A to Z of MS Contraception

There are no reasons why women with multiple sclerosis should not use oral contraceptives. As some drugs, including antibiotics, modafinil, phenytoin and carbamazepine, may reduce the effect of oral contraceptives, it is recommened that women talk to their doctor before starting treatment. People with limited mobility may need extra monitoring as there is an increased risk of blood clots occurring in the veins in the legs.

Good manual dexterity is needed for the use of barrier contraceptives, such as diaphragm, condoms and spermicides; hand tremor or weakness could cause problems. Using a diaphragm may increase the risk of bladder infections.

Intrauterine devices (IUD) have been shown to be generally safe, effective and easy to use. Hormone-releasing IUDs have become available and have the advantage of reducing menstrual flow and duration. There is some evidence that antibiotic or immunosuppressive drugs may reduce the effectiveness of the IUD.

Another option is a progesterone implant, again requiring no maintenance and effective for up to five years. Progesterone can also be injected on a three monthly basis.

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Oral contraceptives and the risk of developing MS

The fact that multiple sclerosis is more frequent in women than men and that pregnancy generally seems to have a beneficial effect on the condition suggests that hormones may modify the risk of MS.

Researchers compared the medical records of 106 women with MS with those of 1001 women who had not developed MS. They found that women who had used oral contraceptives in the previous three years were 40% less likely to develop MS than those who had not. They also found that the risk of developing MS increased in the six months following pregnancy, but was not otherwise related to bearing children.

The researchers conclude that the hormonal changes that occur whilst using oral contraceptives and in pregnancy may reduce the risk of MS in the short-term, and that the period immediately following childbirth may be associated with a short-term increase in the risk of developing MS.

The authors draw attention to other factors that may have influenced the results, such as a pregnancy during the follow-up period or whether those using the pill were 'healthy' individuals (eg not smokers or overweight), but feel that the study demonstrates the need for more research into the link between hormones and MS.

In a subsequent review comparing results from several studies, the same researchers concluded that oral contraceptives did not affect the risk of developing MS but could delay the onset of multiple sclerosis.

References

Alonso, A et al.
Recent use of oral contraceptives and the risk of multiple sclerosis.
Archives of Neurology 2005;62(9):1362-1365.
abstract

Alvaro A, et al.
Oral contraceptives and the risk of multiple sclerosis: A review of the epidemiologic evidence.
Journal of Neurological Sciences 2009;286:73-75.
abstract

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