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March 02, 2010 March 02, 2010 *Every 28 days, an ovum, which is an egg cell, is released by one of the woman’s two ovaries. This occurs as part of the woman’s menstrual cycle, which is called ovulation. *At the same time the body prepares the uterus for fertilization, so it releases specific hormones. The uterus is the organ in the body where the baby develops in the event that the ovum is fertilized. *During ovulation the inner lining of the uterus grows and thickens. If the ovum is not fertilized, the lining breaks down and passes out the body. *When the ovum is released from the body it moves through the Fallopian tubes, which connects the ovary to the uterus. This movement usually takes 2-3 days. When the ovum reaches the uterus, it usually disintegrates and leaves the body with its menstrual flow. *In the event that the sperm or male cell reaches the Fallopian tubes, it may penetrate and fertilize the ovum. This process is called conception. *An ovum usually lives between 12-24 hours, while a sperm can try to fertilize for 48-72 hours. The sex of the child is determined. March 02, 2010 PRENATAL DEVELOPMENT IS CATEGORIZED INTO 3 STAGES (or trimesters) Stage I THE GERMINAL STAGE Prenatal development is the baby’s development during a pregnancy. *Formation of the zygote, which is the fertilized egg- this lasts 2 weeks and includes 2 key steps 1. Cell division- The zygote in the Fallopian tubes grow and the single cell splits into two cells, then into 4, then to 8, and so on 2. Implantation- lining of uterus thickens enough to provide a place for the zygote to attach itself and grow-after 2 weeks the zygote is the size of a pinhead. March 02, 2010 II. THE EMBRYONIC STAGE From now through the 8 th week of pregnancy the baby is called the embryo. *Embryo grows rapidly *During this stage the baby is called a fetus. 1. 20 buds for baby teeth appear. 2. Vocal cords develop. 3. Digestive system and kidneys begin to function 4. Movements are now possible (at end of 3 5. Fetus gains weight rapidly, uterus expands, and woman’s rd month) abdomen begins to grow more 6. Fat deposits begin to develop which will help maintain body heat after delivery. 7. Fetus takes on smooth skin 8. Stores nutrients and builds up immune system. 9. Fetus can: sneeze, kick, yawn, cough, hiccup, and cry. 10. Baby grows so much it cannot stretch out, so it positions itself into the fetal position. March 02, 2010 By the end of the first month, the embryo is about 1/10 of an inch long. The heart, which is no larger than a poppy seed, has begun beating. March 02, 2010 The embryo is about 1 inch long and has distinct, slightly webbed fingers. Veins are clearly visible. The heart has divided into right and left chambers. March 02, 2010 By now the fetus is 2 1/2 to 3 inches long and is fully formed. He has begun swallowing and kicking. All organs and muscles have formed and are beginning to function. March 02, 2010 *Longest stage and begins around the 8 or 9 th week and continues on to birth. *During this stage the baby is called a fetus. 1. 20 buds for baby teeth appear. 2. Vocal cords develop. 3. Digestive system and kidneys begin to function 4. Movements are now possible (at end of 3 rd month) 5. Fetus gains weight rapidly, uterus expands, and woman’s abdomen begins to grow more 6. Fat deposits begin to develop which will help maintain body heat after delivery. 7. Fetus takes on smooth skin 8. Stores nutrients and builds up immune system. 9. Fetus can: sneeze, kick, yawn, cough, hiccup, and cry. 10. Baby grows so much it cannot stretch out, so it positions itself into the fetal position. March 02, 2010 Your baby is covered with a layer of thick, downy hair called lanugo. His heartbeat can be heard clearly. This is when you may feel your baby's first kick. March 02, 2010 March 02, 2010 A protective coating called vernix begins to form on baby's skin. By the end of this month, your baby will be nearly 8 inches long and weigh almost a pound. March 02, 2010 Eyebrows and eyelids are visible. Your baby's lungs are filled with amniotic fluid, and he has started breathing motions. If you talk or sing, he can hear you. March 02, 2010 March 02, 2010 By the end of the seventh month, your baby weighs about 3 1/2 pounds and is about 12 inches long. His body is wellformed. Fingernails cover his fingertips March 02, 2010 March 02, 2010 Your baby is gaining about half a pound per week, and layers of fat are piling on. He has probably turned head-down in preparation for birth. He weighs between 4 and 6 pounds. March 02, 2010 March 02, 2010 Your baby is a hefty 6 to 9 pounds and measures between 