Pregnancy loss 1: The facts
October 6, 1999
Web posted at: 1:47 PM EDT (1747 GMT)
By Ann Douglas
(WebMD) -- This is the first in a two-part series on pregnancy loss.
It's a subject that prenatal classes tend to skip and expectant couples often ignore: the possibility that they could lose a pregnancy.
While it's only natural for pregnant women and their partners to want to focus on the excitement of being pregnant, it's important for those couples to realize that pregnancy loss is far more common than most people believe. Each year in the United States, approximately 1 million women experience a pregnancy loss, according to the American College of Obstetrics and Gynecology (ACOG) -- that's 25 percent of all pregnancies. Here's what all couples should know about pregnancy loss.
Miscarriage: The most common
Miscarriages are the most common type of pregnancy loss, occurring in approximately 15 percent to 20 percent of confirmed pregnancies, according to ACOG. Most miscarriages happen during the first 13 weeks of pregnancy, and the vast majority go unnoticed. They can occur up to the 20th week of pregnancy.
Most miscarriages are the result of chromosomal abnormalities in the developing embryo. In fact, about 7 percent of all pregnancy losses -- miscarriages or not -- have chromosomal abnormalities, according to the American Society for Reproductive Medicine (ASRM). Miscarriages can also be caused by a disease that a mother has developed. Some of these include:
- Lupus and other autoimmune disorders
- Severe kidney disease
- Uncontrolled diabetes
- Thyroid disease
- Intrauterine infection
There are also certain conditions and imbalances in a mother's body that can cause a miscarriage, including:
- Hormonal imbalances (for example, progesterone deficiencies)
- High levels of antiphospholipid antibodies (substances that can cause the blood vessels leading to the placenta to become clogged)
- Allogenic factors (when a woman develops antibodies to her partner's white blood cells)
- Anatomical factors (for example, uterine adhesions, an abnormally shaped uterus, uterine fibroids or an incompetent cervix)
- Recreational drug and alcohol use, as well as smoking
Research is focusing on the possibility that bacterial infections may be responsible for some first-trimester miscarriages. A study in this past July's British Medical Journal found that women with bacterial vaginosis had a significant increase in the rate of miscarriage in the first trimester. (Each of these women had been impregnated via in vitro fertilization.)
Age is also a significant risk factor for miscarriage. One reason a woman's risk rises with age is that women over 35 have a higher risk of chromosomal problems, according to ASRM, and a woman's body may spontaneously abort when a chromosomal abnormality develops.
Stillbirths: Causes sometimes unknown
"Stillbirths -- the death of a baby before birth -- occur in approximately 1 percent of births," says John Sussman, M.D., co-author of "Before You Conceive: The Complete Prepregnancy Guide." Unfortunately, more than half of stillbirths are unexplained, says Sussman, adding to the grief of bereaved parents. When it is possible to identify the cause of the baby's death, it is typically one of the following: a problem with the umbilical cord, a problem with the placenta, congenital abnormalities or maternal diseases (chronic hypertension, preeclampsia, metabolic diseases, Rh incompatibility, antiphospholipid antibodies, and certain viral and bacterial infections). Other babies are stillborn as a result of intrapartum death -- the loss of a baby during labor, typically due to a lack of oxygen.
Ectopic pregnancies: Detectable early on
Ectopic pregnancies -- in which the pregnancy occurs outside the uterus, most often in the fallopian tube -- occur in one out of every 60 pregnancies, according to ACOG. An embryo that implants in the fallopian tube is unable to grow any larger than a walnut before it causes the tube to burst -- something that may cause a medical emergency that can result in major bleeding or even maternal death.
Fortunately, ectopic pregnancies can often be diagnosed before a tube ruptures -- in fact, even before a woman has any symptoms, thanks to the use of quantitative HCG tests and transvaginal ultrasound. If a woman experiences pain on one side of her abdomen and in the shoulder region, vaginal bleeding and fainting, her caregiver may suspect that she is experiencing an ectopic pregnancy and order blood tests, a pelvic exam and/or ultrasound to confirm the diagnosis. If done in time, doctors can remove the ectopic pregnancy and avoid tubal damage.
The following increase a woman's risk for an ectopic pregnancy:
- A history of pelvic inflammatory disease
- Sexually transmitted diseases, such as gonorrhea and chlamydia
- Salpingitis (the inflammation of the fallopian tube)
- Having been treated for infertility
- Having had pelvic or abdominal surgery
- Using an intrauterine device at the time of conception
Molar pregnancies: The least common
Molar pregnancies, which result in the growth of abnormal tissue rather than an embryo, occur in just 1 out of every 1,500 to 2,000 pregnancies in the United States, reports ACOG. Molar pregnancies are more likely to occur in Asians than in members of other ethnic groups. Between 2 percent and 3 percent of women who have molar pregnancies develop cancerous cells that may require chemotherapy.
Ann Douglas is coauthor of The Unofficial Guide to Having a Baby (Macmillan).Copyright 1999 WebMD, Inc. All rights reserved.
RELATEDS AT :
American Society for Reproductive Medicine
American College of Obstetricians and Gynecologists
Note: Pages will open in a new browser window
External sites are not endorsed by CNN Interactive.
LATEST HEALTH STORIES:
China SARS numbers pass 5,000
Report: Form of HIV in humans by 1940
Fewer infections for back-sleeping babies
Pneumonia vaccine may help heart, too