Quinine is not considered safe for casual use during pregnancy, but it remains an accepted treatment for malaria in pregnant women when the benefits outweigh the risks. The distinction matters: quinine prescribed by a doctor to treat a life-threatening malaria infection is very different from quinine taken for leg cramps or consumed in tonic water. For non-malaria uses, there is no safety data supporting quinine in pregnancy, and medical guidelines advise against it.
Quinine for Malaria: When It’s Still Used
Malaria during pregnancy carries serious risks of maternal and infant death, so treatment is essential. The CDC lists quinine combined with clindamycin as one of the accepted options for treating uncomplicated malaria in pregnant women, particularly during the first trimester when some newer treatments have historically had less safety data. Treatment courses last three to seven days depending on where the infection was acquired.
For the second and third trimesters, artemisinin-based combination therapies (ACTs) are now preferred by the WHO because they work faster, are better tolerated, and have accumulated enough human safety data to be considered at least as safe as quinine. A systematic review published in The Lancet Infectious Diseases found that ACTs had better efficacy and tolerability than quinine in pregnant women, and the evidence supporting quinine as a first-choice drug even in the first trimester is increasingly questioned. Still, in many low-resource settings, quinine remains available when other drugs are not, and it continues to be used when the alternative is leaving malaria untreated.
Quinine for Leg Cramps: No Safety Data
Outside of malaria, quinine is sometimes prescribed for severe nocturnal leg cramps that haven’t responded to other treatments. Leg cramps are common in pregnancy, which may lead some people to wonder whether quinine could help. The answer is straightforward: there are no studies evaluating quinine for leg cramps during pregnancy, and it is not recommended for this purpose. The UK Teratology Information Service (UKTIS) states explicitly that no data exist on this use in pregnant women and recommends specialist consultation before any exposure.
Even in non-pregnant adults, regulatory agencies including the FDA have warned against using quinine for leg cramps due to the risk of serious side effects, including dangerous drops in blood platelet counts and heart rhythm problems. Adding pregnancy to this equation only increases the concern.
Known Risks to the Developing Baby
Quinine crosses the placenta and can affect fetal development. Case reports have documented serious outcomes following quinine overdose during pregnancy, including stillbirth, congenital deafness, underdevelopment of the optic nerve, and abnormalities of the central nervous system, limbs, face, and heart. These reports are largely associated with doses well above the therapeutic range, but they illustrate that the drug is not inert to the fetus.
At therapeutic doses used for malaria treatment, the picture is more nuanced. A meta-analysis published in PLOS Medicine found that pregnancies treated with quinine during the first trimester had a 48% higher risk of miscarriage compared to pregnancies not treated with any antimalarial drug. However, the researchers noted this elevated risk may partly reflect the malaria infection itself rather than the drug: quinine’s seven-day dosing schedule and unpleasant side effects (ringing in the ears, nausea) lead to poor compliance, meaning the underlying malaria may not be fully treated, which itself raises miscarriage risk.
Quinine can also stimulate insulin release, which may cause dangerously low blood sugar. Pregnant women are already more prone to low blood sugar during malaria infections, and quinine can make this worse, particularly in late pregnancy. Blood sugar monitoring is standard practice when quinine is given to pregnant patients in a clinical setting.
Hearing and Vision Concerns
Quinine is known to be ototoxic, meaning it can damage structures in the inner ear. In adults, quinine-related hearing loss is typically temporary and resolves after the drug is stopped. The concern during pregnancy is different: the developing fetal ear and optic nerve may be more vulnerable. Case reports of congenital deafness and optic nerve damage have been documented after maternal quinine exposure, though these are primarily linked to overdose situations rather than standard therapeutic doses.
If you’ve had a brief, prescribed course of quinine for malaria during pregnancy, the risk of these outcomes at normal doses appears to be low. UKTIS recommends additional fetal monitoring when exposure occurs above therapeutic levels, especially during the first trimester.
Tonic Water and Dietary Sources
Tonic water contains quinine, though at much lower concentrations than a medicinal dose. A typical serving of tonic water has roughly 20 to 80 milligrams of quinine, compared to the 500 to 600 milligrams taken three times daily for malaria treatment. While occasional tonic water is unlikely to deliver enough quinine to cause the adverse effects seen at therapeutic or toxic doses, there is no established safe threshold during pregnancy. Most medical guidance suggests avoiding it or limiting consumption, simply because there is no benefit that would justify even a small, uncertain risk.
What This Means in Practice
The safety of quinine in pregnancy depends entirely on why it’s being used. For malaria, it is an accepted treatment because untreated malaria poses a far greater danger to both mother and baby than the drug itself. For anything else, including leg cramps, the risk-benefit calculation doesn’t hold up: there are no studies confirming safety for non-malaria uses, and the known pharmacological effects of quinine on the uterus, blood sugar, and fetal development make it a poor choice when safer alternatives exist.
If you were exposed to quinine early in pregnancy before knowing you were pregnant, or if you’ve been taking it for leg cramps, the most useful step is to stop and let your prenatal care provider know. A single exposure or short course at normal doses is unlikely to cause harm based on the available evidence, but your provider can arrange appropriate monitoring, particularly an ultrasound to check fetal development, if the timing or dose warrants it.