Nutrition Intake and Retinal Microvasculature in Pregnant Women during the Mid-Late Pregnancy:

Abstract

Purpose: Both over-nutrition (e.g. high fat intake) and under-nutrition (e.g. low protein and carbohydrate intake) in the mothers during pregnancy may lead to reduced uterine-placental blood flows and eventually stunt fetal growth. The mechanism, of how maternal suboptimal nutritional problems affect utero-placental vasculature and further stunt utero-placental blood flow and fetal growth, is still unknown. Retinal microvasculature can be examined non-invasively and used as a reliable tool to assess microcirculature in vivo, thus, our study investigated the association between maternal nutrition intake and retinal microvasculature, which may indirectly reflect the uterine-placental circulation during pregnancy.

Methods: A total number of 1163 pregnant women aged 18-46 years were recruited during their early pregnancy to GUSTO birth cohort. Dietary intake was ascertained and retinal photography was performed at 26-28 weeks gestation. Intakes of protein, fat and carbohydrate (all in grams) were calculated based on an interviewer-administered 24-hour food recall. Healthy eating index (HEI) was scored from 0-100 within GUSTO cohort specific-intakes of different food components, and it was used to assess the dietary quality. Higher HEI score shows a better dietary pattern during pregnancy. Retinal vascular parameters were quantitatively measured by a semi-automated computer program (Singapore I Vessel Assessment [SIVA], version 3.0).

Results: There were 614 pregnant women in this study. In non-adjusted model, each unit increase in log-transformed protein intake and each 10-score increase in HEI was associated with a 6.08 µm (p=0.03) and a 1.23 µm (p=0.002) decrease in retinal venular caliber, respectively. After adjusting for age, ethnicity, maternal education, birth order, prenatal comorbidity, BMI at 26-28 weeks, smoking and alcohol drinking history and gestational diameter mellitus diagnosis, per 10 scores increase in HEI was marginally associated with a 0.93 µm (p=0.046) decrease in retinal venular caliber, yet the significance of unadjusted association between protein intake and retinal venular caliber narrowing was attenuated.

Conclusions: Our data suggest that mothers with better dietary quality tend to have smaller retinal venular caliber, which is an indicator of healthy retinal vasculature. These results provide insights into how maternal nutrition may affect the microvasculature in pregnancy.