Effects of 25OHD concentrations on chances of pregnancy and pregnancy outcomes: A cohort study in healthy Danish women

Abstract

BACKGROUND/OBJECTIVES:Plasma 25-hydroxyvitamin D (P-25OHD) concentrations may affect pregnancy outcomes. To elucidate this further, we studied the effects of pre-conception P-25OHD concentrations on chances for pregnancy as well as the effects of P-25OHD during pregnancy on the risk of miscarriage, birth weight and length, Apgar score and head circumference. Moreover, we studied whether pregnancy and breastfeeding patterns affect maternal P-25OHD concentrations.SUBJECTS/METHODS:A total of 153 healthy Caucasian women with pregnancy plans were followed with measurements performed before pregnancy, at pregnancy weeks 112, 221 and 352 as well as 157, 12912 and 28015 days postpartum. Furthermore, 75 non-pregnant, age-matched women were followed in parallel as controls.RESULTS:The 203 women were aged 29 (25-35) years. At baseline, median P-25OHD was 59 nmol/l. Of these women, 31% had P-25OHD 50 nmol/l, whereas 12% had levels above 80 nmol/l. Within 6 months after inclusion, 63% conceived. P-25OHD was not associated with chances of conceiving or overall risk of miscarriage. However, women with a miscarriage in their second trimester (n3) had lower P-25OHD concentrations at measurements performed in the first trimester compared with women without a miscarriage (P0.03). P-25OHD before or during pregnancy was not associated with gestational length or infant parameters. Adjustments for possible confounders did not change the result. During pregnancy, P-25OHD changed significant over time, but similar changes occurred within the control group, indicating no effect of pregnancy per se (P0.59). Overall, P-25OHD did not differ according to length of breastfeeding at 2 weeks, and 4 and 9 months postpartum, although women breastfeeding for 9 months had lower P-25OHD levels at the last visit compared with the controls.CONCLUSION:P-25OHD concentrations did not affect fertility or pregnancy outcomes, although low P-25OHD may be associated with an increased risk of late miscarriage. © 2012 Macmillan Publishers Limited.