..... Click the link for more information. (conception) and birth birth or labor, delivery of the fetus by the viviparous mammal. Birth is also known as parturition. Human birth normally occurs about 280 days after onset of the last menstrual period before conception.
..... Click the link for more information. , during which mammals carry their developing young in the uterus (see embryo embryo (ĕm`brēō), name for the developing young of an animal or plant.
..... Click the link for more information. ). The duration of pregnancy in humans is about 280 days, equal to 9 calendar months. After the fertilized ovum is implanted in the uterus uterus, in most female mammals, hollow muscular organ in which the fetus develops and from which it is delivered at the end of pregnancy . The human uterus is pear-shaped and about 3 in. (7.
..... Click the link for more information. , rapid changes occur in the reproductive organs of the mother. The uterus becomes larger and more flexible, enlargement of the breasts begins, and alteration of renal function, blood volume, and blood cell count occur. Movement of the fetus fetus, term used to describe the unborn offspring in the uterus of vertebrate animals after the embryonic stage (see embryo ). In humans, the fetal stage begins seven to eight weeks after fertilization of the egg, when the embryo assumes the basic shape of the
..... Click the link for more information. and fetal heartbeat can be detected early in pregnancy.
One test that has been used to determine pregnancy uses blood or urine samples to detect a hormone known as BhCG, found exclusively in pregnant women. Later, prenatal diagnostic tests such as alpha fetoprotein, amniocentesis amniocentesis (ăm'nēō'sĕntē`sĭs)
..... Click the link for more information. , and chorionic villus sampling chorionic villus sampling (CVS) or chorionic villus biopsy (CVB) (kōr'ē-ŏn`ĭk, kôr'–)
..... Click the link for more information. may be performed as screening measures for congenital defects. Ultrasound ultrasound or sonography, in medicine, technique that uses sound waves to study and treat hard-to-reach body areas. In scanning with ultrasound, high-frequency sound waves are transmitted to the area of interest and the returning echoes recorded
..... Click the link for more information. , a sonar device using high-frequency wavelengths, is used to detect defects, measure fetal heartbeat, and monitor growth of a fetus.
Complications of pregnancy include eclampsia eclampsia (ĭklămp`sēə), term applied to toxic complications that can occur late in pregnancy.
..... Click the link for more information. , premature birth, and erythroblastosis fetalis erythroblastosis fetalis (ərĭth'rəblăstō`sĭs)
..... Click the link for more information. (Rh incompatibility). Ectopic pregnancy, in which the fetus begins to develop outside the uterus, often in a fallopian tube fallopian tube (fəlō`pēən)
..... Click the link for more information. , is another complication. It is often the result of scarring from a sexually transmitted disease sexually transmitted disease (STD) or venereal disease, term for infections acquired mainly through sexual contact. Five diseases were traditionally known as venereal diseases: gonorrhea , syphilis , and the less common granuloma inguinale,
..... Click the link for more information. . Smoking smoking, inhalation and exhalation of the fumes of burning tobacco in cigars and cigarettes and pipes. Some persons draw the smoke into their lungs; others do not. Smoking was probably first practiced by the indigenous peoples of the Western Hemisphere.
..... Click the link for more information. has been linked to low–birth weight infants; alcohol consumption during pregnancy has been linked to a group of defects called fetal alcohol syndrome fetal alcohol syndrome (FAS), pattern of physical, developmental, and psychological abnormalities seen in babies born to mothers who consumed alcohol during pregnancy .
..... Click the link for more information. .
The technology relating to pregnancy has made great advances and has created a number of ethical issues. Many women in their 40s are now able to sustain successful pregnancies, due to technological devices that carefully monitor the progress of the fetus. In vitro fertilization in vitro fertilization (vē`trō, vĭ`trō), technique for conception of a human embryo outside the mother's body.
..... Click the link for more information. and other infertility infertility, inability to conceive or carry a child to delivery. The term is usually limited to situations where the couple has had intercourse regularly for one year without using birth control .
..... Click the link for more information. treatments have allowed even postmenopausal women to give birth. The use of fertility drugs fertility drug, any of a variety of substances used to increase the possibility of conception and successful pregnancy. Different methods are used to correct or circumvent the many different functional disorders of both males and females that can interfere with
..... Click the link for more information. has led to a marked increase in multiple births multiple birth, bringing forth of more than one offspring at birth. Although many smaller mammals bear several young at a time, multiple births are relatively uncommon in humans and other primates.
..... Click the link for more information. . Abortion abortion, expulsion of the products of conception before the embryo or fetus is viable. Any interruption of human pregnancy prior to the 28th week is known as abortion.
..... Click the link for more information. , in which pregnancy is terminated prior to birth, has long been a subject of heated debate, and surrogate motherhood (see surrogate mother surrogate mother, a woman who agrees, usually by contract and for a fee, to bear a child for a couple who are childless because the wife is infertile or physically incapable of carrying a developing fetus.
..... Click the link for more information. ) has also raised ethical issues in recent years.
See also amenorrhea amenorrhea (āmĕn'ərē`a, əmĕn'–), cessation of menstruation .
..... Click the link for more information. ; birth defects; midwifery midwifery (mĭd`wī'fərē), art of assisting at childbirth.
..... Click the link for more information. .
Bibliography
See J. T. Queenan and C. N. Queenan, ed. A New Life (1992); C. A. Bean, Methods of Childbirth (1990);; Boston Women's Health Book Collective, Our Bodies, Ourselves for the New Century (1998).
pregnancy
)
pregnancy [′preg·nən·sē]
How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content.
| ?Page tools | ||
|---|---|---|
|