19 and 22 inches. As he becomes more crowded, you may feel him move around less. March 02, 2010 A regular pregnancy lasts about 40 weeks or 280 days. *Physical Changes in mother: *Toward end of pregnancy baby’s weight shifts downward which is called lightening. The baby drops into the birth canal at this time. *Mother’s skin is stretched to capacity. *6 weeks after birth, mother returns to normal. *If baby’s head is downward, it makes birth much easier. *If baby is in an upright position, chances are high that the baby may have to be surgically removed which is called a cesarean section (c-section) March 02, 2010 *At the moment of conception, every baby receives 46 chromosomes, which are tiny threadlike structures in the nucleus of every cell. These chromosomes come in 23 pairs. The father’s sperm and the mother’s ovum each contribute. *Each chromosome has thousands of genes, which are units that determine a human’s inherited characteristics. *The complete blueprint for the creation of a person is called a genome. *Genes are made up of a complex molecule called DNA. A person’s 46 chromosomes form that person’s unique DNA. No two people expect identical twins have identical DNA. For every inherited characteristic, the person receives two copies of a gene- one from the mom and one from the dad. When genes are the same (both blue eyes) the child will automatically inherit that gene. *Dominant genes are stronger genes. *Recessive genes are weaker genes *Sex chromosomes come in 2 types (X and Y) *Female always carries an X. *Males carry either an X or Y. *If the sperm fertilizes the egg that is an X chromosome, the baby receives XX from the parents, making the child a female. *If the sperm fertilizes the egg with a Y chromosome, it makes the child an XY, which is a boy. March 02, 2010 Multiple Births- when the mother gives birth to more than one child. *The number of children that a woman will give birth to is determined at conception. *There are two types of multiple births. 1. Identical- always the same sex, children look the same and born at around the same time. 2. Fraternal- can be opposite sexes- children do not look alike and are still born around the same time. Identical Twins: When a sperm fertilizes the ovum, the cell begins to divide right away. As the cells continue to divide, the mass of cells may split in half, creating two separate masses. Each cell mass continues to grow on its own. Fraternal Twins: Form when 2 eggs are released form the ovaries at the same time and are fertilized by two different sperm. Because of the different eggs and sperm, fraternal twins may not look very much alike. 3 in 100 of all birth are twins. The chances of having identical twins are less than having fraternal. Out of 1,000 births, 23 will be fraternal twins 3 or more babies: Much more rare, however a rise in treatment to have children can increase the chance in frequency of multiple births. **The more children a woman carries the harder it is for all of the babies to survive. March 02, 2010 *Anytime a couple has sexual intercourse, conception may take place. There are many methods to prevent conception, which are called contraception. Contraceptives ABSTINENCE- 100% BIRTHCONTROL PILLS- 95-98% CERVICAL CAP-60-91% Small cervical cap that must be in place 8 hours before intercourse CONDOM- 86-97% Males or females can wear them-help reduce the spread of STDs DIAPHRAM-80-94% HORMONAL IMPLANTS-99% Capsules placed under skin in arm HORMONAL INJECTIONS-99% Given by physician monthly or once every 3 months- can cause irregular bleeding HORMONAL PATCH-99% Patch worn on skin for 3 weeks each month-similar to pills IUD-99% Inserted into woman- may cause discomfort NATURAL FAMILY PLANNING- RHYTHUM –53-80% SPERMICIDE- 72% Foams, creams, gels- should still be used with a condom VAGINAL IMPLANT-95-99% Ring worn internally for 3 weeks each month. March 02, 2010 -The inability to become pregnant OPTIONS FOR INFERTILITY1. Adoption 2. Artificial Insemination-doctor injects sperm into woman’s uterusprocedure takes time 3. In vitro fertilization- doctors combine a mature ovum from the woman with sperm from her husband. If the ovum becomes fertilized, the doctor places the new zygote in the woman’s uterusif the zygote attaches itself to the woman’s uterus, she becomes pregnant. 4. Ovum transfer- same as in vitro except the ovum comes from another woman (procedure is for women who lack working ovaries, poor ovum quality, or genetic disorders). 