Epilepsy and contraception

If you're taking anti-seizure medication and are a man who can father children or a woman of child-bearing age, it's important that you talk to your healthcare provider about contraception.

Some anti-seizure medicines, such as sodium valproate and topiramate, can harm your unborn baby. The risk of harm to the baby from anti-seizure medicine use during pregnancy is highest in the first trimester (first 12 weeks of pregnancy), before many people realise they're pregnant. Read more about epilepsy and pregnancy.

Some anti-seizure medicines, such as carbamazepine and phenytoin, are enzyme-inducing medicines. This means they increase the activity of certain enzymes in the liver that break down other medicines such as the oral contraceptive (the pill) and the contraceptive implant. This makes these types of birth control less reliable, which can increase your risk of having an unplanned pregnancy.

This is why it's best to use 2 forms of contraception, usually one of the options in the section below on how well contraception works plus condoms. 

If you're taking an oral contraceptive, make sure you know what to do if you miss a dose, or if you're sick with vomiting (being sick) or diarrhoea (runny poo/hamuti).

Intrauterine devices (IUDs) and medroxyprogesterone acetate injection (Depo Provera) aren't affected by anti-seizure medicine.

While condoms aren't affected by anti-seizure medicine, they are the least reliable birth control if used by themselves. They're more effective if used with another method of contraception. 

Intrauterine device (IUD)

• Very reliable – fewer than 1 in every 100 people who use an IUD (1%) become pregnant during 1 year of typical use.
• It's not affected by anti-seizure medication.
• An IUD is a small, T-shaped plastic device that's put into your uterus (womb) and has a thread tied to the end which hangs down through the cervix into your vagina.
• In Aotearoa New Zealand, there are 2 types of IUDs: progestogen or hormonal IUDs (Mirena®, Jaydess®) and copper IUDs. Read more about IUDs.

Medroxyprogesterone acetate injections (Depo Provera)

• About 3 in every 100 people who use Depo Provera (3%) become pregnant during 1 year of typical use.
• It's not affected by anti-seizure medication.
• Depo Provera is given as an injection, every 13 weeks (about every 3 months). 
• Read more about Depo Provera.

Progestogen-only implant

• Very reliable – fewer than 1 in every 100 people with a progestogen implant (1%) become pregnant during 1 year of typical use.
• This option is NOT recommended if you're taking enzyme-inducing medicines such as carbamazepine, phenytoin, phenobarbital, primidone or topiramate.
• The contraceptive implant is made up of 2 small rods (about the size of a matchstick) that contain progestogen. These rods are placed under your skin, on the inside of your arm (you can feel the rods under your skin). Read more about implants.

Combined hormonal oral contraceptive (COC) pill

• About 8 in every 100 women (8%) become pregnant during 1 year of typical use.
• This option is NOT recommended if you're taking enzyme-inducing medicines such as carbamazepine, phenytoin, phenobarbital, primidone, topiramate or the anti-seizure medication lamotrigine.
• For it to be effective you have to take the COC pill every day, whether you have sex on that day or not.

• If you're taking an oral contraceptive, make sure you know what to do if you miss a dose, or if you're sick with vomiting (being sick) or diarrhoea (runny poo/hamuti). Read more about the combined hormonal oral pill.

Progestogen-only pill (POP)

• About 8 in every 100 people who take the POP (8%) become pregnant during 1 year of typical use.
• This option is NOT recommended if you're taking enzyme-inducing medicines such as carbamazepine, phenytoin, phenobarbital, primidone or topiramate.
• For it to be effective you have to take the POP every day.  Read more about the progesterone-only pill.

Condoms

• Very unreliable – about 15 in every 100 people who use condoms (15%) become pregnant during 1 year of typical use.

The ‘morning after pill’ is a form of emergency contraception that can be taken within 72 hours after sex. It can be used if you have unprotected sex, if you've missed a dose of the pill or if a condom breaks.

• Some anti-seizure medication can affect the morning-after pill, eg, carbamazepine, phenytoin, oxcarbazepine, phenobarbital, primidone, rufinamide, topiramate.
• Because the medicines above interact with the morning after pill, you may need to take double the dose of the morning after pill just to be safe. However, this is an unapproved dose and the effectiveness of this option has not been fully studied.
• A copper IUD is recommended for emergency contraception for people taking these anti-seizure medicines.
• Read more about emergency contraception and how do I choose the right emergency contraception for me?

Non-hormonal contraceptive methods (eg, condoms, diaphragms, and IUDs) don't affect seizure control.

The effect of hormonal contraception (eg, the combined oral contraceptive, mini pill or progestogen only pill) and implants on seizure control varies among people using these methods.

• Some people find that hormonal birth control increases their number of seizures while others find it decreases their seizures, or has no effect on their seizures at all.
• If you're not sure how your birth control method will affect your seizures, look for signs that your anti-seizure medication isn't working, such as changes in the number, length, or kind of seizures you usually have. Talk to your healthcare provider about this.

If you decide you'd like to get pregnant, it's important to plan your pregnancy 6 to 12 months before you start trying to get pregnant.

Anti-seizure medicines can harm an unborn child and the risks are higher with some medicines, combinations of medicines and at higher doses.

Talk to your healthcare provider and agree on a plan about how to manage your anti-seizure medicines and your dose.

Read more about planning for pregnancy, how medicines for epilepsy, mental health and pain can harm your unborn baby(external link) and epilepsy medicines and pregnancy.(external link)

Folic acid

Folic acid tablets are recommended from 4 weeks before, to at least 12 weeks after conception to reduce the risk of harm to your baby from neural tube defects.

A higher than usual dose of folic acid (5 mg per day) is recommended for people taking anti-seizure medicines.

Folic acid reduces the risk of harm from neural tube defects but doesn't reduce other harmful effects of anti-seizure medicines to the baby.

Read more about folic acid.