title: Effects of 25OHD concentrations on chances of pregnancy and pregnancy outcomes: a cohort study in healthy Danish women.
abstract: OBJECTIVE
  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.
  
  
  METHODS
  A total of 153 healthy Caucasian women with pregnancy plans were followed with measurements performed before pregnancy, at pregnancy weeks 11±2, 22±1 and 35±2 as well as 15±7, 129±12 and 280±15 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 (n=3) had lower P-25OHD concentrations at measurements performed in the first trimester compared with women without a miscarriage (P=0.03). 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 (P=0.59). 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.
  
  
  CONCLUSIONS
  P-25OHD concentrations did not affect fertility or pregnancy outcomes, although low P-25OHD may be associated with an increased risk of late miscarriage.
authors.affiliation: Department of Internal Medicine and Endocrinology, THG, Aarhus University Hospital, Aarhus, Denmark. kristine.moller@ki.au.dk
authors.forename: U K
authors.initials: UK
authors.lastname: Møller
authors.forename: S
authors.initials: S
authors.lastname: Streym
authors.forename: L
authors.initials: L
authors.lastname: Heickendorff
authors.forename: L
authors.initials: L
authors.lastname: Mosekilde
authors.forename: L
authors.initials: L
authors.lastname: Rejnmark
mesh_terms: D000022:Abortion, Spontaneous / Q000097:blood*; D000328:Adult; D001034:Apgar Score; D001724:Birth Weight; D001827:Body Height; D001942:Breast Feeding; D016022:Case-Control Studies; D015331:Cohort Studies; D003718:Denmark; D005260:Female; D005298:Fertility; D005306:Fertilization; D047109:Fetal Development; D006257:Head; D006801:Humans; D007231:Infant, Newborn; D049590:Postpartum Period; D011247:Pregnancy; D011256:Pregnancy Outcome; D011264:Pregnancy Trimesters; D012306:Risk; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
chemical_list: D014807:Vitamin D; C104450:25-hydroxyvitamin D