title: Infant birth size is not associated with maternal intake and status of folate during the second trimester in Norwegian pregnant women.
abstract: Maternal folate status and smoking are potentially strong risk factors for infant birth size. We assessed the association of several folate indicators and smoking with birth outcomes in a subsample of participants in the Norwegian Mother and Child Cohort Study, consisting of 2934 singleton pregnancies in 2002-2003. Blood plasma folate and cotinine concentrations and self-reported intake of food folate and supplemental folic acid were measured during the second trimester (median 18 wk). Birth outcomes included gestational age, infant birth weight, head circumference, crown-heel length, and small for gestational age (SGA). Mean total dietary folate intake from foods (mean 268.0 microg/d) and supplements (mean 187.7 microg/d) was 455.7 microg/d. Smokers (plasma cotinine > or = 85 nmol/L) had substantially lower supplemental folic acid intake than nonsmokers, but they did not differ regarding folate intake from food only. Nevertheless, smoking was correlated with plasma folate both before and after adjusting for total dietary folate intake (both P < 0.001). We found no significant associations of food folate intake, supplemental folic acid use, total dietary folate intake, or plasma folate with the various birth outcomes after adjustment for potential confounders. Consistent with previous studies, infant birth size was strongly predicted by maternal smoking (adjusted odds ratio for SGA: 2.3; 95% CI: 1.6, 3.3). This study of well-nourished Norwegian pregnant women suggests that dietary folate and plasma folate during the second trimester are not risk factors for infant birth size.
authors.affiliation: Department of Public Health and Primary Health Care, University of Bergen, Bergen 5020, Norway. roy.nilsen@uib.no
authors.forename: Roy M
authors.initials: RM
authors.lastname: Nilsen
authors.forename: Stein Emil
authors.initials: SE
authors.lastname: Vollset
authors.forename: Anne Lise B
authors.initials: AL
authors.lastname: Monsen
authors.forename: Arve
authors.initials: A
authors.lastname: Ulvik
authors.forename: Margaretha
authors.initials: M
authors.lastname: Haugen
authors.forename: Helle Margrete
authors.initials: HM
authors.lastname: Meltzer
authors.forename: Per
authors.initials: P
authors.lastname: Magnus
authors.forename: Per Magne
authors.initials: PM
authors.lastname: Ueland
mesh_terms: D000293:Adolescent; D000328:Adult; D001724:Birth Weight / Q000187:drug effects*; D015930:Diet Records; D019587:Dietary Supplements; D005260:Female; D005492:Folic Acid / Q000008:administration & dosage* / Q000097:blood / Q000494:pharmacology*; D005504:Food Analysis; D006801:Humans; D007231:Infant, Newborn; D039382:Maternal Nutritional Physiological Phenomena; D009664:Norway; D011247:Pregnancy; D011262:Pregnancy Trimester, Second; D055815:Young Adult
chemical_list: D005492:Folic Acid