Effect of external cephalic version at term on fetal circulation

Area of Science:

• Perinatal medicine
• Fetal physiology
• Obstetric ultrasound

Background:

• External cephalic version (ECV) is a procedure to turn breech fetuses.
• The subclinical effects of ECV on fetal circulation require further investigation.
• Doppler ultrasonography provides non-invasive assessment of fetal and placental blood flow.

Purpose of the Study:

• To investigate the subclinical impact of external cephalic version (ECV) on fetal circulatory parameters.
• To assess changes in umbilical artery and fetal middle cerebral artery pulsatility indices before and after ECV.

Main Methods:

• A prospective observational study involving 136 fetuses undergoing ECV at or beyond 36 weeks gestation.
• Doppler ultrasonography was used to measure pulsatility indices of the umbilical artery and fetal middle cerebral artery pre- and post-ECV.
• Statistical analysis was performed using the Wilcoxon signed rank test.

Main Results:

• No significant changes were observed in the umbilical artery pulsatility index post-ECV.
• A statistically significant reduction in the fetal middle cerebral artery pulsatility index was noted after ECV (P =.043).
• This reduction was more pronounced in multiparous women, after difficult ECV procedures, or with a posterior placenta, but all values remained within normal limits.

Conclusions:

• External cephalic version does not appear to significantly disrupt placental circulation.
• ECV is associated with a transient reduction in fetal middle cerebral artery pulsatility, likely a normal physiological response to the procedure.
• The observed changes in fetal circulation post-ECV are not linked to procedural success or complications.