Jury still out on caffeine, miscarriages

Published: Tuesday, January 22, 2008 at 1:33 p.m.
Last Modified: Tuesday, January 22, 2008 at 1:33 p.m.

Women who have struggled through a miscarriage are often desperate for clues to what went wrong, and what they can do differently the next time. But doctors seldom have solid answers.

The latest research seems only to muddy the picture. A study by Kaiser Permanente in the American Journal of Obstetrics and Gynecology this week reports that women who consumed the equivalent of two cups of coffee or more daily had twice the miscarriage rate as those who avoided caffeine. Yet a study from Mount Sinai School of Medicine, in the journal Epidemiology this month, found that drinking more moderate amounts of caffeine didn't increase a woman's risk of miscarrying.

Either way, caffeine consumption is just one small piece of this heartbreaking puzzle for many couples. A host of other problems can sabotage a developing fetus, and if patients are aware of their options, they might be able to fill in at least a little of that puzzle.

Roughly one million pregnancies in the U.S. end in miscarriage every year, according to the National Center on Health Statistics. Most miscarriages occur in the first trimester, and some 60 percent are thought to be due to a random genetic error in the egg or the sperm or the first crucial cell divisions. No amount of prenatal care or dietary precautions will make a difference in these cases.

Even if the baby is genetically normal, other problems can doom the pregnancy. Some can be tested for, and treated, if doctors investigate. But they seldom do. The American College of Obstetricians and Gynecologists now recommends looking into possible causes after a woman has had two consecutive miscarriages. But because miscarriages are so common and so often thought to be genetically based, many OB/gyns still don't look for other explanations unless a woman has had at least three. And many insurers won't pay for tests to investigate "recurrent miscarriage" until a woman has had three.

In the meantime, the admonition is to "just try again" which can be very frustrating for couples to hear, particularly if they postponed childbearing and had trouble conceiving. And the chance of miscarrying gets higher after the mother reaches 35.

"You almost want something to be wrong so you can treat it," says Kelly Maguire, a counselor for Resolve, a support group for fertility issues, who had four miscarriages before having two healthy babies. "My experience is, it's all up to you and how much you push your doctor."

Among the things women can do to find explanations is to press for a genetic analysis of the miscarried tissue, if it's feasible to save. If it's abnormal, that alone will explain the miscarriage. But it's a good idea to seek genetic tests of both parents that could reveal whether the problem is likely to recur.

After a second miscarriage the mother should be tested for imbalances of hormones, including thyroid, prolactin and progesterone, as well as for polycycstic ovarian syndrome. Some are easily treatable. Autoimmune disorders such as antiphospholipid antibodies can cause blood clots that clog vessels in the placenta. Those may be treatable with baby aspirin and blood thinner. Bacterial infections, including some that linger for years with no symptoms, can also thwart pregnancy, and can be treated with antibiotics. A uterine abnormality may limit the space for the fetus. That can be seen on a sonogram, and in some cases, corrected by surgery.

To be sure, many recurrent miscarriages remain a mystery even after lengthy investigations. But that number is getting smaller all the time, says Jonathan Scher, a Manhattan OB/gyn who treats patients with recurrent pregnancy loss. "Patients who miscarry back to back should not take no for an answer. It's very old fashioned to accept 'it's nature way,'" he says. "Miscarriage doesn't always have to happen. Today, we can find answers in many cases, and in many cases, treatment is available."

In some cases, Dr. Scher even works with perinatal pathologists to seek clues from a patient's prior miscarriages if tissue from a D&C was sent to a pathology lab. Some states require such slides to be saved for years, and they can reveal traces of clotting problems or infection, as well as genetic problems.

How environmental agents might fit in is less well understood. But most OB/gyns have been telling pregnant women for years to go easy on caffeine, as well as to quit smoking and drinking alcohol and to avoid other hazards, such as cat litter and undercooked meat. As a result of the Kaiser study, the March of Dimes has lowered its recommended caffeine limit to 200 mg from 300 mg daily.

"Reducing caffeine won't prevent a miscarriage that's destined to happen," says Tracy Flanagan, Kaiser's director of women's health in Northern California. "But this does give women the opportunity to do something that may reduce their risk."

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