Hydroxychloroquine levels linked to maternal flares in pregnancy — July 2024

New research from July 2024 found something clear and useful: pregnant women with systemic lupus erythematosus (SLE) who had low hydroxychloroquine (HCQ) levels in the first trimester were more likely to experience severe maternal flares. The same study showed those low levels did not meaningfully raise the risk of bad pregnancy outcomes like preterm birth or fetal loss. That’s a big deal — it points to a specific effect on the mother’s disease activity rather than the baby’s outcomes.

What this means for pregnant women with SLE

If you’re pregnant and taking HCQ for SLE, this study suggests paying attention to blood drug levels early in pregnancy. Why? Because low HCQ in the first trimester was tied to worse maternal flares later on. That doesn’t mean HCQ causes problems — rather, not having enough in your blood seems to let SLE become active. Many doctors already recommend continuing HCQ during pregnancy because it usually helps control disease and is considered safe for the fetus.

Practical steps you can take right now: ask your rheumatologist or obstetrician about a blood HCQ level check in the first trimester; confirm you’re on the right dose; discuss adherence if you miss doses; and review other meds or supplements that can affect absorption. If levels are low, your care team can investigate why — missed doses, faster drug clearance during pregnancy, or interactions — and decide on an adjustment.

Signs of a flare and quick actions

Know the common flare signs so you catch them early: increased joint pain or swelling, new rashes, fever, unexplained fatigue, or new kidney issues. If you notice these, contact your rheumatologist right away. Typical responses include adjusting medications, closer monitoring, or short-term steroids — always guided by a specialist who knows pregnancy-safe options.

Also, keep prenatal visits and labs on schedule. SLE in pregnancy needs teamwork: rheumatology, obstetrics, and sometimes nephrology or maternal-fetal medicine. Share any medication side effects or missed doses with your team so they can act before a flare becomes severe.

This July post doesn’t change the basic advice that many specialists already give: continue HCQ during pregnancy unless a clinician tells you otherwise. What it does add is evidence to support monitoring HCQ levels early on to reduce the chance of severe maternal flares. If you have SLE and are planning pregnancy or already pregnant, bring this up at your next appointment — asking for a first-trimester HCQ level can be a simple step with potentially big benefits for your health during pregnancy.

Read the full post for study details and talk to your care team about what testing and dosing plan fits your situation.