|
"Miscarriage" is the lay term for the natural or accidental termination of a pregnancy at a stage where the embryo or the fetus is incapable of surviving. A pregnant woman Pregnancy is the process by which a mammalian female carries a live offspring from conception until it develops to the point where the offspring is capable of living outside the womb. ...
Categories: Biology stubs | Developmental biology ...
Fetus at eight weeks A fetus (alternatively foetus or fœtus) is an embryo in later stages of development, from the third month of pregnancy until birth in humans. ...
The medical term for it is "abortion"; when the abortion is not deliberately induced, it is termed a "spontaneous abortion," so that is a synonym for "miscarriage." Medically, all pregnancy losses prior to 20 weeks gestation are considered miscarriages or abortions.
Miscarriages are the most common complication of pregnancy. Abortion, in its most common usage, refers to the voluntary or induced termination of a pregnancy, generally through the use of surgical procedures or drugs. ...
Timing
Most such terminations occur very early in pregnancy, during the first trimester, and many people restrict the term "miscarriage" to early losses. Pregnancy losses in the second trimester are much less common.
Miscarriages frequently occur so early that the woman is not even aware that she is pregnant; these are preclinical pregnancy losses. Some women are prone to miscarry; the term "habitual abortion" is more and more replaced by "recurrent pregnancy loss" (RPL) and describes the condition where two or three consecutive pregnancies have terminated before 20 weeks gestation. For the term trimester used in academic settings, see Academic term The human gestation period of approximately 40 weeks between the time of the last menstrual cycle and delivery is traditionally divided into three periods of three months, or trimesters. ...
For the term trimester used in academic settings, see Academic term The human gestation period of approximately 40 weeks between the time of the last menstrual cycle and delivery is traditionally divided into three periods of three months, or trimesters. ...
Habitual abortions are repeated pregnancies that end in miscarriage of the fetus. ...
Types If a pregnant woman has vaginal bleeding, she is said to have a "threatened abortion", most patients with first trimester bleeding will be found to have a subchorionic hematoma and do well. In a minority such bleeding will progress to a pregnancy loss. With pain and opening of the cervix a woman is about to have an "inevitable abortion", which indicates that she has an absolute probability of miscarrying. Human female internal reproductive anatomy The vagina (from the Latin for sheath or scabbard ) is the tubular tract leading from the uterus to the exterior of the body in female mammals, or to the cloaca in female birds and some reptiles. ...
A threatened abortion is a type of miscarriage (aka abortion) that happens when there is bleeding with or without cramps or low back pain. ...
The abortion of a pregnancy is inevitable when any of the following symptoms are present: There is an obvious rupture of membranes An open cervix There is tissue in the cervix There is an absence of fetal heart at a βHCG level consistent with fetal heart activity When any of...
If some of the tissue remains in the uterus after a passing some tissue, this is called an "incomplete abortion". If the tissue in the uterus gets infected, it is a "septic abortion". In some cases the fetus dies, but the uterus does not expell the pregnancy:- this is called a "missed abortion". A "blighted ovum" pregnancy is a form of a miscarrage where the fetus either did not form, or died early, and the pregnancy consists only of trophoblastic tissue. An incomplete abortion is the miscarriage of a fetus in a pregnancy when tissue has been passed, but some remains in utero. ...
Miscarriage is the lay term for the natural or accidental termination of a pregnancy at a stage where the fetus is incapable of surviving. ...
An anembryonic gestation (aka blighted ovum) is a pregnancy in which a visible embryo never develops within a normal-appearing gestational sac, which likely occurs as a result of early embryonic death with continued development of the trophoblast. ...
A specific form of a miscarriage is the ectopic pregnancy. An ectopic pregnancy is one in which the fertilized ovum is implanted in any tissue other than the uterine wall. ...
Pathology When looking for gross or microscopic pathologic symptoms of miscarriage, one looks for the products of conception.
Microscopically, these include villi, trophoblast, fetal parts, and background gestational changes in the endometrium. Cytogenetic studies show that half or more of first trimester pregnancy losses have abnormal chromosome arrangements. Pathology (in ancient Greek pathos = pain/pation and logos = word) is the study of diseases. ...
The term conception can refer to more than one meaning: Concept Fertilisation This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ...
Villi (singular: villus) are tiny, finger-like structures that protrude from the wall of the intestine to help absorb nutrients in the lumen. ...
