Delivery Mode and Neonatal Thyrotropin Levels: Insights From a Systematic Review and Meta-Analysis.

BACKGROUND

Optimal thyroid function is particularly crucial during infancy. This systematic review and meta-analysis aimed to investigate the relationship between the mode of delivery and neonatal thyrotropin levels at birth.

METHODS

We conducted a systematic search of MEDLINE/PubMed, Web of Science, Embase, Scopus, and the Cochrane Library for studies published up to 2023. Hedges' g with 95% confidence intervals was calculated to compare mean thyroid-stimulating hormone (TSH) levels based on the mode of delivery. Additionally, TSH levels were compared based on blood sampling methods, heel blood vs cord blood, using the same meta-analytic approach. A random effects model was employed due to the presence of heterogeneity. This study is registered with PROSPERO under the number CRD42024533649.

RESULTS

A total of 1438 studies were identified, of which 18 met the criteria for the systematic review. The meta-analysis of ten studies revealed significantly higher pooled TSH levels in neonates born via vaginal delivery compared to those delivered by cesarean section (Hedges' g = 0.390; P = .002). In the heel blood subgroup, no significant difference in TSH levels was found between vaginal and cesarean deliveries (Hedges' g = 0.167; P = .111). However, in the cord blood subgroup, neonates delivered vaginally exhibited significantly higher TSH levels than those delivered by cesarean section (Hedges' g = 0.493; P = .002).

CONCLUSION

The study found that the method of delivery has a significant impact on neonatal TSH levels, especially in umbilical cord blood samples, highlighting the need to consider delivery mode in evaluating neonatal health.