Pregnancy & Early Development Chapter 18.3

Objectives Describe how a human life begins. Summarize how a baby develops during the three trimesters of pregnancy. Identify the things a couple can do to stay healthy before & during pregnancy. Summarize four problems that can occur during pregnancy. Describe the stages of childbirth. List the changes that occur during early child development.

Key Vocabulary Sexual Intercourse: The reproductive process in which the penis is inserted into the vagina & through which a new human life may begin. Placenta: A blood vessel-rich organ that forms in a mother’s uterus It provides nutrients & oxygen to & removes wastes from a developing human.

Key Vocabulary Fetus: A developing human, from the start of the ninth week of pregnancy until delivery. Embryo: A developing human, from fertilization through the first 8 weeks of development. Prenatal Care: The healthcare provided for a woman during her pregnancy.

How Life Begins Fertilization The sperm travels from the vagina, through cervix, the uterus, & into the fallopian tubes, where fertilization normally happens. It takes one sperm to fertilize an egg! Once a sperm infiltrates the egg, a chemical change prohibits other sperm from entering the egg.

Life starts when the egg & a sperm unites, it becomes a one cell life called a zygote. All of the genetic information needed to produce a human is found in the zygote.

The Fertilized Egg Divides It takes 3 – 5 days for the zygote to travel down the fallopian tube to the uterus. As the zygote moves down the fallopian tube, it divides into two cells, then four cells, until it becomes a ball of numerous cells.

The Embryo Implants In The Uterus After 3 - 5 days, the ball of hundreds of cells attaches itself to the uterine wall. This is called implantation.

The Placenta Supports the Baby Fetus of about eight weeks, enclosed in the amnion. The baby’s growth in the uterus is dependent on the placenta. Drugs & alcohol, pass through the placenta & become very harmful to the mother & the baby.

Early Signs of Pregnancy A missed menstrual period; often feels like a period is about to start Positive urine or blood test for the HCG hormone Tenderness & enlargement of the breasts Darkening of the nipples. Nausea & fatigue.

How A Baby Develops Begins as one cell Develops into a baby made of trillions of cells over 38 - 40 weeks divided into three trimesters

First Trimester (1-3 months) Size: Grows from the size of a pea to about 1” long What’s Happening?: Heart starts beating Umbilical cord, arms, bones, muscles, lungs, legs, eyes, eyelids, nose, & brain begins to develop

Second Trimester (4-6 months) Size: 5 to 6 inches long Weight: about 5 ounces What’s Happening?: Can yawn & stretch Grows hair, fingernails & toenails Hears & recognizes voices Kicks & makes facial expressions.

Third Trimester (7-9 months) Size: about 20 inches Weight: almost 5 pounds What’s Happening?: A layer of fat forms underneath skin Can open eyes Gains most of its weight Completes organ growth & Can grasp & suck thumb

Keeping Healthy Before & During Pregnancy Avoid alcohol, drugs, & exposure to cigarette smoke Eat healthy Take prescribed prenatal vitamins Exercise regularly, if approved by doctor Have regular check-ups by a doctor

Prenatal Care During Pregnancy Procedures: Need regular doctor’s exams Blood tests Discussion of childbirth options Blood pressure, weight, urine, & fetal heartbeat checks

Prenatal Care Ultrasound: Uses sound waves to draw pictures of a baby on a monitoring screen Shows gender, number of babies & development Amniocentesis: Tests the amniotic fluid for genetic problems Shows the gender of the fetus

Problems During Pregnancy Fetal Alcohol Syndrome Miscarriage Ectopic (tubal) Pregnancy Toxemia Gestational Diabetes Premature Birth Rh Incompatibility

Stages Of Childbirth Contractions: Tightening of the uterine muscles help push the baby out of the uterus & through the vagina for delivery of the baby.