The trophoblast (from Greek threphein: to feed) is considered to be the first of all embryonic annexes. ...
The endometrium is the uterine membrane in mammals which is thickened in preparation for fertilization, and into which a fertilized egg is implanted upon its arrival into the uterus. ...
Figure 1: Chromosome. ...
Causes Miscarriages can occur for many reasons, not all of which can be identified. They are most frequent during the first trimester. About 30% of pregnancies are actually lost before the woman knows she is pregnant and may only be noticeable by slightly more important blood loss.
First trimester losses are in many cases due to aneuploidy. A chromosomal abnormality occurs where the genetic material from the sperm and egg do not fuse together appropriately. The resulting baby does not develop properly. In other cases, a "blighted ovum" occurs, where the water bag and placenta develop but not the fetus. Aneuploidy is a chromosomal state where abnormal numbers of specific chromosomes or chromosome sets exists within the nucleus. ...
The placenta is an ephemeral (temporary) organ present only in female placental mammals during gestation (pregnancy). ...
Other possible but much less common causes include physical trauma, exposure to certain chemicals, infection, and immune factors.
Pregnancy losses in the second trimester may be due to fetal abnormalities, uterine malformation, cervical problems, infection, trauma, immune factors, and medical disease.
Some conditions lead to recurrent pregnancy losses (recurrent spontaneous miscarriage or RSM). Often, doctors recommand an investigation after 3 or 4 losses and often find a cause for the recurrent miscarriages.
An uterine malformation (uterine septum) may cause about 15% of recurrent miscarriages. The uterine muscle is slightly malformed and the pregnancy cannot grow appropriately. The diagnosis is made by x-ray or ultrasound of the uterus. A uterine malformation is the result of an abnormal development of the Mullerian duct(s) during embryogenesis. ...
Some unusual vaginal infections can cause recurrent miscarriages, although it appears that this is not common.
Rarely (about 3% of the time), a chromosomal problem of one or both partners can lead to recurrent pregnancy loss. This is called "balanced translocation". Patients which such a chromosomal problem are more likely to miscarriage, though they can also deliver normal babies.
Another cause of recurrent miscarriage is autoimmune problem. In this case antibodies circulating in the blood stream attack cells and tissues within the body. In some cases, antibodies cause blood clots in the placenta, which shuts off the blood supply to the developing fetus, causing a miscarriage. This can be diagnosed by blood tests and treated with low dose aspirin. These situations are likely to increase risks for the foetus and such pregnancies are hence considered high risk.
Other possible causes are hormonal abnormalities.
During pregnancy the corpus luteum produces the hormone progesterone necessary for maintaining the pregnancy during the first trimester. Some doctors consider that a luteal phase defect may cause pregnancy to stop. This occurs when insufficient amounts of progesterone is present to act on the lining of the uterus. This is diagnosed by tissue sampling (from the uterine lining) and treatment is usually hormonal. The corpus luteum (Latin for yellow body) is a small, temporary endocrine structure in mammals that develops from an ovarian follicle after it has released a mature egg. ...
Progesterone is a steroid hormone involved in the female menstrual cycle, pregnancy (supports gestation) and embryogenesis of humans and other species. ...
Another potential cause for recurrent miscarriage is an allo-immune disorder, where the man and the woman have a lot of genetic material in common. This theory is extremely controversial.
Assessment Transvaginal ultrasonography has become the primary method of assessment of the health of an early pregnancy. Medical ultrasonography is an ultrasound-based imaging diagnostic technique used to visualize internal organs, their size, structure and their pathological lesions. ...
Management If a miscarriage is complete, and bleeding is contained and limited, only expectant management may be necessary. Excessive or prolonged bleeding needs medical attention. Often a dilation and curettage is indicated to remove tissue from the uterus. Tissue examination, including cytogenetic studies are helpful to determine the cause of the pregnancy loss. Febrile miscarriages need medical attention. Severe lower abdominal pain may indicate an ectopic pregnancy and needs medical attention. Dilation and curettage is a gynaecological procedure performed on the female reproductive system. ...
External links See also: childbirth, stillbirth, premature birth Childbirth in a hospital. ...
The expected result of pregnancy is the birth of a living child. ...
Premature birth is defined medically as a birth occurring earlier than 37 weeks. ...
| 
Feeds |
Contact