Pregnancy and Childbirth

Conception: The Incredible Journey  Our bodies are designed to promote pregnancy  During ovulation: A woman’s sexual desire peaks A woman’s sexual desire peaks A mucus plug in the cervix disappears A mucus plug in the cervix disappears Cervical mucus thins & creates gaps that vibrate with the sperm to aid motility and trap defective sperm; filters bacteria from semen Cervical mucus thins & creates gaps that vibrate with the sperm to aid motility and trap defective sperm; filters bacteria from semen  After ovulation, the lining of the uterus thickens, its glands become filled with nutrients, and small blood vessels enlarge to bring maternal nutrients to the embryo should pregnancy occur.

Conception: The Incredible Journey  Eggs can survive for about 24 hours.  Sperm can live for 72 hours; less than 1% can live up to one week  When a man ejaculates during sexual intercourse, hundreds of millions of sperm cells are released into the vagina. They make their way through the uterus and into the fallopian tubes, the usual site of fertilization.

After ovulation, the follicle moves through the Fallopian tube until it meets the spermatozoan. Fertilization takes place in the wide middle part of the tube called the ampulla. For some three or four days, the fertilized ovum remains in the Fallopian tube, dividing again and again. When the fertilized ovum enters the uterus, it sheds its outer wall in order to be able to implant in the wall of the uterus.

As the head of the spermatozoan enters the ovum, the ovum prevents penetration by another spermatozoan.

Conception: The Incredible Journey  Only one sperm fertilizes an ovum by secreting a chemical that makes a hole in the ovum coating  Immediately the ovum coating changes & does not permit further sperm from entering  Fertilization takes about 24 hours, usually in the ampulla  Zygote – a fertilized ovum (1 st Cell)

Conception: The Incredible Journey  During the first three days after fertilization, the cells of the embryo replicate at about daily intervals, and the embryo moves along the fallopian tube toward the uterus.  The zygote moves to the uterus, and on about the sixth day attaches to the lining of the uterus and shortly thereafter implants itself in the uterus and proceeds to develop as an embryo.  A uterine chemical dissolves the blastocyst coating, allowing implantation into the uterine wall, typically the upper portion.

Pregnancy  Soon after the embryo implants in the uterus, it secretes a hormone unique to pregnancy, called Human Chorionic Gonadotropin, or HCG, into the maternal bloodstream. This is the hormone detected in pregnancy tests and allows the pregnancy to be sustained.  The first noticeable signs of pregnancy: absence of the next menstrual period absence of the next menstrual period occasional nausea and vomiting - "morning sickness" occasional nausea and vomiting - "morning sickness" enlarged and tender breasts enlarged and tender breasts increased frequency of urination increased frequency of urination enlargement of the uterus enlargement of the uterus

Ectopic Pregnancy  On rare occasion, the fertilized egg implants outside the uterus, usually in the fallopian tube. A pregnancy in which the fertilized egg implants somewhere other than in the uterus (endometrial lining) is called an ectopic pregnancy.

In an ectopic pregnancy, the fertilized ovum implants outside the uterus. In most cases, it remains inside the Fallopian tube.

Conception: The Incredible Journey  Amnion – membrane covering the embryo that fills with protective fluid  Placenta – attached to the uterine wall, it aids the fetus in respiration, nutrition, excretion  Umbilical cord – connects fetus to placenta

Placenta & Umbilical Cord

The Prenatal Period: Three Trimesters  Fetal development occurs in two major phases. First phase: takes about 12 weeks; nearly all of the fetal body forms. By the tenth week of development, the fetal body appears to have a human form and weighs about 1 gram. First phase: takes about 12 weeks; nearly all of the fetal body forms. By the tenth week of development, the fetal body appears to have a human form and weighs about 1 gram. Second phase: takes about 28 weeks; the fetal body grows and many of the organs become functional. Second phase: takes about 28 weeks; the fetal body grows and many of the organs become functional.

Pregnancy  Pregnancy lasts 40 weeks, and each trimester is about weeks long  Healthy fetuses born after the normal day gestation period weigh between 5 and 10 pounds.  inches long  Prematurity vs. Low birth weight

First Trimester  1-13 weeks  The fetal heart forms and pumps blood by the end of the first month, as the circulatory system is the first to function  Other systems begin to develop: nervous, digestive, urinary, reproductive, appendages  Liver, kidneys, intestines, lungs begin developing by the end of this trimester  At the end, the fetus is ½ ounce & 3 inches  Ultrasound can detect the fetal heartbeat and image as soon as 5 ½ - 6 weeks

An embryo at 7 to 8 weeks. This embryo is approximately 1 inch long.

Second Trimester  weeks  Reflexes and tooth buds develop  Ultrasound may pick up gender around weeks  Movements can be felt by the mother  Lanugo and vernix cover the fetus to protect it from amniotic fluid  4 th Month movement felt  24 weeks hear and see  At the end, the fetus is 1¾ pounds & 13 inches

At five months, the fetus is becoming more and more lively. It can turn its head, move its face, and make breathing movements. This fetus is approximately 9 inches long.

Third Trimester  weeks  The fetus develops fat deposits, hiccups  The fetus can suck its thumb and react to light, pain, sounds  8 th month most organ systems are well developed, though the brain continues growing  At the end, the fetus is 7½ pounds & 20 inches  34 weeks survival probable

A fetus at nine months, ready for birth.

Giving Birth  A few weeks before the onset of childbirth, or labor, the fetus becomes positioned for birth by descending in the uterus, a process called lightening.  When this happens the pressure on some of the females internal organs is relieved and she may find it easier to breathe, stand, and digest food.  During the last half of pregnancy, a woman may at times feel her abdomen becoming hard or otherwise perceive the uterine contractions as they prepare her body for the true labor. Health professionals call these Braxton-Hicks contractions.

Childbirth and Labor  The onset of labor is marked by the appearance of strong, rhythmic, and eventually frequent uterine contractions. These initially dilate the cervix and later change in character to move the baby out of the mother's body.  The contractions of labor usually begin as roughly minute long contractions coming at approximately minute intervals. As labor progresses, contractions usually become more intense, frequent, and longer duration, perhaps up to 90 seconds.

Three stages of childbirth:  First stage: Effacement or thinning of the cervix occurs. Mother's cervix dilates to allow the baby to pass from the uterus; cervical opening enlarges from about 1 centimeter to about 10 centimeters to allow passage of the baby from the mother's body.  Second stage: baby moves into the birth canal. The actual emergence of the baby from the mother's body.  Third stage: called afterbirth; is the expulsion of the placenta.

 Ultrasound: high frequency sound waves create a picture of the fetus in the uterus. (sonogram)  Epidural  Breech position – the fetus has the feet or buttocks towards the cervix  Cesarean Section (C-Section) Delivery