Iodine monitoring models contribute to avoid adverse birth outcomes related more than adequate iodine intake.

BACKGROUND: Iodine plays an important role in pregnancy. How to maintain adequate iodine intake amongst pregnant women in each trimester of pregnancy to prevent adverse birth outcomes in central China is a challenge for clinical practice. METHODS: 870 pregnant women and their infants were enrolled in the study. Urinary iodine concentration (UIC) was measured using an inductively coupled plasma mass spectrometry (ICP-MS). Maternal and newborn information were obtained during follow-up. Multinomial logistic regression models were established. RESULTS: Median UIC of pregnant women was 172 ± 135 µg/L which is currently considered to be sufficient. Multivitamin supplements containing iodine, iodized salt intake and frequent milk intake were significantly associated with higher UIC. Multivariate logistic regression analysis showed that multivitamin supplements containing iodine and milk consumption were risk factors for more than adequate iodine (UIC ≥ 250 µg/L). Iodine-rich diet was significantly related to heavier birthweight, larger head circumference and longer femur length of the newborns while more than adequate iodine intake (UIC ≥ 250 µg/L) was a risk factor for macrosomia. Logistic regression models based on potential risk factors involving iodine containing supplements and iodine-rich diet were established to predict and screen pregnant women with high risk of more than adequate iodine intake among local pregnant women in different trimesters and guide them to supplement iodine reasonably to prevent the risk. CONCLUSIONS: Multivitamin supplements containing iodine and milk consumption were risk factors for maternal UIC ≥ 250 µg/L which was a risk factor for macrosomia. Iodine monitoring models were established to provide guidance for pregnant women to reduce the risk of more than adequate iodine intake, thereby contributing to reduce the risk of having a macrosomia.

Association between variants in vitamin D-binding protein gene and vitamin D deficiency among pregnant women in china.

BACKGROUND: The prevalence of vitamin D deficiency and insufficiency is extremely high in pregnant women worldwide. However, the association between single nucleotide polymorphisms (SNPs) in vitamin D metabolic pathway genes and 25-hydroxyvitamin D (25(OH)D) concentration among Chinese pregnant women is seldom reported. The risk of adverse neonatal outcomes due to maternal vitamin D deficiency has not been well investigated. METHODS: A total of 815 pregnant women and 407 infants were enrolled in this study. Serum 25(OH)D concentration was detected. DNA was extracted from the maternal blood for genotyping genetic SNPs in vitamin D pathway. An XGBoost model was established based on SNPs combined with external variables. RESULTS: Mean serum 25(OH)D level was 15.67 ± 7.98 ng/mL among the pregnant women. Seventy-five percent of pregnant women had 25(OH)D deficiency in China. SNPs of GC (rs17467825, rs4588, rs2282679, rs2298850, and rs1155563) were significantly associated with maternal 25(OH)D concentration. The influence of variants of rs17467825, rs4588, rs2282679, and rs2298850 on maternal 25(OH)D might be modified by vitamin D supplementation and sunshine exposure. An XGBoost model was established for monitoring 25(OH)D status in pregnant women and provided clinical advice to reduce the risk of 25(OH)D deficiency. Mothers with 25(OH)D deficiency hinted a risk for macrosomia. CONCLUSION: A high prevalence of vitamin D deficiency in China has been confirmed. A clinical model was established to guide pregnant women to supplement vitamin D according to genotype. Furthermore, we suggest the effect of maternal vitamin D status on the risk of macrosomia.