Bipolar Medication and Pregnancy: How Lithium, Valproate, and Lamotrigine Differ
The three main mood stabilisers are handled very differently in pregnancy: lamotrigine is often continued, lithium is a case-by-case decision, and valproate is avoided in anyone who could become pregnant. With all three, one step carries serious risk: stopping suddenly on your own. This guide covers how each medicine is handled in Japan; the wider picture is in our guide to psychiatric medication in pregnancy.
Why is this planned rather than stopped suddenly?
Because untreated bipolar disorder is itself a serious risk in pregnancy. A relapse during pregnancy or after delivery can be severe enough to need hospital care and can endanger both mother and baby, and the months after birth are a high-risk period for relapse. Stopping a mood stabiliser makes relapse more likely, and stopping abruptly brings it on sooner.
The aim is a plan, ideally made before conception, that protects both your mood and the pregnancy. That can mean continuing the current medicine, switching to a safer one in good time, or occasionally pausing under close follow-up. Which path fits depends on your history and your medicine.
How is lamotrigine handled around pregnancy?
Lamotrigine (Lamictal) is often continued rather than switched, and Japan's bipolar disorder guideline (in Japanese) names it, alongside second-generation antipsychotics, as a lower-risk option in pregnancy. Its Japanese label (in Japanese) says it is given in pregnancy only when the benefit is judged to outweigh the risk, and that studies covering more than 12,700 pregnancies have not shown a real increase in major malformations with lamotrigine taken on its own, though some surveys reported more isolated cleft lip and palate.
Two practical points:
- Blood levels can fall during pregnancy, so the dose may need adjusting during pregnancy and again after delivery.
- The label says to avoid breastfeeding while taking lamotrigine, because a relatively large amount passes into milk. How that wording is weighed in practice is in our breastfeeding guide.
Our lamotrigine guide covers the medicine itself, including the slow start-up schedule.
Can lithium still be used in pregnancy?
Yes, in selected situations. Since a 2026 label revision, lithium is no longer contraindicated in pregnancy in Japan. The reason for caution remains: lithium can affect the baby's developing heart, so the current label (in Japanese) says it is not given unless it is judged unavoidable for treatment, and then only under a doctor experienced in treating bipolar disorder, working with a facility that can manage the pregnancy and the newborn.
Japan's bipolar disorder guideline suggests not using lithium in pregnancy unless other treatments, such as second-generation antipsychotics, have not worked. When it is used, blood levels are checked often, because pregnancy changes lithium levels. The label says to avoid breastfeeding on lithium, as meaningful amounts pass into milk.
If you take lithium and are thinking about pregnancy, have the conversation early, before conception if possible. The medicine itself is covered in our lithium guide.
Why is valproate treated so strictly?
Because valproate (Depakene) carries the strongest pregnancy warnings of the three. Taken in pregnancy, it causes major birth defects in roughly 1 in 10 babies, including spina bifida (where the spinal column does not close fully) and heart malformations. Children exposed in the womb have also scored lower on IQ tests at age six than children exposed to other epilepsy medicines, and have shown a higher rate of autism. Its Japanese label (in Japanese) therefore sets two rules:
- For bipolar disorder or epilepsy, it is not given in pregnancy unless judged unavoidable for treatment, and in anyone who could become pregnant the risks to a baby are explained before it is used. If you could become pregnant and are continuing valproate, talk with your doctor about pregnancy plans and contraception.
- For migraine prevention, one of valproate's other uses in Japan, it is contraindicated in pregnancy and is not used at all.
Japan's bipolar disorder guideline strongly recommends against using valproate in pregnancy, and advises people taking it to plan a change to another medicine before conception.
If you take valproate and discover you are pregnant, do not stop it on your own that day. Sudden withdrawal has its own risks, including relapse, and seizures if it is also treating epilepsy. Contact your doctor immediately; switches are planned, not improvised. More in our valproate guide.
What does planning 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 kept you well
- What a switch would cost you in stability
From there the plan is usually one of:
- Continue the current medicine with monitoring (common with lamotrigine; with lithium, under the conditions above).
- Switch in advance to a medicine with a better pregnancy record, allowing months to confirm that the new medicine keeps you steady (the usual path off valproate).
- Adjust around delivery, since dose needs often change in pregnancy and again after birth, and the months after birth need the closest follow-up.
If the pregnancy is already under way, the same logic applies on a shorter timescale, and the first step is to contact your prescriber this week rather than deciding 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 October 16, 2026.