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Periods, contraception and MS

MS affects more women than men and many women are diagnosed in their twenties and thirties.

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Menstrual periods and MS

Many women with MS say that their symptoms often feel worse before and during their periods. Symptoms most likely to be affected are balance, fatigue, depression and muscle weakness. 

MS symptoms often get worse when your body temperature goes up, for example during hot weather or if you have a fever. When you have your period your temperature can also go up, by about one degree Celsius. So this could be enough to make your MS symptoms feel worse. But they’ll get better once your temperature goes back down, after your period is over.

Some medications used to treat MS can have an effect on a woman’s menstrual cycle. These medicines include antidepressants that are in the class of drugs called SSRIs (selective serotonin reuptake inhibitors). Another drug that can affect periods is the group of DMTs called beta interferons. A beta interferon might cause irregular periods or 'spotting' (light bleeding) between periods. After several months of taking the treatment these side effects often improve on their own. But always mention any side effect you have to your MS nurse or neurologist.

It might be trickier to deal with your periods when you have MS. For example, you might struggle to use sanitary towels or tampons if you can’t move your arms, hands or legs like you used to, or if you now have a tremor. You might decide to try and control your periods. Several things might stop periods altogether, or make them less heavy. You could take a hormone-based contraceptive, or have a ‘coil’ fitted inside you, which is a kind of intrauterine device (UID).

Contraception and MS

In most cases MS won’t affect what kind of contraception a woman uses. That said, some types might be harder to use if MS is effecting how well you can use your hands, arms or legs. Also, women on a few drugs used to control MS must use contraception. That’s because if you became pregnant while on some disease modifying therapies (DMTs), the drug could harm your unborn baby.

For these reasons, it’s important that you talk to your neurologist or MS nurse about contraception or any plans to have a baby.

We need more research into MS and hormone-based contraceptives like ‘the pill’. Research we do have is mixed. Some studies found using these contraceptives made women no more likely to get MS, though one study found it did raise this risk. Others found that these contraceptives delayed the start of MS, while other studies found they made no difference. Again studies are mixed on whether hormone-based contraceptives make MS and its symptoms better or worse.

If you take a hormone-based contraceptive, you should be aware that some drugs make this type of birth control more likely to fail. Examples include Tegretol (carbamazepine), used for spasms and pain, phenytoin (Epanutin) used for severe MS-related pain, especially in the face, and also St John’s Wort (Hypericum extract), a herbal remedy for depression.

If MS means you can’t move around much, this might put you at greater risk of getting blood clots. Some oral contraceptives also raise your risk of clots so should be avoided if you’re not very mobile, or you may need extra monitoring for clots while using the contraceptive.

Contraceptives and MS drugs

Some DMTs might harm a baby in the womb, so you must avoid getting pregnant if you’re taking such a drug. If you want to get pregnant, you might need to stop taking your DMT or switch to a safer one. If you aren’t planning to have a baby and you’re on a DMT that can harm unborn babies,  it’s especially important that you use reliable contraception – like condoms or ‘the pill’.

Your neurologist or MS nurse can tell you which drugs should be avoided, which are less of a risk, and steps you need to take if planning to get pregnant. 

Our factsheets on each DMT look at how much of a risk they are to babies in the womb. Find the factsheet for the drug you’re interested in on our web page for that particular drug

If it’s your male partner who has MS and who is on a DMT, then there are two drugs where he must use contraception. These are teriflunomide (its brand name is Aubagio) and cladribine (brand name Mavenclad). With these, the drug can get on to his sperm, then into your body during sex, causing damage to your baby if you get pregnant. With cladribine (Mavenclad) this risk lasts for six months after the last time he took the drug, so he must use a condom for that time too.