Astigmatism in twin infants is related to pregnant nutrition

Astigmatism is a very common refractive error in infants. The etiology of astigmatism is poorly understood although it may involve pregnant environmental factors. The aim of this study was to examine the association between pregnant nutrition and the risk of infant astigmatism in twins. Total 28 pairs of twins (11 monozygotic and 17 dizygotic), whose mothers had been involved in this study since month 4-6 of pregnancy, received noncycloplegic refraction measurement by vision screening instrument at the age of 3 months. Detailed perinatal history and 24hour dietary records were collected. Umbilical vein blood of the twins and vein blood of their mothers in month 4-6 of pregnancy were collected to measure micronutrients, including vitamin A, 25-(OH) vitamin D3, calcium, iron, magnesium, and zinc. We found that he rate of astigmatism was significantly greater in twins from mothers with astigmatism than in those from mothers without astigmatism (P<0.01), but was not significantly associated with the mode of delivery, birth order, sex, birth asphyxia (P>0.05). Logistic regression analysis showed that morning sickness, BMD, Hb, maternal serum magnesium and vitamin A levels during mid-pregnancy, umbilical vein serum vitamin D3 and calcium levels and birth weight were correlated with astigmatism (P<0.05). In conclusion, the development of astigmatism in twins is related with pregnant nutrition and birth weight. Sufficient supply of nutrition during pregnancy may help prevent the development of astigmatism in twins.