Warm up 8/31 List everything that you know about pregnancy and in-utero development.List everything that you know about pregnancy and in-utero development.

Prenatal Development & Complications

Fertilization Midway through menstrual cycle – ovulation occurs When sperm penetrates egg all other sperm are repelled. Unified cell called a zygote.

First Trimester Zygote (fertilization to three weeks) Embryo (fourth through eight weeks) Fetus (ninth week through birth) –First trimester ends during the third month –Second trimester ends during the sixth month The zygote at two different stages of development

The Germinal Period: First 21 Days Division of zygote begins within 36 hours of fertilization Implantation in uterus happens about six days after fertilization

The Germinal Period: First 21 Days During the third week of the germinal period, the zygote forms the embryonic disc –the ectoderm (skin and nervous system) –the mesoderm (muscles, bones, and the circulatory, excretory, and reproductive systems) –The endoderm (digestive system and lungs) –neural tube develops (central nervous system)

The Embryo: Weeks Four - Eight Fourth week: head and blood vessels begin to develop and heart begins to beat End of the first month: eyes, ears, nose, and mouth start to form; buds that will become arms and legs appear –1/5 th inch long Second month: upper arms, forearms, hands, and fingers appear, followed by legs, feet, and toes; fingers and toes separate (no longer webbed)

The Embryo: Weeks Four - Eight End of the second month: head is more rounded, features of the face fully formed; has all basic organs except sex organs; buds for first baby teeth –1/30 th ounce and 1 inch long All sex organs are the same until the X or Y chromosome calls for testes or ovaries

The Fetus: Weeks Nine - Birth Third month: muscles develop, cartilage replaced by bone; all major organs complete their formation, including stomach, heart, lungs, and kidneys; sex organs take discernable shape End of the third month: can move almost every part of body (kicking legs, sucking thumb, squinting, and frowning); has fully formed fingerprints –3 ounces and 3 inches

Trimester Two Time for essential organ and brain maturation Hair, including eyebrows and eyelashes, begins to grow Fingernails, toenails, and buds for adult teeth form Fetus at 23 weeks

Trimester Two Fifth month: mother can feel the baby move The brain increases sixfold in size 22 weeks: 22 ounces 26 weeks: 2 pounds

Trimester Three Time for final prenatal maturation Lungs begin to expand and contract so infant can breath outside the womb Valves of the heart go through final maturation Brain development is also ongoing; at 34 weeks, distinct sleeping and waking patterns can be measured Substantial weight gain (from approx. two pounds to approx. 7.5 pounds)

Complications Diseases –Rubella –HIV –Syphilis –Genital herpes Drugs –Alcohol –Tobacco –Heroin/Methadone –Cocaine/Marijuana

Complications – Diseases Rubella –Also called German measles –Contracted early in pregnancy, may cause blindness, deafness, heart abnormalities, and brain damage HIV –When a woman who carries the HIV virus becomes pregnant, there is a 15 – 30% chance that her fetus will become HIV-positive –50% of HIV-positive infants die by age three

Complications – Diseases Syphilis –Can be cured with penicillin –Disease-causing organisms cannot cross placenta during first three months of pregnancy, so it’s important for early treatment –If not treated, fetus may die or suffer bone or brain damage Genital herpes –Can cause infant death, blindness, and mental retardation

Complications – Drugs Alcohol –Fetal Alcohol Syndrome (FAS) Estimated 3 out of 1,000 babies are born with FAS –Distinctive symptoms: growth retardation; brain damage; facial abnormalities (small heads, abnormally spaced eyes, flattened noses, low-set, unparallel ears; abnormalities of the skeleton and joints

Complications – Drugs Tobacco –Every puff of a tobacco product reduces the amount of oxygen to the fetus and increases the toxins, impeding nutrition –Smoking during pregnancy increases the possibility of lowered birth weight and shorter length –Other possible complications: spontaneous abortion, death in uterus, premature separation of the placenta from the uterus, greater need for intensive care, possibly asthma, cleft lip and palate and lower scores on cognitive tests

Complications – Drugs Heroin/Methadone –Babies born to addicted mothers are born addicted as well –Can possibly die of withdrawal symptoms if not treated at birth –Addicted babies more likely to suffer from learning disabilities –Other complications: low birth weight, jaundice, breathing difficulties,

Complications – Drugs Cocaine/Marijuana –Possible complications include premature labor and more time spent in intensive care, restricted blood flow to the placenta, resulting in poorer prenatal brain development, and babies who are quick to start and slow to adjust to the sights and sounds around them –Cocaine users are more likely to have premature babies with low birth weights and attention problems –Heavy marijuana use can lead to sleep disturbances and premature birth