Lithium & Pregnancy: What you need to know

Lithium has been a trusted treatment for mood disorders for over 70 years. It’s especially effective in stabilising mood and preventing relapses, making it a cornerstone of treatment for Bipolar Disorder and Treatment-Resistant Depression.

But what happens when pregnancy enters the picture?

Many women and healthcare providers are understandably cautious about lithium use during pregnancy.

However, it’s essential to balance these concerns with the risks of untreated mental illness, which can be equally, if not more, serious for both mom and baby.

In this post, we’ll break down the facts about using lithium during pregnancy—its benefits, risks, and how to navigate treatment safely.

Why Lithium?

Lithium is primarily used for:

• Bipolar Disorder (especially Type 1): Proven to treat and prevent manic episodes
• Treatment-Resistant Depression: When other treatments haven’t worked
• Suicide Prevention: Recognised for its ability to reduce suicidal thoughts
• Postpartum Psychosis Prevention: Often used as a preventive measure in women with a history of postpartum psychosis

Challenges of Lithium use during pregnancy

While lithium is effective, it’s not usually a first-line treatment in pregnancy due to several factors:

• Narrow Therapeutic Range: The difference between a therapeutic and toxic dose is small, requiring regular blood tests to ensure safety.
• Health Risks for Mom: Lithium can affect the thyroid, kidneys, and metabolism, sometimes leading to weight gain, tremors, or nausea.
• Potential Impact on Baby: Lithium is a known teratogen (a substance that can cause birth defects), though the risks are lower than once believed.

Understanding Risks for Baby

1. Congenital Anomalies

• Some studies suggest lithium increases the risk of heart defects, but recent research indicates that the risk is much lower than previously thought. The estimated additional risk is about 1 extra case per 100 live births.
  At lower doses (under 600 mg/day), the risk is close to that of the general population.

2. Neonatal Complications

• Some babies exposed to lithium in utero may require longer hospital stays or specialised neonatal care, though there’s no evidence of long-term developmental delays or IQ differences compared to non-exposed babies.

How to safely use Lithium during pregnancy

If lithium is the best treatment option for you, here’s how to minimise risks and ensure a healthy pregnancy:

1. Preconception Planning

Before pregnancy, it’s important to:

• Confirm your diagnosis and treatment history
• Evaluate previous episodes & response to lithium
• Weigh the risks of lithium use vs. the risk of untreated illness

2. Risk-Benefit Counseling

• Informed decision-making is key—understanding both the risks of taking lithium and the risks of stopping it.
• Work with your doctor to create a personalised treatment plan that suits your needs.

3. Team-Based Care

• Pregnancy and mood disorders are complex—having a multidisciplinary team (psychiatrist, obstetrician, pediatrician) ensures comprehensive care.

4. Careful Monitoring

• Baseline health checks before starting lithium (basic blood tests, ECG, etc.)
• Regular blood tests to adjust lithium levels as needed
• Fetal ultrasound scans to monitor baby’s health

Other Important Considerations

Pregnancy Changes Lithium Levels

• As pregnancy progresses, your body processes lithium differently, which may require dose adjustments to prevent toxicity or relapse.

Breastfeeding & Lithium

• Breastfeeding is not usually recommended, as lithium can accumulate in a newborn’s system, increasing the risk of side effects.

Postpartum Period & Lithium

• The first few weeks postpartum are high-risk for relapse in bipolar disorder, making close monitoring and lithium adjustments crucial.
• For women with previous postpartum psychosis, starting lithium immediately after birth can be a preventive strategy.

While lithium use during pregnancy comes with unique challenges, it remains a life-changing treatment for many women with severe mood disorders. Untreated mental illness can pose serious risks to both mother and baby, so decisions should be made carefully with expert guidance.

With the right monitoring, planning, and support, lithium can be used safely—helping mothers maintain stability and ensuring the best outcomes for both mom and baby.

If you’re considering pregnancy while on lithium, talk to your doctor to create a plan that works for you!