CHAPTER 19PRENATAL DEVELOPMENT AND

BIRTH

LESSON 1- THE BEGINNING OF THE LIFE CYCLE

In this Chapter we will discuss events from fertilization to birth

Describe Prenatal care

Indentify Prenatal risks

PRENATAL DEVELOPMENT We begin life from a single cell

During the 9-month period, the cell will divide millions of times

It will form tissues, organs, body systems, & characteristics of the person it will become

CONCEPTION AND IMPLANTATION Fertilization: Union of egg cell(female) and the sperm cell (male) Also known as conception

Zygote: Fertilized egg cell Takes about 4 days to reach the uterus Once formed, a protective membrane surrounds it to

prevent more sperm from entering the ovum Divides many times (mitosis-cell division) to form a

cluster of cells with a hollow space in the middle After 5 days, the zygote reaches the uterus & is called

Blastocyst

Implantation: the zygote attaches to the uterine wall Takes about 10 days to implant The endometrium tissue protects & nourish the egg

A CLOSER LOOK!

EMBRYONIC GROWTH Embryo: A cluster of cells following implantation Called an embryo for about 8 weeks

3 layers of tissue formed as cell continues dividing:

Respiratory & digestive system Muscles, bones, blood vessels, & skin Nervous system, sense organs, mouth

EMBRYONIC STAGES

EMBRYONIC GROWTH

Amniotic Sac: Thin membrane formed to surround the developing embryo

Amniotic Fluid: Fluid in the amniotic sac Acts as a shock absorber Insulates from temperature changes Allows fetal movement Permits proper lung development Constantly circulated by the baby swallowing

& inhaling existing fluid & replacing it through exhalation & urination.

EMBRYONIC GROWTH

Placenta: Provides nutrition, excretion, & immunity Blood rich tissue made by embryonic cells &

the tissue from the mother

Umbilical Cord: Tube which nutrients & oxygen pass from the

mother’s blood to the embryo Carries waste products from embryo to

diffuse into the mother’s blood

FETAL DEVELOPMENT

Conception to birth is usually about 9 months Divided into (3) 3-month periods called

Trimesters

First Trimester: 0-14 weeks

Second Trimester: 15-28 weeks

Third Trimester: 29 weeks to birth

Let’s look at pages 488-489 to see what’s going on in these stages of fetal development!

STAGES OF BIRTH

The last few weeks of pregnancy, the baby’s head moves to the lower part of the uterus

95% of the time it rests on the cervix

Dilation: Cervix stretches because of mild contractions (Labor) Contractions break the amniotic sac (water breaks) Cervix dilated about 3 cm Contractions are about 5-20 minutes apart

STAGES OF BIRTH Birth: Contractions are 1-3 minutes apart (active labor) Cervix 8 to 10 cm Stage lasts minutes to hours Baby passes through the birth canal Cries to clear lungs and amniotic fluid Umbilical cord cut

Apgar Test: Routine diagnostic test to determine the physical condition of the baby

Appearance Reflex Activity Pulse and respiration

AFTERBIRTHCONTRACTIONS CONTINUE TO PUSH OUT THE PLACENTA

15-30 MINUTES LATER

Umbilical Cord Placenta

HOW ARE TWINS BORN?

Single egg fertilized by single sperm that divides to form 2 embryos

Same genetic info

Same gender

Ovaries release 2 eggs

Separate sperm fertilize each egg

Different genetic makeup

May or may not be the same gender

Identical Fraternal

1 OUT OF 87 BIRTHS RESULT IN TWINS (1/3 BEING IDENTICAL)1 OUT OF 7570 ARE TRIPLETS1 OUT OF 658,00 ARE QUADRUPLETS1 OUT OF 57, 290, 000 ARE QUINTUPLETS1 IN 50,000 ARE BORN CONJOINED

PAIN RELIEF DURING PREGNANCY

Anesthetic: Local-numbs the vagina Regional-eases the pain of contractions Spinal: Injection into the spine (works immediately) Epidural: Tube inserted into the back for medicine to be released

throughout labor General: Puts patient to sleep (used mainly in C-sections)

Birthing Tube: Warm soak Promotes deep relaxation Reduces anxiety Relieves pain

Lamaze: Used since the 1950’s Started mainly with breathing exercises Goal is to increase the mother’s confidence in their ability to give

birth

COMPLICATIONS DURING PREGNANCY

Miscarriage: Spontaneous expulsion of the fetus before the 20th week

Still Birth: Death of a fetus after week 20 of pregnancy

Ectopic Pregnancy: Zygote implants in the fallopian tube, abdomen, ovary, or

cervix Egg cannot get to the uterus because of inflammation or

scar tissue resulting from a STD Stone baby

Preclampsia: Toxemia prevents the placenta from getting enough blood

High Blood pressure and high protein in the urine Bed rest, meds, or hospitilization

PROBLEMS WITH PREGNANCIES

Ectopic pregnancy Breech position