Preconception hemoglobin A1c concentration in healthy women is not associated with fecundability or pregnancy loss

OBJECTIVE: To examine the relationship of preconception hemoglobin A1c, a marker of cumulative exposure to glucose over the preceding 2–3 months, with time to pregnancy, pregnancy loss, and live birth among fecund women without diagnosed diabetes or other medical diseases. DESIGN: A secondary analysis of a prospective cohort of women participating in the Effects of Aspirin in Gestation and Reproduction (EAGeR) trial. SETTING: Four US academic medical centers. PATIENT(S): A total of 1,194 healthy women aged 18–40 years with a history of one or two pregnancy losses attempting spontaneous conception were observed for up to six cycles while attempting pregnancy and throughout pregnancy if they conceived. INTERVENTION(S): Not applicable. MAIN OUTCOME MEASURE(S): Time to pregnancy, human chorionic gonadotropin pregnancy, clinical pregnancy, pregnancy loss, and live birth. RESULT(S): Although increasing preconception A1c level was associated with reduced fecundability (fecundability odds ratio [FOR] per unit increase in A1c 0.74; 95% confidence interval [CI] 0.57, 0.96) in unadjusted models and models adjusted for age, race, smoking and treatment arm (FOR 0.79; 95% CI 0.60, 1.04), results were attenuated after further adjustment for body mass index (FOR 0.91; 95% CI 0.68, 1.21). Preconception A1c levels among women without diagnosed diabetes were not associated with live birth or pregnancy loss. CONCLUSIONS(S): Among healthy women without diagnosed diabetes, we observed no association of A1c with live birth or pregnancy loss. The association between A1c and fecundability was influenced by body mass index, a strong risk factor for both diabetes and infertility. These data support current recommendations that preconception A1c screening should be reserved for patients with risk factors for diabetes. CLINICAL TRIAL REGISTRATION NUMBER: ClinicalTrials.gov: NCT00467363.