Periconceptional intake of vitamins and fetal death: a cohort study on multivitamins and folate.
BACKGROUND
Women planning to conceive are often advised to take multivitamins. Whether this affects the survival of the fetus is not known.


METHODS
We used data from 35 914 women in the Danish National Birth Cohort who at recruitment had reported the number of weeks of supplement use during a 12-week periconceptional period. A telephone interview provided information about maternal characteristics and data on fetal death came from registers. The associations between periconceptional multivitamin or folate-only use and early (<20 weeks) and late (≥20 weeks) fetal death were estimated by hazard ratios (HR) with 95% confidence intervals (CI). Follow-up started at 8 completed weeks of gestation, and comparisons were made with no supplement use at any time during the periconceptional period.


RESULTS
Any multivitamin use was associated with a small increased crude risk of fetal death [HR 1.12 (1.01-1.25)], which was restricted to early losses [HR 1.18 (1.05-1.33)] compared with late losses [HR 0.82 (0.62-1.10)]. Adjustment for maternal factors increased this excess risk further. Whereas regular users of multivitamins (4-6 weeks of 6) before conception had more early losses [HR 1.29 (1.12-1.48)], a decreased risk of late losses was indicated when use started after conception [HR 0.65 (0.39-1.09)]. Folate-only use was not associated with fetal death.


CONCLUSIONS
Multivitamin use was associated with a modest increased risk of early fetal death. For late fetal death, regular supplement use after conception may decrease risk, but numbers were small. Further studies on preconceptional multivitamin use are needed to guide public health recommendations.
University of Southern Denmark, Institute of Clinical Research, Research Unit of Gynaecology and Obstetrics, Odense, Denmark, Aarhus University, Department of Public Health, Section for Epidemiology, Aarhus, Denmark, University of Pittsburgh Graduate School of Public Health, Department of Epidemiology, Pittsburgh, PA, USA, University of Pittsburgh, Department of Obstetrics, Gynecology & Reproductive Sciences, Pittsburgh, PA, USA and Statens Serum Institut, Department of Epidemiology, Copenhagen S, Denmark.
Ellen A
EA
Nohr
Jorn
J
Olsen
Bodil H
BH
Bech
Lisa M
LM
Bodnar
Sjurdur F
SF
Olsen
Janet M
JM
Catov
D000328:Adult; D001719:Birth Certificates; D015992:Body Mass Index; D015331:Cohort Studies; D019587:Dietary Supplements; D005260:Female; D005313:Fetal Death; D047109:Fetal Development / Q000187:drug effects; D005492:Folic Acid / Q000008:administration & dosage*; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D016742:Preconception Care; D011247:Pregnancy; D012307:Risk Factors; D012959:Socioeconomic Factors; D014815:Vitamins / Q000008:administration & dosage*
D014815:Vitamins; D005492:Folic Acid
Multivitamins; cohort study; dietary supplements; fetal death; folic acid; spontaneous abortion; stillbirth