Ch 19 Prenatal Development and Birth Conception and

Ch. 19 Prenatal Development and Birth

Conception and Implantation • Fertilization (Conception): Union of male sperm cell and female egg cell. . At this moment, the genetic makeup is complete, including the sex of the baby • Once occurs, then known as zygote. It starts dividing as it travels through fallopian tube. After a few days, it attaches to uterine wall (implantation). • Between 3 -8 weeks, these cluster of cells are known as a embryo. • After 8 th week, the developing cells are called a fetus.

Embryonic Growth • As embryo grows, it continues to divide forming 3 layers that eventually become body systems. – 1 layer: respiratory & digestive – 2 nd layer: muscles, bones, blood vessels, skin – 3 rd layer: nervous system, sense organs, and mouth.

2 important structures outside embryo: • Amniotic Sac: -thin fluid filled membrane that surrounds and protects embryo -insulates embryo from temperature changes Placenta: thick, blood rich tissue that lines uterine walls during pregnancy. • Umbilical Cord: ropelike structure that connects embryo to mother’s placenta. -Nutrients and oxygen pass through (along w/ harmful substances through cord). Blood supplies are kept separate. Also waste products from embryo pass through cord back to mother for normal waste product disposal.

Development: First Trimester • 0 -2 weeks: spinal cord grows faster than body. Brain, ears, and arms begin to form, and heart forms and begins to beat. Picture above: 4 weeks. Just when pregnancy test would show positive. • 3 -8 weeks: 1”: mouth, nostrils, eyelids, hands, fingers, feet and toes. Nervous system responds and cardiovascular system functional. Picture: 8 weeks (about ½”)

First Trimester: 0 -14 weeks • 9 -14 weeks: human profile- sex organs, fingernails/toenails. Can make crying motion (no sound) and may suck thumb. Picture: 12 weeks. Sex organs maybe clear for Doctor to determine gender.

Second Trimester • 15 -20 weeks: eyes can blink, body begins to grow, head growth rate slows, limbs reaching normal proportions, eyebrows and eyelashes develop. Fetus can grasp and kick. About 4” in size and weighing around 3 ounces.

Second Trimester: 15 -28 weeks Picture: 20 weeks. The baby can suck a thumb, yawn, stretch, and make faces. • 21 -28 weeks: hear conversations, regular cycle of waking & sleeping, weight increases rapidly. - About 12” long and about 1 pound. - Quickening: when your baby is moving around - May survive outside the womb after 24 weeks with special medical care.

Ultrasound Use of sound waves to take a moving picture of a fetus in the uterus. Allows you to monitor baby’s growth, determine sex, and listen to heart beat. Especially important before delivery, to make sure baby is in correct position.

Third Trimester: 29 -birth • 29 to 40: fetus able to use all 5 senses and water able to pass through bladder. Brain scans have shown that some fetuses dream. Mother: a yellowish fluid will start leaking from your breasts. That is colostrum, and it happens to get your breasts ready for making milk. These are full immune cells, antibodies, and proteins. Full “term” delivery any time after 40 weeks. • Approximately 266 days after conception, weighing 6 -9 pounds…birth Fat starts to form under baby’s skin to help fill out wrinkles and gaining over half the weight,

Stages of Birth • Head of fetus moves closer to bottom of uterus. • Mother starts having weak, irregular muscular contractions (weeks to months before) • Labor: final stage where uterus contracts and pushes baby out.

Leaving the womb • Stage 1: Dilation. Contractions of uterus cause cervix to dilate. Contractions break the amniotic sac. • Stage 2: Pass through birth canal. Cervix fully dilated and baby is pushed through the birth canal. Doctors clean and suck out mucus plug and baby cries to clear lungs of amniotic fluid. • Stage 3: Afterbirth Placenta still attached to umbilical cord. Contractions cont. until placenta (now called afterbirth) is pushed out. Dad or Dr. cuts the umbilical cord to separate baby from afterbirth.

Ch 19 Lesson 2 Prenatal Care

Prenatal care • Steps to take provide health for mother and her baby • First decision: find the right obstetrician • Second: where you plan on delivering your baby (birthing center, hospital, home with midwife). • Planning of prenatal visits: physical to monitor weight & BP, ultrasounds, etc

Proper Nutrition • Increased amounts of these nutrients: -Calcium: help builds strong bones & teeth, healthy nerves & muscles, and developing heart rhythm. -Protein: helps form muscle and tissues -Iron: red blood cells and oxygen to cells. -Vitamin A: aids in cell and bone growth, and eye development -Vitamin B: forms nervous system -1 more important…next slide

Folate • Folic Acid: spinal fluid and helps close tube that contains CNS (about 17 -30 days after conception). Most neural tube birth defects occur before female is aware. Recommended that women consume at least 400 -600 micrograms daily.

Caffeine /Diets • Caffeine present in coffee, tea, chocolate, cola, etc. can affect fetus. • High intake has been linked to increased risk of birth defects and low birth weight. • Weight Reduction diets during pregnancy can also harm fetus.

Dangerous Substances • Tobacco- estimated 30% of low birth weight babies, premature births or infant deaths accounted for due to pregnant smoker. Also believed to affect growth, mental and behavior development. • Alcohol- Causes fetal alcohol syndrome. Can cause mental retardation, learning disabilities, behavior problems, and physical defects. Alcohol passes

Drugs • Obviously NO illegal Drugs. • Medications or herbal supplements- even OTCs need to be carefully assessed and gotten approval from medical doctor or pharmacist

Environmental Hazards • Lead- linked to miscarriages, low birth weight, mental disabilities, and behavior problem. Be careful of childhood toys. • Smog- air pollution linked to birth defects, premature birth, stillbirth, LBW, and infant death. • Radiation- Xrays can affect fetal growth, and cause mental retardation. • Cat Litter- cat feces may contain parasites that cause toxoplasmosis. Can result in miscarriage, premature birth, and health problems of newborn.

Complications • Miscarriage- spontaneous expulsion of fetus before the 20 th week. • Stillbirth- dead fetus expelled after 20 th week. • Ectopic pregnancy- zygote implants anywhere other than uterus. #1 cause of death of pregnant women in first trimester. • Preeclampsia (toxemia)-prevents placenta from getting enough blood. Symptoms: HBP, swelling, and protein in urine. Treatment: meds and bed rest