Folic acid supplementation in early pregnancy and the risk of preeclampsia, small for gestational age offspring and preterm delivery.
OBJECTIVE
To assess whether folic acid intake during the first trimester of pregnancy is related to pregnancy outcomes preeclampsia, low birth weight or preterm birth.


METHODS
Prospective cohort study of 3647 women who were followed from the first trimester of pregnancy. Detailed information on quantity of folic acid intake before and during the first three months of pregnancy was recorded. Pregnancy outcome data were abstracted from obstetric records.


RESULTS
Lean mothers who used folic acid supplementation the month before pregnancy had a 40% reduced risk of developing preeclampsia. The adjusted odds ratio (OR) with 95% confidence intervals (95%CI) for preeclampsia in lean mothers (BMI<25) who used folic acid supplements the month before pregnancy was 0.6 (95% CI 0.4-1.0). Obese mothers who used folic acid supplementation in the first trimester had an increased, but not statistically significant risk for preterm birth (adjusted OR 1.9 with 95% CI 0.9-4.0). There were no significant associations between folic acid supplementation and low birth weight.


CONCLUSIONS
Our study supports a possible protective effect of folate intake in early pregnancy on preeclampsia in lean mothers. There was no support for any beneficial effect of folic acid use on preterm birth or low birth weight, and we found no evidence of any harmful effects of folate use for the outcomes included in our study.
Department of Obstetrics and Gynecology, St. Olav's University Hospital, Trondheim, Norway; Department of Laboratory Medicine, Children's and Women's Health, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway. Electronic address: marit.martinussen@ntnu.no.
Marit P
MP
Martinussen
Yale Center for Perinatal, Pediatric and Environmental Epidemiology, Yale University, New Haven, CT, USA.
Michael B
MB
Bracken
Mandell Center for Multiple Sclerosis and Neuroscience Research, Mount Sinai Rehabilitation Hospital, St. Francis Care, Hartford, CT, USA.
Elizabeth W
EW
Triche
Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway.
Geir W
GW
Jacobsen
Department of Public Health and General Practice, Faculty of Medicine, Norwegian University of Science and Technology, Trondheim, Norway; Department of Pediatrics, St. Olav's University Hospital, Trondheim, Norway.
Kari R
KR
Risnes
D000328:Adult; D015331:Cohort Studies; D005260:Female; D005492:Folic Acid / Q000627:therapeutic use*; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007236:Infant, Small for Gestational Age; D009765:Obesity / Q000453:epidemiology*; D016017:Odds Ratio; D011225:Pre-Eclampsia / Q000453:epidemiology*; D011247:Pregnancy; D011248:Pregnancy Complications / Q000453:epidemiology; D011261:Pregnancy Trimester, First; D047928:Premature Birth / Q000453:epidemiology*; D011446:Prospective Studies; D065840:Protective Factors; D012307:Risk Factors; D014803:Vitamin B Complex / Q000627:therapeutic use*; D055815:Young Adult
D014803:Vitamin B Complex; D005492:Folic Acid
Folic acid; Low birth weight; Preeclampsia; Preterm labor