Systematic review and meta-analysis on the influence of thyroid dysfunction in early pregnancy on pregnancy outcomes under ultrasound guidance.

BACKGROUND

Thyroid dysfunction during pregnancy has a certain impact on pregnancy outcomes and neonatal growth, but there is no systematic evaluation of the influence of thyroid dysfunction during early pregnancy under ultrasound guidance on pregnancy outcomes.

METHODS

PubMed, Web of Science, Springer, and Science Direct databases were used to screen clinical studies on the effect of thyroid dysfunction during pregnancy on pregnancy outcomes from January 2010 to June 2021. Meta-analysis of data was conducted using RevMan 5.3 software. Differences of indicators were compared between the normal and abnormal thyroid function groups, including the ratio of primiparas, anemia, intrauterine growth restriction, perinatal fetal death, preterm delivery, fetal distress syndrome, cesarean section, preeclampsia, placental abruption, postpartum hemorrhage, and neonatal complications. Heterogeneity of results was assessed by chi-square test and I2 test in RevMan5.3.

RESULTS

A total of 788,867 pregnant women were included in 13 studies. Cochrane scores were grade B or above, and Jadad scale scores were higher than 3. Anemia [odds ratio (OR) =0.82, 95% confidence interval (CI): 0.70-0.96, Z=2.48, P=0.01], premature birth (OR =0.56, 95% CI: 0.36-0.86, Z=2.66, P=0.008), fetal distress syndrome (OR =0.76, 95% CI: 0.68-0.85, Z=4.74, P<0.00001), Apgar score <7 (OR =0.52, 95% CI: 0.34-0.80, Z=2.97, P=0.003), preeclampsia (OR =0.65, 95% CI: 0.48-0.87, Z=2.91, P=0.004), placental abruption (OR =0.27, 95% CI: 0.19-0.38, Z=7.31, P<0.00001), and the rate of postpartum hemorrhage (OR =0.62, 95% CI: 0.42-0.92, Z=2.38, P=0.02) were dramatically higher in the abnormal thyroid function group compared with the normal group.

DISCUSSION: Few studies were included on the effect of thyroid dysfunction on abortion, and further validation is needed. Thyroid dysfunction was proven to be associated with a variety of adverse pregnancy outcomes.