Association Between Maternal Subclinical Hypothyroidism and Growth Discordance in Twin Gestations: A Retrospective Study.

Purpose: It is reported that there is a growth discordance of at least 20% in about 16% of twin gestations, which may be associated with maternal, fetal, or placental factors. This study was performed to investigate the relationship between maternal subclinical hypothyroidism (SCH) and growth discordance in twin gestations. Patients and Methods: In this retrospective study, the clinical data of 106 women with twin gestations and their neonates were collected. The effect of maternal SCH on the growth discordance in twin gestations was analyzed using both linear and Logistic regression models. Results: Among the 106 women enrolled in our study, 48 cases (45.28%) were diagnosed with SCH, and 46 twins (43.40%) experienced growth discordance. Compared with those with smaller weight, the neonates with larger weight had a higher proportion of males (p<0.001), larger birth weight (p<0.001), birth height (p=0.009) and birth head circumference (p=0.001). Women with SCH showed a higher proportion of growth discordance (p=0.005) and larger difference in the body weight (p=0.021). Logistic regression analysis showed that maternal SCH was an independent risk factor for birth weight discordance in twins (95% CI: 1.601-9.425, p=0.003). Linear analysis further revealed that maternal SCH was positively associated with the birth weight difference in twins (95% CI: 0.261-8.308, p=0.037). Conclusion: Our findings suggest that maternal SCH may serve as an independent risk factor for birth weight discordance and is positively associated with the birth weight difference in twins.