Section 3 Pregnancy and Early Development Chapter 18 Section 3 Pregnancy and Early Development

How a Human Life Begins Life begins with the union of an egg from a female and a sperm from a male. Fertilizations can occur because of sexual intercourse.

Pregnancy Test Page 444- Four Early Signs of Pregnancy and Belief vs. Reality HCG-human chorionic gonadotropin (hormone produced by pregnancy) HCG can be detected as early as 1 week after a missed period. Lab test can usually detect HCG as early as 10 days after fertilization occurs.

Pathway of the Fertilized Egg

The Stages of Pregnancy First trimester The first 3 months after conception The embryo is called a fetus (3rd month) Second trimester Months 4 to 6 Third trimester Months 7 to 9

First Trimester A time of growth and change. After implantation, the embryo starts growing rapidly. By the fourth week a development, the heart starts beating, arms and leg buds appear, and the eyes and brain begin to develop.

Second Trimester 4-6 months is a time when the organ systems continue to develop. By the 4th month, the mother can feel the fetus move or kick. The reproductive organs can be recognized as male or female.

Third Trimester The fetus gains most of its weight. A fetus requires a lot of nutrients from the mother. A large percentage of the iron and calcium in the mother’s food will be delivered to the growing fetus.

Function of Placenta and Umbilical Cord To absorb nutrients & oxygen from mother and pass through the cord to the fetus. Placenta receives wastes from the fetus and sends it back to the mother into the bloodstream. Mother and fetus have 2 separate circulatory systems.

Amniotic Sac The amniotic sac is filled with fluid to protect the embryo/fetus. Through the amniotic fluid and in this sac, the fetus “breathes”.

Staying Healthy Before and During Pregnancy Avoid alcohol and other drugs Maintain a nutritious diet Take prenatal vitamins (Folic Acid, Iron) Get regular moderate exercise Have all medical conditions evaluated by a doctor Page 447- Problems During Pregnancy Chart

Stages of Childbirth Dilatation Expulsion Placenta Pages 448-449- Figure 7

Dilation of the Cervix Can last from 3 hours to an entire day Effacement- thinning out of the cervix Dilation- widening of the cervix Beginning contractions are weak & become intense A mother should go to the hospital when contractions are 5 minutes apart, or her “water breaks”

Left: Beginning of labor. Right: End of the first stage of labor. Dilation of the Cervix Left: Beginning of labor. Right: End of the first stage of labor.

Expulsion- Delivery of the Baby Baby drops farther down the birth canal, usually head first (CROWNING) The mother experiences an urge to push the baby out Continued contractions of the uterus deliver baby (few minutes- few hours) Once the baby is out and breathing on it’s own the umbilical cord it cut and tied.

How will the baby fit?? Passageway expands many times it’s normal size Fetus’ bones are made of cartilage Episiotomy (cut perineum)

Normal

Breech

Cesarean

Cesarean

Delivery of the Placenta “Afterbirth” is expelled The uterus contracts tightly to close off the blood vessels that supplied the placenta through the walls of the uterus

Early Child Development The fastest period of growth after birth takes place from birth to age 1. 2 months- can raise head, smile at faces they recognize 4 months- can roll front to back, more regular eating schedule, many babies can sleep through the night 9 months- crawling 1 year- walking/talking 2 years- social independence, toilet training