 … and once EVERY month…. › An egg or OVUM is released from the ovaries and takes 2-3 days to travel (by means of cilia) through the oviduct to the uterus

 When the sperm and egg come together (i.e. sperm fertilizes egg)  If you don’t already know this, write it down.

 During the ZYGOTE stage, the mother may not know she is pregnant

 Pregnancy begins at the moment of conception › Two gametes ( a sperm and an egg cell ) combine to give a complete set of chromosomes to new individual -- ZYGOTE  The Zygote begins to divide about 36 hours after conception.  Zygote after 2 divisions

 After 3 days, cell divisions have produced a ball full of cells (called a MORULA) the same size as original zygote.  Continued cell division forms the blastocyst (hollow ball of cells) which embeds in uterine lining around day 7  ova/miracle/program.html ova/miracle/program.html

 The symptoms arrive around time of implantation (day 7). They include: › Missed period › Inability to bear certain foods › Sensitivity to odors › Discomfort or tenderness in breasts › Morning nausea › Possibly cravings for certain foods  These symptoms may or may not be present… every woman and every pregnancy is different

 Nausea (“morning sickness”) usually doesn’t occur after the 4 month mark  Shortness of breath  Heartburn  Strange cravings  Varicose veins  Lower back pain (caused by change of posture)

 Excessive discharge  Quick weight gain  Excessive thirst  Headaches  Hands, face, or feet swelling  Muscle cramps in legs

 Week 3 – 8  All major body systems begin to form  Placenta forms › Pancake-like shape, has a cord that connects it to baby’s navel (umbilical cord)  Size of embryo – ¼ inch to 1 inch long  Pregnancy may still be unknown to mother

 Living in amniotic fluid requires the baby to obtain its oxygen through the umbilical cord and placenta  3 weeks – heart and nervous system begin to form  Week 5 – brain starts to develop, arm and leg buds can be seen  Eyes & lungs begin to develop

Awareness of pregnancy is important early because of the harm that can be caused by alcohol, viral infections, x-rays and drugs.

 External agents such as viruses, drugs, chemicals and radiation that can harm a developing embryo or fetus.  Time when organ system or body part is at highest risk of effects from teratogens is known as ‘sensitive period’.  Effects of teratogens on a body part or organ system are worst during the period when that structure is forming and growing most rapidly.

 The same defect can be caused by different teratogens.  A variety of defects can be caused by a single teratogen.  The longer the exposure or the higher the ‘dose’ of the teratogen, the more likely it is that serious harm will be done.  The long-term effects of a teratogen often depend on the quality of the postnatal environment.

 From week 8 – birth  3 rd month – spontaneous movement  By end of 3 rd month all organs and major systems have developed, use rest of time to mature  Movement can be felt between 4 th & 5 Th month  Full term between 37 – 40 weeks  Most rapid growth occurs from 3 rd & 7 th month (approx 12 inches)

 5 th month – skeleton hardens (cartilage replaced by bone)  A 6-month old fetus can live in an incubator if born at this time  7 th month – movement gets difficult – too big, head down position  8 th & 9 th month – fat is formed rapidly, sensitive to noise, sucks thumb, hiccups, sneezes, yawns. Aquires immunity from mother’s blood  Full term at between 37 and 42 weeks

 The child’s life and health depends on the mother and her activities/lifestyle  Drugs, alcohol, even diet or sleeping pills, antibiotics, tranquilizers, pep pills, laxatives, painkillers can have effects on a developing fetus…

 Change mother’s physiology, affecting environment of uterus  Cross the placenta unchanged and affect fetus in same way as mother, eg slowing down breathing and heart rates(barbiturates)  Narcotics – herion, cocaine, LSD can cause birth defects › Most importantly, baby can be born addicted, suffering painful withdrawal

 All forms of alcohol pass through placenta to fetus.  It stays in the fetal body system longer than the mother, because of baby’s immature liver  Baby may have serious impairment  Mental handicaps, behavioral problems, learning disabilities, and heart defects  FAS (fetal alcohol syndrome) can occur when mothers drink (usually to babies of heavy drinkers)

 Nicotine and CO enter mom’s blood when smoking › Then into baby’s blood  Baby’s heart rate increases too

 Increases risk of: › spontaneous abortion › bleeding during pregnancy › damage to fetal heart › low birth weight › premature birth