Study Finds No Link Between Folate Intake and Risk for Preterm Birth

Barbara Boughton

February 16, 2011

February 16, 2011 (San Francisco, California) — One of the largest and most comprehensive studies to date on the effect of folate supplementation on preterm birth has found that the intake of this B vitamin has little effect on risk for premature delivery, according to research presented here at the Society for Maternal-Fetal Medicine 31st Annual Meeting.

The study of more than 19,000 singleton births in Norway assessed the effect of the dietary and supplementary intake of folate from 6 months before pregnancy through the beginning of the third trimester, but found that it was not significantly related to spontaneous preterm delivery, said lead researcher Verena Sengpiel, MD, PhD, from the Sahlgrenska University Hospital in Norway.

The investigators selected cases of preterm birth and control subjects from the Norwegian Mother and Child Cohort Study, which consists of nearly 73,000 children. Cases were defined as singleton live births with spontaneous onset of preterm delivery between 22 and 36 weeks of gestation, and controls were those who delivered between gestational weeks 39 and 40. Folate data were obtained from questionnaires completed by case and control mothers at gestational weeks 17, 22, and 30. The questionnaires included detailed questions on diet and the supplementary intake of folate.

"The critical period for folate supplementation is preconception through the first trimester. We hoped to confirm previous findings that folate supplementation could reduce risk for spontaneous preterm birth," Dr. Sengpiel said. "Our study was one of the most comprehensive studies done on the subject; no study has been published with as detailed information as we had on folate intake," she added.

Neither the amount of folate the women took previous to pregnancy or during it nor the time folate supplementation began was significantly associated with risk for preterm birth, Dr. Sengpiel noted. After dividing women into high and low dietary folate intake groups, the researchers found no significant association between folate intake and/or supplementation and preterm delivery in either group.

The study might have been limited by the fact that the researchers assessed folate intake only from 6 months before pregnancy, cautioned Alan Fleischman, MD, medical director of the March of Dimes, who chaired the session at which the study was presented. "Pregnancy is a short period of time. More and more we're concerned about preconception health as a method of preventing preterm birth," he said.

Previous studies that have found that folate intake decreases the risk for preterm birth have assessed intake of the B vitamin for a year before pregnancy, Dr. Fleischman said. In Norway, as in other European countries, foods are not fortified with folate as they are in the United States. "Yet some countries in Europe are considering adding folate to the food supply, including England and Ireland," Dr. Fleischman said. "In the United States, our approach has been to use the food supply in a positive way. But to many other cultures, adulterating the food supply is not an acceptable option," he said.

Dr. Sengpiel and Dr. Fleischman have disclosed no relevant financial relationships.

Society for Maternal-Fetal Medicine (SMFM) 31st Annual Meeting: Abstract 12. Presented February 10, 2011.


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