- Whether to continue lithium in pregnancy is a specialist, individualized decision made with your psychiatrist and OB, and not something to change on your own.
- Some studies suggest a small increase in the chance of heart defects with first-trimester use, especially a rare defect called Ebstein's anomaly, though other studies have not confirmed it.
- Lithium use is also associated with a higher chance of preterm birth, and newborns can have temporary symptoms, so monitoring around delivery matters.
- Blood levels are watched closely through pregnancy, and doses may need adjusting because the body handles lithium differently as pregnancy progresses and after birth.
- Untreated bipolar disorder carries serious risks in pregnancy and postpartum, and stopping lithium suddenly raises the chance of a serious relapse, so decisions are carefully managed.
- The old FDA pregnancy letter categories have been retired; questions about a specific exposure can go to MotherToBaby at 1-866-626-6847.
If you take lithium for bipolar disorder and you are pregnant or planning to be, you are facing one of the more carefully balanced decisions in medicine. Lithium has recognized considerations in pregnancy, but the condition it treats also carries serious risks if left unmanaged, and stopping suddenly can be dangerous. This article gathers what leading U.S. sources say so you can work through the choice with your specialist team. It is general education only and is not a substitute for that specialist care.
What lithium is and what it treats
Lithium is a mood stabilizer used mainly to treat bipolar disorder, both to manage episodes and to prevent them from returning. For many people it is highly effective and hard to replace, and it can be especially important for preventing relapse. Because bipolar disorder is a long-term condition and the weeks around childbirth are a high-risk time for episodes, decisions about lithium in pregnancy are almost always made and closely supervised by a psychiatrist working alongside your OB or a maternal-fetal-medicine specialist.
What the guidance says about pregnancy
MotherToBaby, a service of the non-profit Organization of Teratology Information Specialists, describes a nuanced picture rather than a simple verdict.
First-trimester heart defects
The concern people hear about most is a heart defect called Ebstein’s anomaly, in which one of the heart valves forms in an unusual position. MotherToBaby reports that some studies suggest a small increase in the chance of heart defects, including Ebstein’s anomaly, with first-trimester lithium use, while other studies have not confirmed this association. Importantly, even where an increased chance has been reported, this defect remains uncommon overall. MotherToBaby notes that detailed prenatal ultrasound, sometimes with a specialized fetal heart scan, can be used to screen for such defects.
Preterm birth and newborn effects
MotherToBaby reports that lithium use in pregnancy is associated with a higher chance of preterm delivery, meaning birth before 37 weeks. Newborns exposed near delivery can also show temporary symptoms, sometimes described together as effects on tone and alertness, including low muscle tone or “floppiness,” sleepiness, and trouble with breathing and feeding, as well as jaundice. These were more likely when the parent’s own lithium blood level was high around the time of birth. Effects on the baby’s thyroid have also been described. Most of these newborn symptoms are temporary.
Monitoring and dose changes
One reason lithium is so carefully managed in pregnancy is that the body handles it differently as pregnancy progresses. MotherToBaby notes that clinicians check lithium blood levels throughout pregnancy and may adjust the dose to keep it both effective and as low as reasonably possible. Levels and needs also shift quickly around delivery, so the plan often includes close monitoring at that time and in the postpartum period. This is detailed, hands-on care that only your treating team can tailor to you.
The other side: untreated bipolar disorder carries serious risks
It is essential not to read the risks above as a reason to simply stop. Untreated or undertreated bipolar disorder in pregnancy and after birth carries serious risks, including relapse into mania or severe depression, and the postpartum period is a particularly vulnerable time. Stopping lithium suddenly is well recognized to raise the chance of a serious relapse. Because of this, the choice is rarely “medicine versus no medicine” but rather how to treat the condition most safely. The American College of Obstetricians and Gynecologists (ACOG) addresses bipolar disorder in its guidance on perinatal mental health and emphasizes individualized treatment that weighs the risks of the illness alongside the risks of medication.
Do not stop or change on your own
This point deserves its own emphasis. Do not stop or change lithium on your own. Because abrupt discontinuation can trigger a serious relapse, and because the dosing needs careful, level-guided adjustment, any change should be planned and supervised by your psychiatrist together with your obstetric team. If you are worried about the medicine, the right step is to raise it with your specialist and plan together, not to stop the tablets and see what happens.
A note on the old letter categories
Older references sometimes assigned lithium an FDA pregnancy “category” letter. That system has been retired. U.S. drug labels now use a narrative format under the Pregnancy and Lactation Labeling Rule that describes what is actually known. If you find an old letter grade for lithium, treat it as out of date and ask your clinician for the current understanding.
Breastfeeding
MotherToBaby reports that lithium passes into breast milk, though usually at lower concentrations than in the parent’s blood, and that decisions about breastfeeding on lithium are individualized. Some clinicians support it with careful monitoring of the baby, weighing it against the strong benefit of preventing postpartum relapse. Because this is a nuanced call, decide it with your psychiatrist and your baby’s clinician.
When to call your OB or specialist
Stay in close contact with your psychiatrist and obstetric team throughout pregnancy if you take lithium, and reach out promptly if your mood changes, if you are considering any change to the medicine, or if you have symptoms of lithium being too high, such as marked tremor, confusion, vomiting, or unsteadiness. For questions about a specific exposure, call MotherToBaby at 1-866-626-6847, a free service that answers questions about medicines in pregnancy and breastfeeding. If you ever have thoughts of harming yourself, call or text 988 right away.
Frequently asked questions
Is lithium safe to take while pregnant? It is a carefully balanced, specialist decision. MotherToBaby describes some studied risks, but untreated bipolar disorder is also risky. Many people continue lithium under close monitoring; the right answer is individual.
What is the Ebstein’s anomaly risk? Some studies suggest a small increase in the chance of this rare heart defect with first-trimester use, while others have not confirmed it. It remains uncommon overall, and ultrasound can screen for it.
I took lithium before I knew I was pregnant. Should I worry? Try not to panic, and do not stop suddenly. Contact your psychiatrist and OB promptly so your treatment and monitoring can be reviewed together.
Can I just stop lithium to be safe? No. Stopping abruptly raises the chance of a serious relapse. Any change must be planned and supervised by your specialist team.
Why do my blood levels need checking so often? Pregnancy changes how your body handles lithium, so levels can shift. MotherToBaby notes clinicians monitor levels through pregnancy and around delivery to keep treatment safe and effective.
Can I breastfeed while taking lithium? It is individualized. Lithium passes into breast milk, and some clinicians support breastfeeding with monitoring. Decide with your psychiatrist and your baby’s clinician.
This article is general education, not medical advice, and must not be used to start, stop, adjust, or taper any medication on your own. Suddenly stopping some medicines can be dangerous. Always work with the prescriber who manages your care. In an emergency call 911; for mental-health crisis call or text 988.
Sources
- MotherToBaby (Organization of Teratology Information Specialists) — Lithium fact sheet.
- American College of Obstetricians and Gynecologists (ACOG) — guidance on treatment and management of mental health conditions during pregnancy and postpartum, including bipolar disorder.