PREGNANCY and CHILDBIRTH

The Developing Baby (section1) Conception Sperm penetrate and fertilizes the ovum Pregnancy begins Called Conception

All about the Woman Ovum Approximately every 28 days an ovum (egg) is released by one of woman’s two ovaries Ovulation – this occurs as part of the woman’s menstrual cycle Hormones are released and woman’s body prepare the uterus in case ovum becomes fertilized If fertilization does not occur, the lining that was formed in the uterus is shed as the monthly menstrual period

Uterus – The organ in the woman’s body in which new baby develops during pregnancy It is pear shaped – about the size of your fist Strongest muscle and is able to expand during pregnancy

When ovum released…travels through the Fallopian Tube…this connects the ovary to the uterus This journey takes 2 - 3 days When ovum reaches the uterus it USUALLY disintegrates and leaves the body with the menstrual flow

If a sperm (male cell) reaches the Fallopian tube and penetrates the ovum…conception occurs Ovum live about 12 – 24 hours

Sperm is capable of fertilizing an ovum about 48 – 72 hours During a woman’s menstrual cycle…about three– four days that intercourse can lead to conception If conception occurs as the baby is developing this is called PRENATAL DEVELOPMENT

Stages of Pregnancy First Stage Formation of Zygote (fertilized egg) Germinal Stage First Stage Formation of Zygote (fertilized egg) Germinal Stage lasts about two weeks Key Steps of Pregnancy Occur Cell Division Zygote grows by cell division while still in the fallopian tube Rapid growth for about four days Reaches the uterus Implantation Lining of uterus is thick enough for the zygote to attach itself and continue to grow Zygote implants in the uterus Size of the head of a pin

Stages of Pregnancy Embryonic Stage Baby is now called an embryo Third week through about the eighth week of pregnancy Rapid growth Organs and body systems Cells divide into major systems: heart lungs bones Muscles Systems continue to grow and are too immature to function on their own

Neural tube – tube in the back of the developing baby – will become the brain and the spinal cord (Folic Acid in daily diet) About 27 days after conception the neural tube closes and the brain begins to take control of the body systems By sixth week, connections between brain and spine allow movements of embryo (mom cannot feel movements and she might not even know she is pregnant!)

At this time, brain is sensitive to damage from any drugs or alcohol mom might take If any woman is engaging in activities in which she might conceive…it is imperative that she avoid all alcohol and drugs

A sac firms around the embryo…this is the amniotic sac It is filled with amniotic fluid that cushions and protects the developing baby The sac is formed from layers of cells in the uterus The developing embryo is about 1 inch long

Placenta develops…tissue from special layers of cells in uterus Rich in blood vessels and is attached to the walls of the uterus Mom’s bloodstream carries food and oxygen to the placenta Placenta absorbs oxygen and nourishment from mom’s blood and transports to the baby through the umbilical cord

Umbilical cord connects the baby to the placenta Umbilical cord takes carbon dioxide and other waste products away from the baby and to the placenta Umbilical cord is rarely flexible enough to loop around the baby’s neck Umbilical cord and placenta provide everything the baby needs until birth

Fetal Stage Longest stage begins about 8th or 9th week continues till baby’s birth Developing baby is now called a “fetus” Buds for 20 “baby teeth” appear Vocal cords develop Digestive system and kidneys begin to function By end of third month spontaneous movements are possible

Development continues as fetus prepares to live independently During fourth or fifth month fetus can touch the walls of the uterus when stretching or kicking…mom can now feel these (Quickening) Development continues as fetus prepares to live independently Major organs become ready to function without mom’s help Fat deposits accumulate under the skin Fetus’ appearance becomes smoother and rounder Fetus store nutrients and builds immunity to diseases and infections By seventh baby is developed enough that it could live outside of the womb but needing a lot of medical help

Fetus continues to grow Fetus can: Suck its thumb Cough Sneeze Yawn Hiccup Fetus continues to grow Amount of amniotic fluid increases as fetus grows Uterus expands During last few months of pregnancy fetus doesn’t have a lot of room to stretch and takes on “fetal position” Note page 108 and 109 in text book…fetal development month by month

Preparing for Birth Length of pregnancy… 40 weeks 280 days from last menstrual cycle Toward end of 40 weeks baby’s weight shifts downward called “Lightening” Baby’s head drops into birth canal Most babies are born with head down If seat down or feet down this is called Breech Presentation Sometimes requires a Caesarian Birth Even though mom’s uterus and abdomen have stretched to limits…they return to normal size and shape about six weeks after delivery

Closer Look at Conception Heredity Passing on of characteristics Inherited characteristics Physical characteristics Predisposition of talents or abilities Medical conditions

Chromosomes Genes Genome DNA Tiny threadlike structures in nucleus of cell At conception every human baby receives 46 chromosome 23 chromosomes from mom 23 chromosomes from dad Genes Genes determine a human’s inherited characteristics Each chromosome has thousands of genes Genome Blueprint for each person DNA Genes are made up of DNA Human’s 46 chromosomes make up that persons DNA No one has identical DNA except identical twins

This gene is not expressed in the inherited characteristic Each person receives two genes for every inherited characteristic one from mom and one from dad If the genes are the same, that person inherits that characteristic If the genes are different the characteristic is controlled by the stronger gene Dominant Genes The stronger gene Recessive Genes The weaker gene This gene is not expressed in the inherited characteristic

Heredity tells us how people in a family resemble each other Heredity also explains why people in a family look quite different Each sperm and egg contain a different combination of genes Sex of a child is determined at conception Sex chromosomes come in two types X and Y Each ovum in woman’s ovaries carries an X chromosome Each sperm in the man’s body carries either an X or a Y chromosome XX combination is a girl XY combination is a boy

Multiple Births Identical Twins Multiple Births – Birth to more than one child at a time Twins the most common multiple birth Identical Twins Woman’s ovum is fertilized Cell division occurs Mass of cells split in half and two separate masses are present Each mass of cells continues to divide and grow into separate embryos One ovum One sperm Two babies Same sex Same DNA Very similar physical characteristics

May be the same sex or one of each Fraternal Twins Two eggs are released at the same time Each fertilized by two different sperm Fraternal twins are siblings who happen to be in mom’s womb at the same time May be the same sex or one of each 3% of all births are twins (3 out of 100 births) 23 out of 1000 births are fraternal twins Out of this 1000 births only about 4 will be identical twins Birth of 3 or more babies is rare Rise in use of fertility treatments increases chance of greater number of babies

Family Planning Every time a couple has intercourse, conception may take place Contraception helps to prevent conception from occurring Contraception methods do not eliminate the risk of STD’s Abstinence is the only contraception method that will 100% prevent pregnancy Methods of Family Planning Page 119

Infertility Infertility is the inability to become pregnant Affects both males and females Treatments Drugs Procedures Expensive Invasive Emotionally trying

Options for Infertile Couples Adoption Couple takes on all legal responsibilities of raising and loving and nurturing the child Artificial Insemination Doctor injects sperm into woman’s uterus Timed with ovulation Can have sperm donor In Vitro Fertilization Doctor combines ovum and sperm If ovum becomes fertilized, doctor places zygote in woman’s uterus If zygote attaches to uterine wall pregnancy takes place

Options for Infertile Couples Ovum Transfer Similar to in vitro but ovum has been donated Surrogate Mother Substitute mother becomes pregnant fo have a baby for another woman A lot of legal arrangement