Lifespan Development. Tara L. Kuther

Black: 10.0%

      Non-Hispanic American Indian or Alaska Native: 12.5%

      Non-Hispanic Native Hawaiian or other Pacific Islander: 19.2%

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      This graphic shows gestational age in weeks and identifies:

      1. Which congenital anomaliesare present

      2. Which body systems are most sensitive to teratogens

      3. Common sites of action of teratogens

      Gestation is broken down into three developmental periods.

      Weeks 1 to 2: During this period, the zygote divides, implantation occurs, and a bilaminar embryo develops. The fetus is not susceptible to teratogenesis during this time. Death of the embryo and spontaneous abortion are common.

      Weeks 3 through 8: This is the main embryonic period.

      Weeks 9 through 38: This is the fetal period.

      In general, congenital anomalies are most likely to present earlier in pregnancy. During this time, the body systems of a fetus or embryo are less sensitive to teratogens. Times when body systems are most sensitive to teratogens and are thus most likely to develop defects are tied to times when particular body systems are developing.

       Periods when major congenital anomalies begin to present are as follows:

      Neural tube defects and mental retardation: Weeks 3 to 16

      Truncus arteriosus and atrial septal defect: Weeks 3 to 6

      Amella or meromella: Weeks 4 to 5

      Cleft lip: Weeks 5 to 6

      Low-set malformed ears and deafness: Weeks 4 to 9

      Microphthalmia, cataracts, and glaucoma: Weeks 4 to 9

      Enamel hypoplasia and staining: Weeks 6 to 8

      Cleft palate: Weeks 6 to 9

      Masculinization of female genitalia: Weeks 7 to 9

       Periods when the embryo or fetus is highly sensitiveare listed here by body system:

      Central nervous system: Weeks32 to 38

      Heart: late in Week 6 up to Week 9

      Upper and lower limbs: around Week 5 up to Week 9

      Upper lip: around Week 7 up to Week 9

      Ears: middle ofWeek 9 through approximately Week 33

      Eyes: late Week 8 through Week 38

      Teeth: Week 9 through Week 38

      Palate: early Week 9 up to Week 16

      External genitalia: late Week 9 through Week 38

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      Data for each age group are listed here. All values are approximations.

       Women ages 15 to 19:

      1990: 65

      1995: 64

      2000: 50

      2005: 45

      2010: 40

      2015: 30

      2016: 20

       Women ages 20 to 24:

      1990: 120

      1995: 110

      2000: 110

      2005: 100

      2010: 80

      2015: 70

      2016: 74

       Women ages 25 to 29:

      1990: 119

      1995: 109

      2000: 109

      2005: 110

      2010: 105

      2015: 100

      2016: 102

       Women ages 30 to 34:

      1990: 75

      1995: 85

      2000: 95.

      2005: 98

      2010: 100

      2015: 100

      2016: 103

       Women ages 35 to 39:

      1990: 40

      1995: 42

      2000: 45

      2005: 48

      2010: 48

      2015: 50

      2016: 53

       Women ages 40 to 44:

      1990: 5.5

      1995: 6.5

      2000: 8

      2005: 9

      2010: 10

      2015: 10

      2016: 11

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      The risk of Down syndrome in live births is listed for ages 20 to 45. The age is listed first, followed by the corresponding risk, given as a percentage. Data values are approximations.

      20: 0.1

      21:0.1

      22:0.1

      23:0.1

      24:0.1

      25:0.1

      26:0.1

      27:0.15

      28:0.15

      29:0.15

      30: 0.2

      31:0.2

      32:0.25

      33:0.25

      34:0.28

      35: 0.3

      36: 0.4

      37: 0.45

      38: 0.5

      39: 0.6

      40: 0.9

      41: 1.2

      42: 1.5

      43: 2.0

      44: 2.6

      45: 3.5

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      Stage 1: Dilation. The amniotic sac has ruptured, and the fetus’s head is positioned close to the urinary bladder.

      Stage 2: Delivery. The baby’s head is crowning.

      Stage 3: Expulsion of placenta. The baby has completely emerged from the mother’s body. The umbilical cord remains attached to the placenta. The placenta has separated from the uterine wall and is ready to be expelled.

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      For each racial/ethnic group, two numbers are listed, in this order: (1) percentage of newborns who were very low birthweight and (2) percentage who were low birthweight.

      Non-Hispanic White: 1.13, 6.97

      Non-Hispanic Black: 2.94, 13.18

      American Indian/Alaska Native: 1.33, 7.61

      Asian/Pacific Islander: 1.13, 8.21

      Hispanic (total):