Vitamin D status in mothers with pre-eclampsia and their infants: a case-control study from Serbia, a country without a vitamin D fortification policy

Abstract

Objective: The objective of the present study was to determine if vitamin D intake and status are associated with pre-eclampsia in a country without a vitamin D fortification policy.

Design: A case-control study of pregnancies with (case) and without (control) pre-eclampsia was conducted from January to April when UVB is minimal. Maternal and cord blood obtained at delivery were measured for plasma 25-hydroxycholecalciferol (25-OH-D3), 3-epimer of 25-OH-D3 (3-epi-25-OH-D3) and 24,25-dihydroxycholecalciferol (24,25-(OH)2D3) by LC-MS/MS and maternal 1,25-dihydroxyvitamin D (1,25-(OH)2D). Differences between groups were tested with ANOVA and Bonferroni post hoc tests (P<0·05).

Setting: Clinical Center of Serbia.

Subjects: Pregnant women with and without pre-eclampsia (n 60) and their infants.

Results: Exogenous vitamin D intake (0·95-16·25 µg/d (38-650 IU/d)) was not significantly different between groups. Women with pre-eclampsia delivered infants at an earlier gestational age and had significantly lower mean total plasma 25-hydroxyvitamin D (25-OH-D; case: 11·2 (sd 5·1); control: 16·1 (sd 5·7) ng/ml; P=0·0006), 25-OH-D3 (case: 10·0 (sd 4·9); control: 14·2 (sd 5·8) ng/ml; P=0·002), 3-epi-25-OH-D3 (case: 0·5 (sd 0·2); control: 0·7 (sd 0·2) ng/ml; P=0·0007) and 1,25-(OH)2D (case: 56·5 (sd 26·6); control: 81·0 (sd 25·7) pg/ml; P=0·018), while 24,25-(OH)2D3 was not different between groups. Infants did not differ in total plasma 25-OH-D, 25-OH-D3, 3-epi-25-OH-D3 and 24,25-(OH)2D3, but the mean proportion of 3-epi-25-OH-D3 was higher in the infant case group (case: 7·9 (sd 1·1); control: 7·0 (sd 1·4) % of total 25-OH-D3; P=0·005).

Conclusions: A high prevalence of vitamin D deficiency, as defined by plasma 25-OH-D<12 ng/ml, was observed in 47 % of all mothers and 77 % of all infants. These data underscore the need for prenatal vitamin D supplementation and a food fortification policy in Serbia.

Keywords: C3-epi-25-hydroxycholecalciferol; LC–MS/MS; Maternal and cord blood; Pre-clampsia; Pregnancy; Vitamin D status.

Fig. 1

Vitamin D status of mothers in the case (with pre-eclampsia; n 30) and control group (without pre-eclampsia; n 30), Serbia, January–April 2011: (a) 25-hydroxycholecalciferol (25-OH-D₃); (b) total 25-hydroxyvitamin D (25-OH-D); (c) 3-epimer of 25-hydroxycholecalciferol (3-epi-25-OH-D₃); and (d) 25-hydroxyergocalciferol (25-OH-D₂). ———, 20 ng/ml target to support bone health; – – – – –, below 12 ng/ml is consistent with deficiency; · · · · ·, below 10 ng/ml is consistent with severe deficiency. Results are presented as scatter plots with mean and sd. Differences between groups tested with the Mann–Whitney test: (a) P=0·002; (b) P=0·0006; (c) P=0·0007; and (d) P<0·0001

Fig. 2

Vitamin D status of infants in the case (mothers with pre-eclampsia; n 23) and control group (mothers without pre-eclampsia; n 26), Serbia, January–April 2011: (a) 25-hydroxycholecalciferol (25-OH-D₃); (b) total 25-hydroxyvitamin D (25-OH-D); (c) 3-epimer of 25-hydroxycholecalciferol (3-epi-25-OH-D₃); and (d) 25-hydroxyergocalciferol (25-OH-D₂). ———, 20 ng/ml target to support bone health; – – – – –, below 12 ng/ml is consistent with deficiency; · · · · ·, below 10 ng/ml is consistent with severe deficiency. Results are presented as scatter plots with mean and sd. Differences between groups tested with the Mann–Whitney test: (a) P=0·0627; (b) P=0·0571; (c) P=0·4122; and (d) P=0·6963