NEW YORK (Reuters Health) – By increasing the risk of premature rupture of membranes (PROM), very low maternal vitamin C levels may lead to preterm birth, according to research presented this week at the annual meeting of the Society for Maternal-Fetal Medicine in New Orleans.
"Vitamin C plays a role in the structure of collagen in the fetal membrane, and when it's not there, it makes the membrane weaker," lead author Dr. Anna Siega-Riz, from the University of North Carolina at Chapel Hill, told Reuters Health.
The researchers assessed vitamin C's effects in 2247 pregnant women who were enrolled in a study funded by the National Institute of Child Health and Human Development. The women were given a questionnaire asking them to detail their intake of various foods before pregnancy as well as during their second trimester.
The investigators found a strong relationship between a lack of vitamin C in a woman's diet and a tendency toward PROM.
Women who were in the bottom 10th percentile for vitamin C intake before pregnancy had twice the risk of PROM that other women had. Similarly, women who were in the bottom 10th percentile for vitamin C intake during the second trimester were at 70% increased risk of PROM.
The researchers controlled for several factors that could contribute to membrane rupture, such as cigarette smoking, age and race. But other factors could be responsible for the association seen in the study, Dr. Siega-Riz noted. For example, women with high vitamin C intake tend to be in better health and have better overall nutritional habits.
"This is another study that shows there is a potential for a causal pathway for vitamin C leading to rupture of membranes, which needs to be verified with randomized, clinical trials," Dr. Siega-Riz said.
The researchers found that only 28% of the women said they had taken vitamin C supplements before pregnancy, while 80% reported taking a multivitamin by the 30th week of pregnancy. The current findings suggest that starting vitamins after becoming pregnant is not enough to ward off rupture risk.