5. Surrogate mother- woman who becomes pregnant to have a baby for another woman- requires legal arrangements for all people involved March 02, 2010 4-3 Prenatal Problems *If a baby dies prior to the 20 th week, it is called a miscarriage. *If a baby dies after the 20 th week, it is called a stillbirth. *Unfortunately miscarries are very common- 15-20% of pregnancies end this way. * Stillbirth occurs in 2% of all pregnancies, because of problems with the placenta, abnormal chromosome problems, poor growth, and infections Birth Defects * Babies that survive pregnancy, but are born with serious problems that threaten their health or their life. *Approx. 150,000 babies around the world are born with birth defects each year. *CAN CAUSE: *Abnormalities of body structure *Blindness *Deafness *Mental retardation Causes of Birth Defects *Mother’s nutrition during pregnancy *Any diseases or infections mother had during pregnancy *Harmful substances mother consumes such as illegal drugs, alcohol, and OTC medicine *Exposure to hazards such as certain chemicals, radiation, x-rays HEREDITY *Every person has about 20,000-25,000 genes that not only determine things such as eye color, and hair color, but also the direct growth and development of every system in the baby. March 02, 2010 Heredity * Every person has about 20,000-25,000 genes that not only determine things such as eye Color, and hair color, but also the direct growth and development of every system in the baby. *Children normally get 5-6 imperfect recessive genes passed on to them that may have no effect on the development of the baby. *However sometimes the parents pass on the same recessive gene to the baby. * Sometimes a child inherits a bad gene that is dominant- it is only necessary that one parent have this gene to be passed on to the child. Chromosomal Errors *Several birth defects are caused by errors in the chromosomes. * An error may occur when an egg or a sperm is developing, causing a baby to have too few or too many chromosomes. * The most common chromosomal disorder is Down syndrome. 1 in 800-1,000 babies are born with it. This happens because the when the child is developing there is an extra pair of chromosome #21. Instead of carrying 2 copies of #21, the child has 3 copies. March 02, 2010 PREVENTION AND DIOGNOSIS OF BIRTH DEFECTS Genetic Counseling- people seek counseling to assess their risk of having a child with a birth defect that is caused by a defect in their genes Reasons: *If they have already had a child with a genetic birth defect and do not want to risk having another child with a defect. *If there is a gene that runs in the family and the family is not sure when it will pop up again Prenatal Tests 1. Alpha-fetoprotein (AFP) - a blood test is performed on mother who is 15-20 weeks pregnant. AFP is a protein in the mother’s blood that is produced in the liver and can indicate possible birth defects 2. Ultrasound- uses waves to make a video image of an unborn baby. It can help the doctor monitor the development of the baby, pinpoint the baby’s age, and detect certain birth Amniocentesis - process of drawing a sample of the amniotic fluid surrounding the unborn baby. This is used most often to detect Down’s syndrome or after questionable results from an AFP test, especially if the mother is over age 35. Chronic villi sampling- uses a sample of the tissue from the membrane that encases the fetus to check for certain birth defects. Samples of the tissue are snipped or suctioned off for testing- can be performed quite earl in the pregnancy. March 02, 2010 4-4 Avoiding Dangers to Baby ALCOHOL- is a drug that many people forget about. If the mother drinks, the alcohol is absorbed into the baby through the placenta- even a small amount can still harm the baby. *Fetal Alcohol Syndrome-is an incurable condition found in some children of mothers who consume alcohol during pregnancy. **1 in 5 babies born with FAS never see their first birthday. OTHER DRUGS*Medicines including prescription and OTC drugs *Caffeine-low birth weight (less than 5.8 lbs. *Nicotine- low birth weight, premature *Inhalants*Cocaine- SIDS (sudden infant death syndrome) that is the sudden death of a baby under one year old for no reason. *Ecstasy- heart disease, physical abnormalities Avoiding Dangers The first 3 months of pregnancy are most crucial b/c that is when the baby’s body systems are developing. OTHER THINGS TO AVOID: *X-rays-abnormalities *Paint-check with doctor before exposure *Pesticides used to exterminate bugs *Lead in water and paint *Carbon monoxide *Mercury- found in fish *Solvents, paint thinners, Other Risks to Fetus *Chicken Pox *Toxoplasmosis-infection caused by a parasite *STDs *AIDS *The following diseases can be passed from the mother to the baby: 1. Syphilis 2. Gonorrhea 3. Hepatitis B 4. Herpes 5. AIDS 6. Chlamydia