Maternal thyroid function and the outcome of external cephalic version: a prospective cohort study

Area of Science:

• Obstetrics and Gynecology
• Endocrinology
• Perinatal Medicine

Background:

• External cephalic version (ECV) is a procedure to manually turn a breech fetus to a cephalic presentation.
• Maternal thyroid function is crucial for pregnancy outcomes.
• The relationship between maternal thyroid function and ECV success is not well-established.

Purpose of the Study:

• To investigate the association between maternal thyroid function and the success rate of external cephalic version (ECV).
• To identify maternal and fetal factors influencing ECV outcomes in breech presentations.

Main Methods:

• A prospective cohort study involving 141 women with singleton breech presentation at ≥ 35 weeks gestation.
• Maternal blood samples were collected pre-ECV to assess thyroid function.
• ECV success was determined by post-procedure ultrasound.

Main Results:

• The overall ECV success rate was 55% (77/141), with higher success in multiparous (85%) compared to nulliparous women (39%).
• Women with failed ECV attempts had significantly higher TSH concentrations than those with successful ECV (p < 0.001).
• Elevated TSH levels, nulliparity, frank breech presentation, and anterior placenta were independently associated with lower ECV success rates.

Conclusions:

• Elevated maternal thyroid-stimulating hormone (TSH) levels are a significant risk factor for ECV failure.
• Thyroid function should be considered when assessing the likelihood of successful ECV in breech presentations.