Supplemental iodine-containing prenatal multivitamins use and the potential effects on pregnancy outcomes in a mildly iodine-deficient region
- 8 June 2020
- journal article
- research article
- Published by Springer Science and Business Media LLC in Journal of Endocrinological Investigation
- Vol. 44 (3), 443-452
- https://doi.org/10.1007/s40618-020-01321-6
Abstract
Purpose The use and contribution of prenatal multivitamins (PMV) as iodine source for pregnant women in China, especially in mildly iodine-deficient region, have not been well studied. This study aimed to explore the association between PMV intake during pregnancy and thyroid function in mothers and newborns. Methods We performed a study involving women with a history of taking PMV during pregnancy between January 2013 and October 2015, in Shanghai, a mildly iodine-deficient region. Maternal thyroid function in early and late pregnancy, and neonatal TSH on postnatal d 3 were obtained from medical records. We compared the outcomes in pregnant women who took exclusively iodine-containing PMV (I + PMV) with those who took exclusively non-contained PMV (I− PMV). Propensity score matching (PSM) was used to identify women with similar baseline characteristics. Results After PSM, 1280 women in I + PMV and 2560 in I- PMV had similar propensity scores and were included in the analyses. Introduction of I + PMV to women was associated with slightly higher maternal thyroid hormone production (higher maternal FT4, p = 0.01, non-significantly lower TSH, p = 0.79) and lower neonatal TSH levels (p < 0.0001). The frequency of adverse pregnancy outcomes or thyroid dysfunctions did not differ between groups in late pregnancy. Mothers received I + PMV (0.2 SD) had a stronger association of maternal TSH with neonatal TSH than those who received I- PMV (0.1 SD). These effects were only shown in TPOAb-negative mothers, not in TPOAb-positive mothers. Conclusion TPOAb-positive women display an impaired iodine transport in thyroid and placenta, and this may explain the lack of changes in maternal and neonatal thyroid parameters with I + PMV supplementation in these women. This phenomenon might suggest that these women require different iodine doses or treatment approach in comparison with TPOAb-negative women.Keywords
Funding Information
- the national key Research and Development Program of China (2018YFC1004602)
- CAMS Innovation Fund for Medical Sciences (2019-I2M-5-064)
- Shanghai Municipal Key Clinical Specialty
- Chinese Academy of Medical Sciences Research Unit, Shanghai Jiao Tong University (2019RU056)
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