Multiple sclerosis and women’s health – ECTRIMS 2015
European Committee for Treatment and Research in MS (ECTRIMS) – 31st Congress – Barcelona, Spain, October 7-10, 2015 – Women have a 2-3 fold higher risk of developing multiple sclerosis compared to men, which suggests that hormones influence the development of the disease. So a number of studies at this year’s ECTRIMS meeting examined different aspects of this MS-hormone connection.
Puberty: Entering puberty at a younger age appears to influence how MS will develop in women (but not in men). A U.S. study reported that earlier puberty was associated with MS symptoms at a younger age (Bove and colleagues. ECTRIMS 2015; abstract P804). On average, girls reached puberty when they were 12 years and six months old, and had their first MS symptom when they were 33 years and 10 months. For every six-month delay in reaching puberty, MS symptoms occurred about a year later (so if they reached puberty at age 13, their first MS symptom was at age 34, and so on). Previous studies have reported similar findings. A Canadian study found that MS symptoms began a year later for every one-year delay in puberty (Sloka and colleagues. Mult Scler 2006;12:333-339). A separate study found that later puberty was associated with a slightly lower risk of developing MS (Ramagopalan and colleagues. Eur J Neurol 2009;16:342-347).
It isn’t clear why early puberty would be associated with MS. It may be that female hormones trigger an inflammatory process that culminates in MS. Alternatively, earlier puberty may relate to childhood obesity, which has also been linked to the development of MS. A recent study found that girls with higher body weight at puberty typically developed MS symptoms at a younger age compared to girls of normal body weight (Kavak and colleagues. Mult Scler 2015;21:858-865). This may be due to the inflammatory effects of fat tissue.
Fertility: A study in Sweden looked at whether MS affects a woman’s fertility by examining national birth records (Fink and colleagues. ECTRIMS 2015; abstract EP1391). Overall, 17.5% of women with MS had more than two children compared to 23.5% of women in the general population. This translated to an 18.5% lower pregnancy rate among women with MS. However, it’s important to note that this difference may not mean that MS has a direct effect on a woman’s ability to get pregnant. The general view is that MS itself doesn’t affect a woman’s fertility (Hellwig K. Eur Neurol 2014;72 Suppl 1:39-42). So it may be that women with MS were more likely not to have children because they didn’t have a partner, or were concerned that their illness would affect their ability to rear a child. It may also be that women put off the decision to get pregnant because their MS is active, or they are taking a medication and don’t want to stop it.
Pregnancy: Pregnancy requires careful planning if you have MS because it’s best to avoid taking any MS medication during pregnancy and breast feeding. In some cases, however, MS is so severe that it may be best to continue treatment during pregnancy, so you’ll need to talk at length about your best options with your physicians and MS nurse.
Two studies have now reported on women who became pregnant after taking Lemtrada during clinical studies. Lemtrada is unusual in that the drug is gone from the body within a month or two after the last treatment, but its effects on the immune system are very long-lasting. So there’s a potential concern that these immune effects may affect the fetus.
To date there have been 193 pregnancies in the Lemtrada clinical development program (Achiron and colleagues. ECTRIMS 2015; abstract P1120). Among the 110 live births there have been no birth defects. The rate of spontaneous abortion was 22%, which was somewhat high but still within the normal range reported for women without MS (the normal range is 9-25% for healthy women 20-35 years of age). The average age of the Lemtrada group was 31 years when they became pregnant, which may have contributed to this rate since older women have a higher risk of spontaneous abortion. It’s recommended that you use effective contraception and wait at least four months after the last Lemtrada dose before trying to get pregnant. However, things don’t always go according to plan and in clinical studies there were eight pregnancies within four months of the last Lemtrada dose. Four births were normal, two women had spontaneous abortions, and one woman chose to have an abortion (one pregnancy is ongoing). A separate study reported that there were 20 pregnancies and 18 healthy babies born during open-label studies of Lemtrada (McCarthy and colleagues. ECTRIMS 2015; abstract P553). Two women had a miscarriage, but both went on to have two successful pregnancies each.
A separate study reported that Tysabri can cross the placenta during pregnancy, and can be found in breast milk in lactating women (Hainke and colleagues. ECTRIMS 2015; abstract EP1324). A previous study found that the amount of Tysabri appears to accumulate in babies as they continue to breast feed (Baker and colleagues. J Hum Lact 2015;31:233-236). The effects of this drug exposure on the baby’s health haven’t been determined.
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