Australian Study Reveals Hidden Blood Sugar Danger in Common Pregnancy Treatment

A study from Australia is raising important questions about a routine pregnancy intervention and its surprising effects on blood sugar — even in women who have never had diabetes.

What the Research Looked At

Researchers at Western Health and the University of Melbourne conducted a comprehensive scoping review, analyzing 14 studies — including 12 observational cohort studies and 2 randomized controlled trials — to examine how antenatal glucocorticoids affect blood sugar levels in pregnant women without diabetes. These steroid medications (betamethasone or dexamethasone) are routinely given to pregnant women at risk of preterm delivery to help the baby's lungs mature before birth. The review was published in the Journal of Gynecology Obstetrics and Human Reproduction in 2025.

What They Found

The results were striking: every single study reviewed reported elevated blood sugar — clinically called hyperglycemia — in women without diabetes after receiving these steroid injections. The prevalence ranged from 54% to 95% of women affected. In plain terms, as many as 9 out of 10 women without any prior diabetes diagnosis experienced abnormally high blood sugar after receiving these routine shots.

To put those numbers in US-friendly context, hyperglycemia during pregnancy is generally defined as blood glucose exceeding 140 mg/dL (7.8 mmol/L) one hour after a meal, per American Diabetes Association (ADA) guidelines for gestational diabetes management. The steroid-induced spikes documented in these studies pushed many women well beyond that threshold — temporarily, but significantly.

Researchers also noted that while three of the reviewed studies used insulin to treat the elevated blood sugar, dosing approaches varied widely and there was no clear picture of whether treatment improved outcomes for mothers or newborns.

The Newborn Connection

A secondary concern the Australian team investigated was whether a mother's steroid-induced high blood sugar increases the risk of neonatal hypoglycemia — dangerously low blood sugar in the newborn baby. This is a known risk when mothers with gestational diabetes have poorly controlled glucose near delivery. However, the current evidence was insufficient to confirm or rule out this link in women without diabetes. The researchers concluded that larger, multi-center trials are urgently needed.

Why This Matters for US Patients

In the United States, antenatal glucocorticoids are a standard of care for women at risk of preterm birth before 34 weeks, as recommended by the American College of Obstetricians and Gynecologists (ACOG). Tens of thousands of American women receive these injections every year — the vast majority of whom do not have a diabetes diagnosis at the time of treatment.

This Australian research suggests those women may be experiencing significant, unmonitored blood sugar spikes during a critical window of fetal development. Currently, there are no US guidelines recommending glucose monitoring for non-diabetic women receiving these steroids. If the blood sugar spikes are large enough to affect fetal outcomes, that gap in care could matter enormously.

For US patients and their care teams, the key takeaway is this: if you are pregnant, at risk for preterm birth, and your doctor recommends steroid injections for fetal lung maturity, it is entirely reasonable to ask about blood sugar monitoring — especially if you have risk factors like obesity, a family history of diabetes, or a previous large baby.

The Bottom Line

This Australian research does not suggest women should avoid these life-saving steroid injections. Fetal lung maturation remains critically important. But it does signal that medicine may need to pay closer attention to what happens to maternal blood sugar in the days following treatment — and that current protocols may have a meaningful blind spot.

Source: Jones, Lee, Kevat. "Maternal glycaemic responses to antenatal glucocorticoids: a scoping review." Journal of Gynecology Obstetrics and Human Reproduction (2025). DOI: 10.1016/j.jogoh.2025.103029. PMID: 40935291.