Pregnancy and Birth

The Beginning of the life cycle

Fertilization / Conception When the males sperm enters the females egg 1 sperm / 1 egg Within seconds of fertilization, the surface of the egg changes so that no more sperm may enter the egg

Zygote The united egg and sperm Within 36 hours, while the zygote is in the fallopian tube, it begins to divide

Cell Division The original cell divides to make 2 cells 2  4 4  8 8  16, etc. From the 2 cell stage until about 9 weeks after fertilization, the growing structure is called an embryo

The Blastocyst 5 days after fertilization, the embryo reaches the uterus Floats free 50 to 100 cells Blastocyst – sphere of cells surrounding a hollow center

Implantation Once the blastocyst forms, it implants itself in the uterus  implantation

Development in the Uterus

Amniotic Sac After implantation, a fluid-filled bag of thin tissue called the amniotic sac develops around the embryo It grows as the embryo grows Embryo floats in amniotic fluid

Placenta The attachment that holds the embryo to the wall of the uterus Here, oxygen and nutrients move from the mothers blood into the embryo Dangerous substances can pass from mother to embryo, too Alcohol, drugs, chemicals

Umbilical Cord 25 days Ropelike structure Connects embryo to placenta The embryo’s lifeline Carry nutrients and oxygen from the placenta to the embryo Carry wastes from the embryo to the placenta

The Growing Embryo During the first 2 months: At the end of 2 months: Major body systems and organs form Heart, Blood vessels, Kidneys, Endocrine glands At the end of 2 months: Embryo is an inch long Recognizable external features Eyes, ears, arms, legs Head makes up 50% of embryo

The Fetus From the 3rd month until birth, the developing human is called a fetus 3rd to 6th months – begins to kick Skeleton and muscles are developing Nervous system matures Sense organs begin functioning Fetus becomes sensitive to light and sound Alternates periods of activity with sleep

The Fetus 7th to 9th months End of 9th month Body size increases; more proportionate Body fat accumulates Eyelids open and close End of 9th month Fetus is ready to be born

Worksheet Word Bank Fertilization Embryo Blastocyst Fertilization Early Cell Division Blastocyst & Implantation Late Cell Division Cervix Vagina Amniotic Sac Developing Placenta Amniotic Fluid Uterine Wall Umbilical Cord

A healthy pregnancy

Staying Healthy During Pregnancy Proper nutrition “eating for two” Exercise Better meet the energy needs of carrying a baby Avoiding alcohol and other drugs Harm, kill, decrease chance to live, lifelong problems Avoiding environmental hazards X-rays, lead, mercury (fish), cat litter (parasites)

Prenatal Care Medical care during pregnancy Obstetrician – doctor specialized in pregnancy and childbirth The chances of having a healthy baby greatly increases with regular doctor checkups throughout pregnancy

3 Trimesters Pregnancy is divided into 3 periods of time Each is about 3 months long 1st trimester  0-3 months 2nd trimester  3-6 months 3rd trimester  6-9 months

Monitoring Tools Ultrasound Chorionic Villus Sampling (CVS) High-frequency sound waves that produce an image of the fetus Chorionic Villus Sampling (CVS) At 8 weeks, dr. removes part of the placenta to check for abnormalities/disease Amniocentesis 14-16 weeks, inserting a needle in the abdomen and uterus to remove amniotic fluid to test for abnormalities

Complications Ectopic pregnancy Miscarriage Preeclampsia Blastocyst implants in the fallopian tube, not the uterus Miscarriage Death of embryo or fetus in first 20 weeks Preeclampsia High BP, swelling of wrists & ankles, high levels of protein in urine  prevents fetus from getting O2 Gestational diabetes Developing diabetes while pregnant

childbirth

The Birth Process Labor Delivery of the baby Delivery of the afterbirth

Labor Work performed by the mother’s body to push the fetus out 2 to 24 hours or longer Uterus contracts, causing the cervix to increase in width, or dilate Amniotic sac will break Cervix becomes softer and wider too allow the fetus to pass through

Delivery of Baby Actual birth, or delivery of baby Lasts 30 minutes to more than 2 hours Baby usually exits head first through vagina Once the baby is out: Dr. clamps and cuts the umbilical cord Baby’s nose & mouth are suctioned to remove mucus and make it easier to breath Eye drops are given to prevent infection Injection of vitamin K to prevent excess bleeding from umbilical cord

Delivery of Afterbirth Though the baby is born, the birth process is not complete Uterus contractions push out the placenta 15 to 30 minutes

Complications at Birth Surgical delivery Premature birth Low birth weight Birth of more than one baby

Surgical Delivery Sometimes delivery through the cervix and vagina is not possible due to the position of the fetus or the narrowness of the mothers hips Illness or other conditions that make vaginal delivery dangerous for mother and/or baby

Cesarean Section Surgical method of birth Doctor makes an incision in the lower abdomen into the uterus Then removes the fetus and placenta

Premature Birth Baby is born before it is fully developed Before the 37th week of pregnancy Earlier birth  more problems Lungs are usually not developed Receive care in an incubator

Low Birth Weight Less than 5.5 pounds May also be premature May be full-term, just didn’t grow enough before birth Increased risk of health problems as a newborn, chronic lifelong problems, death

Multiple Births The delivery of more than one baby Twins Triplets Quadruplets Carry greater risk to mother and babies

Identical Twins Develop from single fertilized egg Embryo divides into 2 identical embryos Because they divide from identical embryos, they have the same inherited traits and are the same sex

Fraternal Twins Sometimes 2 eggs are released from the ovary and fertilized by 2 sperm Fraternal twins are no more alike than any other siblings May or may not be the same sex

Triplets or More Less common than twins Number of cases has dramatically increased in the last 25 years