What are some early signs of pregnancy?
From Conception to BirthPeriod of the Zygote Period of the EmbryoPeriod of the Fetus
Period of the ZygoteBegins when egg is fertilized in the fallopian tube.
Period of rapid cell divisionEnds 2 weeks later when the zygote is implanted in the wall of the uterus
Period of the Zygote
Period of the EmbryoFrom 3 to 8 weeks after conceptionBody parts are formed during this period
Embryo rests in the amnion filled with amniotic fluid
Umbilical cord joins embryo to placenta
Prenatal Structures
Period of the FetusFrom 9 weeks after conception to birth
Increase in size and systems begin to function
Age of viability: 22 to 28 weeks
First MonthBy the end of the
first month, the embryo is about 1/10 of an inch long. The heart, which is no larger than a poppy seed, has begun beating.
First Month
Two MonthsThe embryo is about
1 inch long and has distinct, slightly webbed fingers. Veins are clearly visible. The heart has divided into right and left chambers.
Two Months
Three MonthsBy now the fetus is 2 1/2
to 3 inches long and is fully formed. He has begun swallowing and kicking. All organs and muscles have formed and are beginning to function.
Four MonthsYour baby is
covered with a layer of thick, downy hair called lanugo. His heartbeat can be heard clearly. This is when you may feel your baby's first kick.
4 months
Five Months A protective coating
called vernix caseosa begins to form on baby's skin. By the end of this month, your baby will be nearly 8 inches long and weigh almost a pound.
Six MonthsEyebrows and
eyelids are visible. Your baby's lungs are filled with amniotic fluid, and he has started breathing motions. If you talk or sing, he can hear you.
6 Months
Seven MonthsBy the end of the
seventh month, your baby weighs about 3 1/2 pounds and is about 12 inches long. His body is well-formed. Fingernails cover his fingertips
Eight MonthsYour baby is gaining
about half a pound per week, and layers of fat are piling on. He has probably turned head-down in preparation for birth. He weighs between 4 and 6 pounds.
Nine MonthsYour baby is a hefty
6 to 9 pounds and measures between 19 and 22 inches. As he becomes more crowded, you may feel him move around less.
Influences on Prenatal DevelopmentGeneral Risk FactorsTeratogens: Diseases, Drugs, and Environmental Hazards
How Teratogens Influence Prenatal Development
Prenatal Diagnosis and Treatment
General Risk FactorsNutrition: adequate amount of food, protein, vitamins, & minerals
Stress: decreases oxygen to fetus and weakens mother’s immune system
Mother’s Age: neither too young, nor too old
Teratogens: Diseases, Drugs, and Environmental Hazards
• Many diseases pass through the placenta directly and attack the fetus
• Potentially dangerous drugs not limited to cocaine but include alcohol and caffeine
• Environmental hazards are treacherous because we’re often unaware of their presence
How Teratogens Influence Prenatal Development
Not universally harmfulHarm particular structures at a particular point in development in particular animals
Effects of Teratogens
Prenatal Diagnosis and Treatment
Diagnosis: ultrasound, amniocentesis, and chorionic villus sampling can detect physical deformities and genetic disorders
Treatment: fetal medicine and genetic engineering are experimental
Prenatal Diagnosis
Amniocentesis Chorionic Villus Sampling
Labor and DeliveryStage 1: starts when the muscles of the uterus contract and ends when the cervix is fully enlarged (about 10 cm)
Stage 2: baby is pushed down the birth canal
Stage 3: placenta is expelled
Three Stages of Labor
Approaches to Childbirth• Childbirth classes
provide information about pregnancy and childbirth
• Childbirth classes teach pain control through deep breathing, imagery, and supportive coaching
• Mothers who attend classes use less medication during labor and feel more positive about labor and birth
Birth Complications• Lack of oxygen (anoxia): Often leads to surgical removal of the fetus (C-section)
• Premature and Small-for-date infants
• Prematurity is less serious than small-for-date
The Newborn• Assessing the
newborn: Apgar to assess newborns’ health; NBAS for a comprehensive assessment of infants
• 4 primary states: alert inactivity, waking activity, crying, sleeping
• Half of newborns’ sleep is REM (deep sleep)
• Putting the baby to sleep on their back may prevent SIDS
Postpartum DepressionHalf of all new moms feel some irritation, resentment, and crying
10-15% feel more severe postpartum depression
Postpartum depression affects warmth and enthusiasm of mothering
Happy Birthday!!!