HbA1c May Be Useful Screening Test For Pregnant Women With Unrecognized Diabetes

Dr. Janet Rowan Obstetric Physician National Women's Health, Auckland

Dr. Rowan

MedicalResearch.com Interview with:
Dr. Janet Rowan

Obstetric Physician
National Women’s Health,
Auckland

Medical Research: What is the background for this study?

Dr. Rowan: Clinicians are interested in screening during early pregnancy to identify women with previously unrecognised diabetes, as these women have increased risks of adverse pregnancy outcomes. HbA1c is a simple and reproducible measure of glucose elevations, but its usefulness as an early pregnancy screening test is not clear. The aim of this study was to examine whether pregnant women with an HbA1c of 41-49mmol/mol (5.9-6.6%) are a high risk subgroup and whether treating these women from early pregnancy improves outcomes compared with identifying them during routine screening for gestational diabetes (GDM) from 24 weeks’ gestation.

This observational study compared women referred to the diabetes clinic <24 weeks’ who had an early pregnancy HbA1c of 41-49mmol/mol (5.9-6.6%) with women who, at the time of diagnosis of GDM ≥24 weeks’ (typically by 75gOGTT), had an HbA1c of 41-49mmol/mol (5.9-6.6%). Both groups were compared with women diagnosed with GDM who had a lower HbA1c at diagnosis.

Medical Research: What are the main findings?

Dr. Rowan: The study showed that, compared with women with a lower HbA1c, women with an HbA1c of 41-49mmol/mol (5.9-6.6%) were higher risk for adverse pregnancy outcomes, with higher BMI and need for medication. Women with a higher HbA1c treated <24 weeks’ (n=134) had similar outcomes to women with a lower HbA1c (n=661). Women with a higher HbA1c treated ≥24 weeks (n=151) had more preeclampsia, preterm births and neonatal admissions than women with a lower HbA1c. Women with HbA1c 41-49mmol/mol (5.9-6.6%) treated from early pregnancy had significantly lower rates of preeclampsia that those treated ≥24 weeks, but other outcomes were not significantly different.

Medical Research: What should clinicians and patients take away from your report?

Dr. Rowan: This study demonstrates to clinicians that HbA1c may be a useful early pregnancy screening test for identifying women who enter pregnancy with significant unrecognised glucose elevations. It suggests early intervention may reduce risks of adverse pregnancy outcomes. However, small numbers and observational design limit conclusions.

Medical Research: What recommendations do you have for future research as a result of this study?

Dr. Rowan: Further research is required to confirm whether early intervention improves pregnancy outcomes compared with later intervention and, if so, the optimal HbA1c threshold for early referral.

Citation:

Women with an HbA1c of 41-49 mmol/mol (5.9-6.6%): a higher risk subgroup that may benefit from early pregnancy intervention.

Rowan JA, Budden A, Ivanova V, Hughes RC, Sadler LC.
Diabet Med. 2015 May 29. doi: 10.1111/dme.12812.

PMID: 26031320

Dr. Janet Rowan (2015). HbA1c May Be Useful Screening Test For Pregnant Women With Unrecognized Diabetes