When Kristin Cole of Montclair, New Jersey, became pregnant with her second child, she assumed things would go as smoothly as they had during her first pregnancy.
But shortly into her first trimester, she had a miscarriage. The next time she got pregnant, she miscarried again. And the time after that.
Though Cole was naturally devastated by her repeated losses, a seasoned obstetrician would not be particularly shocked by Kristin’s story. “Miscarriage is extremely common and in a sense should be considered a normal process of reproduction,” says Veronica Ravnikar, M.D., chair of the department of ob-gyn at Saint Barnabas Medical Center in Livingston, New Jersey.
While it’s true that 20 percent of all pregnancies end in miscarriage, it’s not much consolation when you’ve just had one. What is consoling, however, is the fact that the vast majority of women who’ve had miscarriages go on to have healthy pregnancies and healthy babies.
How Did This Happen?
“Although there’s very little one can say at the time that assuages the sadness, grief, blame and anger that women commonly feel in the days after a miscarriage, going over some of the statistics is helpful,” says Henry M. Lerner, M.D., author of Miscarriage: Why it Happens and How Best to Reduce Your Risks (Perseus, 2003). “The analogy I use is that it rains every fifth day in New England. You don’t ever look out the window and say, ‘But why is it raining?’ It just is–those are the statistics in nature. Yet, even after I explain all this, my patients ask me: ‘But why did it happen?’”
A miscarriage is defined as the spontaneous end of a pregnancy during the first or early second trimester; most occur within the first twelve weeks and some happen so early--before a missed period–that a woman never knows she was pregnant, never knows she miscarried. About 15 to 20 percent of miscarriages occur in the second trimester. A baby lost after twenty weeks is no longer considered a miscarriage, but a stillbirth.
What happens in a miscarriage is that—for one of several reasons described below—the fetus dies, pregnancy hormone levels start to fall, and tissue is expelled from the uterus, causing bleeding and cramping. If a woman does not expel all the tissue on her own, a procedure called a D & C (dilation and curettage) to scrape the uterus will remove it.
The most common reason for a miscarriage is a genetic mismatch called “chromosomal miscombination.” In normal pregnancies, when a sperm fertilizes an egg the chromosomes of the two cells fuse. But sometimes the chromosomes get scrambled, which means the blueprints for fetal development are faulty, and the fetus dies within the first few weeks of pregnancy. Approximately 60 to 80 percent of all miscarriages are thought to be due to this type of chromosomal error.
The other 20 to 40 percent of miscarriages are due to more tangible, physical causes, including infections, an abnormally-shaped uterus, inadequate hormone production, immunologic problems, or environmental toxins. These miscarriages usually occur later in the first trimester or in the second trimester.
While knowing why miscarriages occur is helpful, what most women who’ve suffered a miscarriage really want to know is how to prevent it from happening again. Because the most common cause of miscarriage—chromosomal—is considered a random event, women who have had one or even two first trimester miscarriages are usually advised to try and conceive again, and have faith that lightning won’t strike repeatedly. The chance that a woman will miscarry twice in a row is only 4 percent, and only 1 percent of women—like Kristin Cole—will miscarry three times. Because of these numbers, the standard medical protocol is to hold off on diagnostic testing until a woman has had three first-trimester miscarriages, a condition then identified as “recurrent miscarriage.”
