A new research review strengthens the evidence that women with multiple sclerosis are about as likely as other women to have a healthy pregnancy—without putting their own health at risk.
The findings, reported in the obstetrics journal BJOG, support the advice generally given to women with multiple sclerosis: If the condition is under control, you can safely become pregnant.
"A woman with multiple sclerosis can consider pregnancy just the same way all other women consider it," Dr. Yara D. Fragoso, a neurologist at the Universidade Metropolitana de Santos in Brazil, and the senior researcher on the new study, told Reuters Health.
Multiple sclerosis, or MS, is a nerve disorder thought to arise when a person's immune system mistakenly attacks that person's own nerve fibers. MS leads to symptoms like muscle weakness, numbness, vision problems and difficulty with coordination and balance.
Years ago, women with MS were advised to avoid pregnancy, partly out of concern that it could make their disease worse.
But studies in recent decades have shown that the opposite is true; many women see their symptoms improve or even disappear during pregnancy -- possibly because immune system activity naturally declines and levels of anti-inflammatory hormones called corticosteroids naturally rise during pregnancy.
Recent studies have also suggested that women with MS are at no special risk of pregnancy complications.
For the new review, Fragoso's team pulled together 22 international studies conducted since the 1980s, involving more than 13,000 women.
Combining those results, they found that women's MS symptom flare-ups were slightly less common during pregnancy, and slightly more common for a short time after pregnancy.
But during pregnancy, and in the 12 months before and after, the rate of symptom flare-ups, known as relapses, never exceeded 1 per year.
It's been known that MS relapses often increase in the few months following delivery. But that's not thought to raise a woman's long-term risk of disability.
As far as pregnancy complications, Fragoso's team found that women with MS did not have a higher risk of miscarriage, preterm birth, having a low-birthweight baby or having a newborn with a birth defect.
For instance, from country to country, preterm delivery rates ranged from about 9 in 100 to 11 in 100, similar to what would be expected for the general population.
A recent U.S. study that involved more than 10,000 pregnant women with MS was by far the largest included in the analysis. In that study, 42 of every 100 women with MS had a cesarean section, versus about 33 of every 100 other U.S. women.
But there could be "cultural and geographical influences" at work when it comes to C-section, according to Fragoso's team. In a few other studies that looked at C-section rates among women with MS, the figure ranged from about 9 out of 100 to 17 out of 100.
Overall, Fragoso told Reuters Health in an email, MS does not appear to have a "negative effect on the pregnancy and/or child, nor does the pregnancy seem to negatively affect the course of multiple sclerosis in the long term."
It's still important for women with MS to work with their doctor when planning a pregnancy. One reason is that they may need to stop taking their MS medication. The so-called disease-modifying drugs are not approved for use during pregnancy, and research suggests that at least one, beta-interferon, may be associated with miscarriage.
And throughout pregnancy, Fragoso said, a woman's neurologist and obstetrician should work together.