English abstract
Spontaneous abortion affects up to one in five women who conceive and may be associated with thyroid autoimmunity (TAI). Vitamin D deficiency has been observed in several autoimmune diseases.
This study aimed to assess TAI and determine vitamin D status in pregnant Omani women who had spontaneous abortion of unknown etiology (within week 12) using as controls, non-aborted Omani pregnant women matched for gestation.
Manual ELISA techniques were used to measure serum total 25-OHD, anti thyroperoxidase (anti-TPO), and anti-thyroglobulin (anti-Tg). Parathyroid hormone (PTH), free thyroxine (FTA) and thyroid-stimulating hormone (TSH) were assayed by Beckman Coulter UniCel DxI 600 Access Immunoassay analyzer Serum alkaline phosphatase (ALP), calcium, magnesium, and phosphate were measured on Roche Cobas 111 analyser, Calcium adjusted for albumin effect was reported.
Presenting results as median (inter-quartile) values, 25(OH)D (nmol/L) in the aborted women of 36.3 was considerably lower (p=0.001) than 44.7 in the non-aborted. The median calcium (mmol/L) of 2.16 in aborted was significantly lower (P=0.001) than 2.27 in non-aborted. PTH median (pmol/L) of 2.8 in the aborted was higher (P=0.027) relative to 2.4 in non-aborted. 66.7% of the non-aborted, and 73.3% of the aborted were respectively, vitamin D insufficient at the 550 nmol/L recommended cut-off point. Mild association was observed between total 25(OH)D and age in the aborted (r=0.342; P=0.021). In the non-aborted, total 25(OH)D also mildly associated with total calcium (r=0.333; P=0.025), and phosphate (r=0.310; P=038) but inversely associated with FT4 (r=0.279; P=0.063). Although anti-TPO and anti-TG were elevated in the aborted group compared with the non-aborted, the levels were not considered abnormal.
There was greater prevalence in vitamin D insufficiency in spontaneously aborted compared with non-aborted but both groups had normocalcemia; thyroid autoimmunity was not indicated.
