Association of prepregnancy body mass index and gestational weight gain on severity of optic nerve hypoplasia.

Background: Optic nerve hypoplasia (ONH) is a birth defect of unknown etiology and a leading cause of visual impairment in developed countries. Recent studies suggest that factors of deprivation and exposures of poor nutritional status, such as lower gestational weight gain (GWG), may be associated with increased risk of ONH. The present study describes the prenatal features of mothers of ONH cases, including prepregnancy BMI and GWG, and the associations with clinical features of disease severity.

Methods: Retrospective study of prenatal records for cases of ONH enrolled in a research registry. Prepregnancy BMI and GWG were compared to maternal characteristics and clinical findings of ONH severity including bilaterality, hypopituitarism, and neuroradiographic abnormalities.

Results: Compared to population-based normative data of births in the United States, mothers of ONH cases (n = 55) were younger (23.3 vs. 25.8 years; p = 0.03), with higher incidence of inadequate GWG (34.0% vs. 20.4%; p = 0.03) predominantly in the first and second trimesters. The presence of major brain malformations was associated with younger maternal age (21.6 [IQR 19.4, 24.7] vs. 24.9 years [IQR 22.1, 28.5] [p = 0.02]), primiparity (44.1% vs. 13.3%; p = 0.05) and decreased prepregnancy BMI (20.9 kg/m [19, 22.5] vs. 25.5 kg/m [21.3, 28.2]; p < 0.01).

Conclusion: Decreased prepregnancy BMI and inadequate GWG correlated with clinical features of ONH severity, specifically bilateral disease and presence of major brain malformations.