First Stage Dilation: The mother’s cervix expands The membrane surrounding the baby ruptures

Second Stage Expulsion: The baby’s head exits from the birth canal (vagina) The shoulders rotate or turn Stage ends when baby is delivered

Third Stage Placental Stage: The placenta & umbilical cord are expelled after the baby is born Mucus is removed from baby’s mouth so it can breathe The umbilical cord is cut

Types of Childbirth Natural Childbirth: Natural delivery through the vagina Cesarean Section: Baby & placenta are lifted out of mother’s body through an incision made in the lower abdomen & the uterus.

2 Months Can raise head & has good neck control Smiles at faces they recognize Spends several hours awake Mostly sleeps

4 Months Rolls Makes “cooing” sounds Smiles Spends more time awake

Early Childhood Development 6 Months Can sit up 9 Months Crawls 1 Year Walks Talks

Between 5 - 6 Years Ready to begin school Toilet-trained Has well-developed speech Ready to be social

6 - 12 Years Intellectual & psychological changes Learn to read & do math Communicates socially

3D Animation of Vaginal Birth

Review Section 18.3

Key Vocabulary Sexual Intercourse: The reproductive process in which the penis is inserted into the vagina & through which a new human life may begin. Fetus: A developing human, from the start of the ninth week of pregnancy until delivery. Embryo: A developing human, from fertilization through the first 8 weeks of development. Placenta: A blood vessel-rich organ that forms in a mother’s uterus It provides nutrients & oxygen to & removes wastes from a developing human. Prenatal Care: The healthcare provided for a woman during her pregnancy.

Fertilization The sperm travels from the vagina, through cervix, the uterus, & into the fallopian tubes, where fertilization normally happens. It takes one sperm to fertilize an egg! Once a sperm infiltrates the egg, a chemical change prohibits other sperm from entering the egg.

How does a human life begin? The egg & a sperm unites, becomes a one cell life called a zygote. The zygote contains all the information needed to produce a human. It takes 3 – 5 days for the zygote to travel down the fallopian tube to the uterus. The zygote divides until it becomes a ball of numerous cells. The zygote attaches itself to the uterine wall, implantation & becomes an embryo.

How does a baby develop during the three trimesters of pregnancy? 1st Trimester – 1-3 Months Size: Grows from the size of a pea to about 1” What’s Happening?: Major organs & limbs begin to form Embryo becomes a fetus after 8 weeks

2nd Trimester & 3rd Trimester Fetus Grows To: Size: 5 to 6 inches long Weight: 1-2 pounds What’s Happening?: Can yawn & stretch Hears & recognizes voices Kicks & makes facial expressions. Size: about 20 inches Weight: 5 - 7 pounds What’s Happening?: Can open eyes Completes organ growth Can grasp & suck thumb or toes

What can a couple do to stay healthy before & during pregnancy? Avoid alcohol, drugs, & exposure to cigarette smoke Eat healthy Take prescribed prenatal vitamins Exercise regularly, if approved by doctor Have regular check-ups by a doctor

Problems During Pregnancy Fetal Alcohol Syndrome Miscarriage Ectopic (tubal) Pregnancy Toxemia Gestational Diabetes Premature Birth Rh Incompatibility

What are the stages of childbirth? Contractions: Uterine muscles tighten to help push the baby out. 1st Stage - Dilation: The mother’s cervix expands The membrane surrounding the baby ruptures

2nd Stage - Expulsion: The baby’s head exits from the birth canal The shoulders rotate or turn Baby is delivered 3rd Stage - Placental Stage: The placenta & umbilical cord are expelled Mucus is removed from baby’s mouth The umbilical cord is cut

What changes that occur during early child development? 4 Months Rolls Makes “cooing” sounds Smiles Spends more time awake 6 Months Can sit up 2 Months Can raise head & has good neck control Smiles at faces they recognize Spends several hours awake

9 Months Crawls 5-6 Years Ready to begin school Toilet-trained Has well-developed speech Ready to be social 1 Year Walks Talks 6 – 12 Years Intellectual & psychological changes Learn to read & do math Communicates socially