Bipolar Medication and Pregnancy: How Lithium, Valproate, and Lamotrigine Differ
The three main mood stabilisers sit at completely different points on the pregnancy map: lamotrigine is often continued, lithium is a careful case-by-case decision, and valproate is avoided in anyone who could become pregnant. Across all three, the most dangerous move is the same one: stopping suddenly on your own.
If you have bipolar disorder and a pregnancy is planned, possible, or already here, this guide walks through how each medicine is handled in Japan. It's the detailed companion to our broader guide to psychiatric medication in pregnancy.
Why is this a planning conversation, not an emergency stop?
Because untreated bipolar disorder is itself a serious risk in pregnancy. Relapse during pregnancy or after delivery, especially a manic or mixed episode, can endanger both mother and baby, and the months after birth are among the highest-risk periods for relapse in all of psychiatry. Stopping a mood stabiliser abruptly is one of the strongest known triggers.
So the goal is never "medication or baby." It's finding the plan, ideally before conception, where both mood and pregnancy are protected. Sometimes that means continuing the current medicine, sometimes switching to a safer one in good time, and occasionally pausing under close follow-up. All three paths exist; which one fits depends on your history and your medicine.
How is lamotrigine handled around pregnancy?
Lamotrigine (Lamictal) is frequently the mood stabiliser of choice when pregnancy is on the horizon, and it is often continued rather than switched. Large international pregnancy registries haven't shown a clear rise in major malformations, which is why doctors tend to keep it running.
Two practical points:
- Blood levels drift during pregnancy, so the dose may need adjusting along the way and again after delivery.
- Breastfeeding is the more cautious conversation with this particular medicine: unusually much passes into milk, so that decision is made individually with your doctor.
Our lamotrigine guide covers the medicine itself, including the slow start-up schedule.
Can lithium still be used in pregnancy?
Yes, in carefully selected situations; as of the 2026 label revision, lithium is no longer formally contraindicated in pregnancy in Japan. The reason for the old caution still stands, though: lithium can affect the baby's developing heart, so the current standard is that it isn't used unless treatment truly requires it.
In practice, that means lithium in pregnancy is possible but structured: it's reserved for situations where lithium is clearly the medicine that keeps you well, with closer monitoring of blood levels, which shift as pregnancy changes how your body handles the drug. Breastfeeding on lithium is generally avoided, as meaningful amounts pass into milk.
If you're on lithium and thinking about pregnancy, have the conversation early, before conception if at all possible. Details on the medicine are in our lithium guide.
Why is valproate treated so strictly?
Because valproate (Depakene) carries the strongest pregnancy warnings of any medicine we prescribe. Taken in pregnancy, it causes major birth defects in roughly 1 in 10 babies, including spina bifida (where the spinal column doesn't close fully) and heart malformations. Children exposed in the womb also show higher rates of learning difficulties and autism spectrum conditions as they grow. Because of that:
- In anyone who could become pregnant, valproate is avoided wherever possible and used only when other options haven't worked, always alongside reliable contraception.
- For migraine prevention, one of valproate's other uses in Japan, it is formally contraindicated in pregnancy: for that purpose it isn't used at all.
One thing matters just as much as the warnings: if you're taking valproate and discover you're pregnant, don't stop it on your own that day. Sudden withdrawal has real risks of its own, including relapse, and seizures if it's also covering epilepsy. Contact your doctor immediately instead; switches are planned, not improvised. More in our valproate guide.
What does planning actually look like?
Three questions, then one of three plans. A typical pre-conception conversation covers how severe and how recent your episodes have been, which medicine has actually kept you well, and what the switch options would cost you in stability. From there the plan is usually one of:
- Continue the current medicine with monitoring (common with lamotrigine, structured with lithium).
- Switch in advance to a pregnancy-compatible option, allowing months to confirm the new medicine holds you steady (the usual path off valproate).
- Adjust around delivery, since dosing needs often change in pregnancy and again postpartum, and the postpartum months deserve the closest follow-up of all.
If the pregnancy is already underway, the same logic applies on a faster clock, and the first step is always the same phone call: your prescriber, this week, not a decision made alone at home.
Frequently asked questions
This article is general information, not medical advice for your individual situation. Decisions about medication in pregnancy belong in a consultation with a doctor who knows your history.
Medically reviewed by our psychiatrist (M.D.). Updated July 29, 2026.