Preconceptional folate supplementation and the risk of spontaneous preterm birth: A cohort study

Radek Bukowski, Fergal D. Malone, Flint T. Porter, David A. Nyberg, Christine H. Comstock, Gary D.V. Hankins, Keith Eddleman, Susan J. Gross, Lorraine Dugoff, Sabrina D. Craigo, Ilan E. Timor-Tritsch, Stephen R. Carr, Honor M. Wolfe, Mary E. D'Alton