Prenatal Development

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Prenatal Development

• What are some early signs of pregnancy?

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From Conception to Birth

• Period of the Zygote
• Period of the Embryo
• Period of the Fetus

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Period of the Zygote

• Begins when egg is fertilized in the fallopian
  tube.
• Period of rapid cell division
• Ends 2 weeks later when the zygote is implanted
  in the wall of the uterus

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Period of the Zygote
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Period of the Embryo

• From 3 to 8 weeks after conception
• Body parts are formed during this period
• Embryo rests in the amnion filled with amniotic
  fluid
• Umbilical cord joins embryo to placenta

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Prenatal Structures
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Period of the Fetus

• From 9 weeks after conception to birth
• Increase in size and systems begin to function
• Age of viability 22 to 28 weeks

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First Month

• By 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.

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First Month
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Two Months

• The 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.

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Two Months
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Three Months

• By 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.

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Four Months

• Your 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.

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4 months
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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.

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Six Months

• Eyebrows 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.

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6 Months
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Seven Months

• By 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

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7 Months
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Eight Months

• Your 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.

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8 months
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Nine Months

• Your 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.

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Influences on Prenatal Development

• General Risk Factors
• Teratogens Diseases, Drugs, and Environmental
  Hazards
• How Teratogens Influence Prenatal Development
• Prenatal Diagnosis and Treatment

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General Risk Factors

• Nutrition adequate amount of food, protein,
  vitamins, minerals
• Stress decreases oxygen to fetus and weakens
  mothers immune system
• Mothers Age neither too young, nor too old

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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
  were often unaware of their presence

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How Teratogens Influence Prenatal Development

• Not universally harmful
• Harm particular structures at a particular point
  in development in particular animals

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Effects of Teratogens
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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

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Prenatal Diagnosis
Amniocentesis
Chorionic Villus Sampling
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Labor and Delivery

• Stage 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

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Three Stages of Labor
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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

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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

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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

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Postpartum Depression

• Half 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

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Happy Birthday!!!