[Ultrasonic convex array probe applied to increase success rate of external cephalic version without anesthesia]

Objective: To explore the feasibility of using ultrasonic convex array probe compressing abdominal wall to increase success rate of external cephalic version (ECV) without anesthesia in full-term and near-term pregnancy. Methods: Totally 190 singleton and non-cephalic presentation pregnant women in 36-39⁺⁴ weeks of gestation performed ECV from April 2019 to August 2023 in the First Affiliated Hospital of Nanjing Medical University were analyzed. According to whether use the ultrasound probe compressing fetal breech or not, the pregnant women were divided into two groups: 81 cases in the probe-compressing group (including primipara 61 cases and multipara 20 cases) and 109 cases in the non-probe-compressing group(including primipara 72 cases and multipara 37 cases). Clinical data, ECV related factors and complications were analyzed and compared between the two groups. Results: (1) The overall success rate of ECV was 64.2% (122/190). There was no significant difference in the success rate of ECV between probe-compressing group and non-probe-compressing group [69.1% (56/81) vs 60.6% (66/109), χ²=1.490, P=0.222]. The total vaginal delivery rate after successful ECV was 81.1% (99/122), while 71.1% (54/76) in primipara and 97.8% (45/46) in multipara, respectively. (2) Compare to the non-probe-compressing group, the success rate of ECV in primipara was significantly higher in the probe-compressing group [45.8% (33/72) vs 70.5% (43/61)], but the gestational age was shorter and the height was higher in the probe-compressing group (all P<0.05). The success rate of ECV of multipara in the probe-compressing group (65.0%, 13/20) was lower than that in the non-probe-compressing group (89.2%, 33/37), but there was no significant difference between the two groups (P>0.05). (3) Multivariate logistic regression analysis showed that abdominal wall compressed by ultrasound probe (OR=2.601, 95%CI: 1.113-6.075; P=0.027) and amniotic fluid index (AFI; OR=1.010, 95%CI: 1.001-1.020; P=0.028) were positive factors for the successful rate of ECV in primipara pregnant women. (4) The main complication of ECV was transient fetal heart rate reduction (8.9%,17/190), the incidence in the probe-compressing group was significantly higher than that in the non-probe-compressing group [14.8% (12/81) vs 4.6% (5/109); χ²=5.967, P=0.015]. No statistical differences were found in rates of complications between the ECV successful and unsuccessful pregnant women, and between probe-compressing and non-probe-compressing groups (all P>0.05). No adverse maternal and neonatal outcomes related to ECV were observed. Conclusions: The ultrasonic convex array probe compressing could significantly improve the success rate of ECV in primipara without increasing the incidence of adverse maternal and fetal outcomes. The success rate of ECV in primipara is influenced by AFI and operation mode.