The role of age
Closely tied to the incidence of chromosomal abnormalities in pregnancy is a woman’s age. “The likelihood of miscarriage increases exponentially as a woman gets older,” says Lesley Regan, M.D., director of the Recurrent Miscarriage Service at St. Mary’s Hospital in London and a clinical professor in the Division of Surgery, Oncology, Reproductive Biology and Anesthetics at Imperial College of London.
According to Hummel, a woman age 35 or younger has a 15 percent chance of miscarriage; as she nears 39, her chances are 20 percent. Risk increases to 30 percent at age 40 and to nearly 40 percent if she is 42 or older.
“At birth, a woman has all the eggs she’ll ever have,” Lerner explains. “The older she gets, the more time there is for her eggs to be damaged by such environmental insults as noxious chemicals, gases and heavy metals. This inevitable DNA deterioration over time could make the eggs’ instructions for growth unreadable.” Scientists now suspect that the father’s age—particularly if he is older than 40—may also be a factor in miscarriage, although a much smaller one than the mother’s.
The second most common cause of early losses are abnormalities in a woman’s body—most often her uterus, according to Hummel. “At least 30 percent of all miscarriages are due to anatomical factors within the uterus,” he explains. “Of these, fibroids are the biggest problem.”
Hummel points out that although these noncancerous tumors are extremely common in women of reproductive age, not all contribute to miscarriage. “The key is its location and size,” he says. The closer a fibroid is to the center of the uterus, where a fertilized egg is likely to implant, the more likely it is to cause a miscarriage; as for size, any fibroid larger than 5 centimeters (about 2 inches) can be problematic. Surgery to remove the fibroid is often extremely effective in reducing a woman’s risk of miscarriage without hampering her ability to conceive or carry a pregnancy to term, Hummel adds.
If you think you’re miscarrying
Unfortunately, there’s nothing you can do to stop a miscarriage once it starts. Nor should you want to, as the majority of losses are due to serious problems with the embryo or fetus.
The hallmarks of a miscarriage include heavy bleeding and cramping, as opposed to normal spotting, which occurs frequently in early pregnancy. This lighter spotting can be caused by implantation of the fertilized egg or by the developing placenta “digging” its roots into the wall and blood vessels of the uterus. “But half of the time, bleeding does indicate a miscarriage,” says Henry Lerner, M.D. “It’s a result of the fetus having died and the tissue starting to disintegrate. By the time you start bleeding, it’s already done—it usually takes seven to 10 days to see any bleeding.”
If you think you might be miscarrying, call your doctor or midwife. If you have in fact miscarried, she will want to make sure your body has completely expelled the tissue. If it hasn’t, you may need a procedure called a D&C to remove it. Coping with a loss A recent study found that women often suffer depression or anxiety for several years after a miscarriage.
If you need help, visit fitpregnancy.com/miscarriage for resources.