXIA – lack of oxygen; can cause brain damage
§ Marijuana
· May affect central nervous system
· May later damage the neurological and cognitive control
§ Cocaine and other amphetamine drugs
· Infants have a higher risk of prematurity, growth retardation, mental retardation, and neuromotor dysfunction
· Discontinuing cocaine use can limit the damage
Childbirth Stages
Ø initial labor - the first stage of labor, during which the cervical opening of the uterus begins to dilate to allow for passage of the baby [cervix: 0-3 cm. dilation]
o false labor/Braxton-Hicks contractions; generally diminish if the mother walks
o Average initial labor for first born is 12 -15 hours; 6 – 8 for subsequent children; Can be anywhere from 15 minutes - 30 hours
o contractions 15 -20 min. progressing to 3 - 5 min
o release of mucus plug sealing the cervix; “bloody show” or “showing”
o “water breaks” – amniotic sac ruptures & fluid is released [gushes]
Ø 2nd stage [again: terms used inconsistently] Active Phase [cervix: 4 - 7 cm.]
o stronger, longer, more regular contractions – every 2 to 3 minutes
Ø Transition stage- briefest stage [cervix: 8 -10 cm. dilation]
o Longer and more intense contractions; Contractions last 1 to 2 minutes with only ½ to 1½ minutes “rest”
o Very intense
o Lasts 10 to 60 minutes
o The head emerges from the birth canal
o EPISIOTOMY – an incision to enlarge the vaginal opening: done less often in Europe than U.S.
Ø AFTERBIRTH – the third and last stage of childbirth, typically occurs within 20 minutes after delivery during which the placenta and the umbilical cord are expelled from the uterus
o Approaches to childbirth
§ The changing views of childbirth
· MIDWIFE – a woman who is experienced in childbirth, with or without training, who assists with home delivery
· TRADITIONAL CHILDBIRTH – hospital labor and delivery
§ Contemporary childbirth practices
· NATURAL OR PREPARED CHILDBIRTH – childbirth based on procedures developed by Fernand Lamaze, a French obstetrician
· BIRTHING CENTER – place designed to accommodate the entire birth process, from labor through delivery and recovery
o Advances in technology
§ Prenatal screening
· ULTRASOUND – a technique that uses sound waves to produce a picture of the fetus in the uterus
· AMNIOCENTESIS – the withdrawal and analysis of amniotic fluid with a syringe to obtain discarded fetal cells for testing
· CHORIONOIC VILLUS SAMPLING – the withdrawal and analysis of cells from the membranes that surround the fetus, either with a syringe or with a catheter. Because more cells are collected in this procedure than in amniocentesis, the test can be completed more quickly
§ High technology for high risk pregnancies
· FETAL MONITOR – the external monitor records the intensity of uterine contractions and the baby’s heartbeat by means of two belts placed around the mother’s abdomen. The internal monitor consists of a plastic tube containing electrodes that is inserted through the vagina and attached to the baby’s head
· External monitors record the intensity of uterine contractions and the baby’s heartbeat by means of two belts placed around the mother’s abdomen
· Internal monitoring is more invasive that records directly by placing tubes containing electrodes into the vagina and on the baby’s head
o Complications in childbirth
§ BREECH PRESENTATION – the baby’s position in the uterus where the head will emerge last; assistance is sometimes needed in such cases to prevent injury to the infant, including anoxia
§ CESAREAN SECTION – surgical procedure used to remove the baby and the placenta from the uterus by cutting through the abdominal wall
§ APGAR SCORING SYSTEM – a standard scoring system that allows physicians to evaluate an infant’s condition quickly and objectively
§ Premature birth
· PRETERM STATUS – an infant born before a gestation period of 35 weeks
· SMALL FOR DATE – a full term newborn who weighs less than five pounds, eight ounces
Ø The evolving family
o The transition to parenthood
§ Adjustments for the mother
· May feel nauseated, experience fullness or tingling in her breasts
· May be fatigued and emotionally hypersenstive
· Physical discomfort and emotional burden
· Uncertainty about the future
· Wonder whether or not they will be able to fulfill the expectations of everyone who will need them
§ The fathers changing role
· Some may feel left out while others feel excited and prideful
· Expectant father may also go though some of the symptoms of their wife’s pregnancy
o The arrival of the neonate
§ NEONATE – baby in the first month of life
§ The trauma of being born
· Normal full term babies are well prepared to cope with the stressful time
· First breaths may be difficult because of amniotic fluid in the lungs
§ Size and appearance
· FONTANELS – the soft bony plates of skull connected by cartilage
· External genitalia may appear enlarged due to presence of hormones
· Vernix caseosa may be present
· Weighs between 5 pounds 8 ounces and 9 pounds 8 ounces
· Between 19 and 22 inches long
§ The first few days: a period of adjustment
· Significant adjustments in respiration, blood circulation, digestion, and temperature regulation
· Digestion changes radically
· Breathing can cause coughing and sneezing to clear the mucus and amniotic fluid from the lungs
· Reflexes
o SURVIVAL REFLEXES – biologically programmed behaviors, such as breathing, rooting, and sucking, that are related to the neonate’s ability to survive
o PRIMITIVE REFLEXES – biologically programmed behaviors without immediate survival value, but which may have been associated with survival in our evolutionary past
§ The beginning of attachment
· ATTACHMENT – the reciprocal emotional bond that develops between a child and caregivers
· Attachment is reciprocal
· Establishes the foundation for later social and personality development
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