Vitamin D metabolic profiling across pregnancy
Endocrine Abstracts (2015) 38 P362 | DOI:10.1530/endoabs.38.P362
Radhika Susarla1, Carl Jenkinson1, Jennifer Tamblyn1, Brian Keevil2, Shiao-Yng Chan1, Mark Kilby1 & Martin Hewison1
Presented at Conference in Edinburgh, UK, November 2015, Society for Endocrinology, British Endocrine Societies
Table 1 (rounded)
| 25(OH)D3 =VitD(nM) | Epi-25(OH)D3 (nM) | lα,25(OH)2D3 (pM) | 24,25(OH)D3 (nM) | DBP (μm) | Albumin (μm) | |
| Non-pregnant | 35 | 5 | 42 | 4.7 | 1.7 | 557 |
| 1st trimester | 35 | 8 | 52 | 2.8 | 2.3 | 554 |
| 3rd Trimester | 45 | 8 | 108 | 11 | 2.5 | 330 |
| Pre-eclampsia | 38 | 9.5 | 78 | 16 | 2.4 | 409 |
Vitamin D-deficiency during pregnancy has been associated with increased complications of pregnancy including a high risk of pre-eclampsia (PET). Current analysis of vitamin D ‘status’ is based exclusively on analysis of maternal serum 25-hydroxyvitamin D3 (25(OH)D3), the circulating precursor form of vitamin D. We hypothesised that comprehensive profiling of vitamin D metabolites may provide a more accurate determination of vitamin D function in pregnancy. A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to separate multiple vitamin D metabolites from serum samples obtained from: normal pregnant women (NP) at 1st trimester (n=22) and 3rd trimester (n=21); women with PET (n=21); non-pregnant female controls (n=20). Data (see table, Mean±S.E.M.) demonstrated that active (1α,25(OH)2D3, P<0.001), catabolic (24,25(OH)2D3, P<0.05) and inactive (Epi-25(OH)D3, P<0.01) are increased in serum from 3rd trimester and PET pregnancies relative to NP women. Epi-25(OH)D3 was elevated in all women across trimesters (P<0.01). By contrast, conventionally measured 25(OH)D3 showed no significant change in any of the groups. Ratio of 24,25(OH)2D3/1α,25(OH)2D3 was 100.8±2 in normal 3rd trimester, and 258.9±39 in PET (P<0.05). Ratio of Epi-25(OH)D3/1α,25(OH)2D3 was 77.4±7 in normal 3rd trimester, and 172.3±29 in PET (P<0.01). These data, suggests a shift towards catabolic pathway of vitamin D metabolism in PET. The albumin (decreases) and DBP (increases) levels inversely correlated with gestation (Table 1).
Measurement of multiple vitamin D metabolites and metabolites ratios may improve the interpretation of vitamin D status in pregnancy, possibly as an additional marker of adverse pregnancy events such as PET.