Could common steroid treatments be far safer during pregnancy than many assume? New research out of South Korea suggests that oral corticosteroids, long used to manage chronic and autoimmune conditions, may not carry the expected risk for gestational diabetes. But here's where it gets interesting—while the overall data look reassuring, there’s a small twist early in pregnancy that experts say deserves extra attention.
A nationwide cohort study involving over one million pregnant women found no significant link between oral corticosteroid (OCS) use and gestational diabetes risk overall. The research team, led by Ju-Young Shin, PhD, from Sungkyunkwan University in Seoul, discovered that when adjustments were made for various health factors, the potential risk all but disappeared (weighted RR 1.01; 95% CI 0.99–1.03). However, corticosteroid exposure between weeks 4 and 6 of gestation appeared to correlate with a slightly elevated risk (weighted RR 1.10; 95% CI 1.03–1.17). And this is the part most people miss—the timing of medication may be as important as the medication itself.
The study, published in JAMA Internal Medicine, analyzed data from South Korea’s National Health Information Database, including pregnancies that led to live births between 2010 and 2021. Out of roughly 3.8 million pregnancies, about 1.3 million met the eligibility criteria. Approximately 6% of these women were exposed to oral corticosteroids during the first 27 weeks of pregnancy. Gestational diabetes developed in 9.5% of the exposed group, compared with 7.36% among those unexposed.
Women with preexisting diabetes or gestational diabetes, or with missing pre-pregnancy health screenings, were excluded. The team divided the pregnancies into nine 3-week intervals (covering weeks 1–27) since gestational diabetes testing usually occurs before the 28-week mark. This granular approach allowed them to track corticosteroid exposure precisely over time.
Interestingly, although the two groups looked similar demographically, women exposed to corticosteroids had higher rates of certain conditions such as asthma (7.2% vs 2.2%), immune-related inflammatory diseases (2.5% vs 0.4%), and migraine (8.1% vs 5.4%). The average participant was between 30 and 34 years old, with a BMI between 18.5 and 22.9. These differences underline how corticosteroids are often used by patients with complex health needs.
To ensure robust results, the authors ran four additional sensitivity analyses—one focusing on women with a family history of diabetes, one on first-time pregnancies, one on singleton pregnancies, and one using past corticosteroid users as a comparison group. Across all variations, the findings remained consistent.
So why might that slight risk window at 4–6 weeks exist? The researchers suggest that early pregnancy is a hormonally critical period when the body prepares for changing insulin demands. The pancreas begins ramping up insulin-producing β-cell activity well before insulin resistance naturally develops later in pregnancy. Corticosteroids taken during this fragile phase might interfere with that adaptive process, potentially inducing mild insulin resistance earlier than usual and placing extra strain on the mother’s metabolism.
Of course, the study isn’t perfect. The authors caution that prescriptions don’t always confirm actual drug intake, and diagnostic codes for gestational diabetes introduce room for error. Moreover, since the cohort only included live births, certain unseen biases may exist. And can these results be confidently applied to other countries with different health profiles? That remains open for debate.
Still, the researchers emphasize an encouraging takeaway: when clinically necessary, oral corticosteroids appear metabolically safe for use in pregnancy. Physicians should continue prioritizing maternal health and disease control while monitoring blood glucose levels—especially for women already at higher risk.
These findings challenge some long-held concerns about steroid therapy during pregnancy. But what do you think? Should these results change how doctors counsel pregnant patients who need corticosteroids? Or does the early pregnancy risk mean we should still tread cautiously? Share your thoughts and experiences in the comments below—this conversation is far from over.
