Risk of severe maternal morbidity or death in relation to elevated hemoglobin A1c preconception, and in early pregnancy: A population-based cohort study

Autoři: Alexander J. F. Davidson aff001;  Alison L. Park aff001;  Howard Berger aff001;  Kazuyoshi Aoyama aff001;  Ziv Harel aff001;  Jocelynn L. Cook aff006;  Joel G. Ray aff001
Působiště autorů: University of Toronto, Toronto, Ontario, Canada aff001;  ICES, Toronto, Ontario, Canada aff002;  Department of Medicine, St. Michael’s Hospital, Toronto, Ontario, Canada aff003;  Department of Obstetrics and Gynaecology, St. Michael’s Hospital, Toronto, Ontario, Canada aff004;  Department of Anesthesia and Pain Medicine, the Hospital for Sick Children, Toronto, Ontario, Canada aff005;  Department of Obstetrics and Gynaecology, University of Ottawa, Ottawa, Ontario, Canada aff006;  The Society of Obstetricians and Gynaecologists of Canada, Ottawa, Ontario, Canada aff007
Vyšlo v časopise: Risk of severe maternal morbidity or death in relation to elevated hemoglobin A1c preconception, and in early pregnancy: A population-based cohort study. PLoS Med 17(5): e1003104. doi:10.1371/journal.pmed.1003104
Kategorie: Research Article
doi: 10.1371/journal.pmed.1003104



The relation between prepregnancy average glucose concentration and a woman’s risk of severe maternal morbidity (SMM) is unknown. The current study evaluated whether an elevated preconception hemoglobin A1c (A1c) is associated with SMM or maternal death among women with and without known prepregnancy diabetes mellitus (DM).

Methods and findings

A population-based cohort study was completed in Ontario, Canada, where there is universal healthcare. The main cohort included 31,225 women aged 16–50 years with a hospital live birth or stillbirth from 2007 to 2015, and who had an A1c measured within 90 days before conception, including 28,075 women (90%) without known prepregnancy DM. The main outcome was SMM or maternal mortality from 23 weeks’ gestation up to 42 days postpartum. Relative risks (RRs) were generated using modified Poisson regression, adjusting for the main covariates of maternal age, multifetal pregnancy, world region of origin, and tobacco/drug dependence. The mean maternal age was 31.1 years. Overall, SMM or death arose among 682 births (2.2%). The RR of SMM or death was 1.16 (95% CI 1.14–1.19; p < 0.001) per 0.5% increase in A1c and 1.16 (95% CI 1.13–1.18; p < 0.001) after adjusting for the main covariates. The adjusted relative risk (aRR) was increased among those with (1.11, 95% CI 1.07–1.14; p < 0.001) and without (1.15, 95% CI 1.02–1.29; p < 0.001) known prepregnancy diabetes, and upon further adjusting for body mass index (BMI) (1.15, 95% CI 1.11–1.20; p < 0.001), or chronic hypertension and prepregnancy serum creatinine (1.11, 95% CI 1.04–1.18; p = 0.002). The aRR of SMM or death was 1.31 (95% CI 1.06–1.62; p = 0.01) in those with a preconception A1c of 5.8%–6.4%, and 2.84 (95% CI 2.31–3.49; p < 0.001) at an A1c > 6.4%, each relative to an A1c < 5.8%. Among those without previously recognized prepregnancy diabetes and whose A1c was >6.4%, the aRR of SMM or death was 3.25 (95% CI 1.76–6.00; p < 0.001). Study limitations include that selection bias may have incorporated less healthy women tested for A1c, and BMI was unknown for many women.


Our findings indicate that women with an elevated A1c preconception may be at higher risk of SMM or death in pregnancy or postpartum, including those without known prepregnancy DM.

Klíčová slova:

Birth – Diabetes mellitus – HbA1c – Hemoglobin – Hypertensive disorders in pregnancy – Morbidity – Obesity – Pregnancy


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