# Beyond deficiency prevention: meteorological determinants and nonlinear associations of maternal vitamins D, A, and E with perinatal outcomes in 10,824 Chinese pregnancies

## TL;DR

This study explores how weather and vitamin levels in pregnant women in China affect birth outcomes, finding that both vitamin deficiencies and excesses are linked to complications.

## Contribution

The study identifies nonlinear and meteorological associations of maternal vitamin D, A, and E with perinatal outcomes, extending beyond deficiency prevention.

## Key findings

- Higher ambient temperature was linked to lower odds of vitamin D and A deficiencies.
- Vitamin A deficiency was associated with increased risk of PROM and macrosomia.
- U-shaped associations were found between vitamin levels and outcomes like low birth weight and macrosomia.

## Abstract

To examine meteorological factors associated with maternal vitamins D, A, and E and their associations with delivery and neonatal outcomes in central China.

In this retrospective cross-sectional analysis of 10,824 third-trimester women who delivered at 37 weeks or later in Wuhan (2020–2023), serum vitamin levels were measured by high-performance liquid chromatography. Daily temperature, humidity, precipitation, and wind speed were matched to individual blood collection dates. Multivariable logistic regression and restricted cubic spline models were used to evaluate associations with fetal distress, meconium-stained amniotic fluid, premature rupture of membranes (PROM), low birth weight, and macrosomia.

Vitamin D deficiency (30.2%), vitamin A deficiency (5.5%), and vitamin E excess (41.8%) were common. Each 1 °C increase in ambient temperature was associated with lower odds of vitamin D deficiency (aOR 0.970, p < 0.001) and vitamin A deficiency (aOR 0.976, p = 0.008), with significant temperature–humidity and temperature–wind interactions (p < 0.001). Vitamin A deficiency was associated with higher odds of PROM (aOR 1.76, 95% CI 1.44–2.14), whereas low or moderate vitamin D and A levels were associated with lower odds of fetal distress and meconium staining (aOR approximately 0.85, p < 0.05). Vitamin A deficiency was associated with markedly higher odds of macrosomia (aOR 3.14), and vitamin E excess was associated with a 60% increase in odds (aOR 1.60). Restricted cubic spline models revealed U-shaped associations between vitamin A and low birth weight, and between vitamin D and macrosomia.

Ambient temperature emerged as the primary meteorological factor associated with maternal vitamin status. Both deficiency and excess were associated with adverse delivery and neonatal outcomes, supporting the need for population-specific optimization beyond deficiency prevention.