CHAPTER 19Pregnancy, Birth, and Childhood

LIFE CYCLE

During sexual intercourse, sperm from the man are deposited into the vagina

The sperm swim through the uterus to the fallopian tubes

If the egg is on its way to the uterus, a sperm may fertilize it

This moment of fertilization is called conception

FERTILIZATION

In the first weeks after fertilization, the fertilized egg undergoes many cell divisions and travels to the uterus

The united egg and sperm is called a zygote The original cell divides to make two cells Embryo: the two-cell stage until about nine

weeks after fertilization in the growing structure Blastocyst: after 5 days after fertilization, the

embryo reaches the uterus, where it floats free for a few days. It is now made of 50-100 cells. The structure is no longer a solid mass of cells, but a sphere of cells surrounding a hollow center

IMPLANTATION

The blastocyst forms and then attaches itself to the wall of the uterus called implantation

Amniotic Sac: a fluid filled bag of thin tissue develops around the embryo after implantation. The sac continues to grow in size as the embryo grows

Placenta: The attachment holding the embryo to the wall of the uterus develops

Oxygen and nutrients move from the mother’s blood into tiny blood vessels that lead to the embryo

DEVELOPMENT

Umbilical cord: 25 days after fertilization, a ropelike structure develops between the embryo and placenta

The growing embryo: during the first 2 months major organs start to form (a heart, kidneys, endocrine glands)

By the end of 8 weeks, the embryo is an inch long

The head makes up about 50 percent of the length of the embryo

FETUS

From month 3 until birth the developing human is called a fetus

Month 3-6, the fetus begins to move and kick, a sign that its skeleton and muscles are developing

Months 7-9, continues to grow and develop Body fat accumulates, eyelids open and close End of 9 months, the fetus is ready to be

born

PREGNANCY

Proper Nutrition: Extremely Important A woman needs to consume about 300

calories more a day Folic acid: essential for proper development

of an embryo’s neural tube which later develops into the spinal cord and brain

Exercise: A fit woman will better meet the extra energy demands of carrying the fetus

Avoiding alcohol and other drugs: abstain from all alcohol, tobacco, and any other drugs not presribed

AVOIDING ENVIRONMENTAL HAZARDS

X-rays: radiation from x-rays can harm a developing embryo or fetus

Lead: main source of exposure to lead is from lead based paint present in older homes

Mercury: exposure to this comes from eating contaminated fish

Cat litter: cat feces can contain a parasite that is especially dangerous to a developing fetus

PRENATAL CARE

Prenatal care: medical care during pregnancy Obstetrician: doctor specializing in pregnancy

and childbirth Trimesters: pregnancy is divided into three

periods of time (around 3 months long)

FIRST TRIMESTER

Record medical history and weight Note conditions that could affect the

pregnancy Prescribe prenatal vitamins as needed

SECOND TRIMESTER

Monitor heartbeat of fetus Measure growth of uterus Monitor for complications using ultrasound

and other tools

THIRD TRIMESTER

Check position and size of fetus Check for warning signs of premature, or

early birth Continue to monitor for complications Discuss birth process

MONITORING

Ultrasound: High frequency waves are used in most pregnancies to create an image of the developing fetus

Gender of the baby More than one fetus Chronic villus sampling: around the 8th week

a test that the doctor removes ad tests a small piece of the developing placenta

CONTINUED

14th-16th of pregnacy: Amniocentesis: procedure involves inserting a

needle into a woman’s abdomen and uterus to remove a small amount of amniotic fluid surrounding the fetus

COMPLICATIONS

Eptopic Pregnancy: the blastocyst implants in the fallopian tube instead of the uterus

Miscarriage: the death of an embryo in the first 20 weeks of pregnancy

Preclampsia: toxemia, characterized by high blood pressure and high levels in the urine, fetus is not getting enough oxygen, bed rest

Gestational Diabetes: diabetes in pregnant women, high blood sugar levels

CHILDBIRTH

3 phases: labor, delivery, and delivery of afterbirth

Labor: Pushing the fetus out Last from 2-24 hours Contractions of the muscles of the uterus cause

the cervix to increase in width or dilate Each contraction lasts from 30 to 90 seconds

DELIVERY OF BABY

This stage can last from 30 minutes to 2 hours

Contractions continue of the uterus and the baby is pushed out usually head first through the cervix and then vagina

The doctor will clamp and cut the umbilical cord

The baby’s mouth and nose are suctioned to get out the mucus

Eye drops are used to prevent infection

DELIVERY OF AFTERBIRTH

The third stage involves contrations of the uterus that push out the placenta, afterbirth

This stage typically takes 15-30 minutes

Postpartum Period: during the first six weeks many changes take place

Mother is changing hormone levels signal the breast to produce milk and the uterus to shrink

COMPLICATIONS AT BIRTH

Some complications result in a surgical delivery or premature birth. Low birth weight and the birth of more thank one baby also may cause complications

A still birth occurs when a fetus dies and is expelled from the body after the 20th week of pregnancy

Cesarean section: surgical method of birth Operation takes about one hour

PREMATURE BIRTH

Delivery of a baby before the 37th week of pregnancy is called premature birth

The earlier the birth the more complications Incubator: a chamber designed to protect the

baby until it has developed. Low birthweight: A newborn that weighs less

than 5.5 pounds

MULTIPLE BIRTHS

Identical Twins: develop from a single fertilized egg or zygote, embryo divides into two identical twins

Fraternal Twins: two eggs are released from the ovary and are fertilized by 2 sperm

Triplets or more: has increased dramatically in the last 25 years

CHILDHOOD

Birth-18 months: Learn to smile about one month Cries to help Learns to sit, crawl, stand, and walk Cries Recognizes parents Baby teeth and can chew food

CHILDHOOD

18 months-3 years Learn to talk play alongside others Learns many words Baby fat is lost and the arms and legs get longer Appetite decreases as growth slows down

THREE TO SIX YEARS

Most lose all traces of babyhood Muscle grow, energy is high, and the curious

child is “into everything” Plays with others Has lots of energy

SIX TO TWELVE YEARS

Becomes less self-centered Has many interests and hobbies

Middle and Late Childhood Physical growth, mastering new skills, and

making friends are key areas of development during middle and late childhood

Pre-adolescence or the tween years: late childhood before adolescence