Ultrasound Parameters for the Outcome Prediction of External Cephalic Version for Fetuses with Breech Presentation

Pregnant women with a diagnosis of fetal breech presentation, desirous of an attempt of ECV after counseling and written consent and hospitalized for the procedure will be consecutively enrolled. The following anonymous data will be recorded:

• Demographic and anthropometric data (i.e., age (y), ethnicity, height (m), weight (kg), BMI);
• Parity
• Gestational Age (weeks + days)

Before ECV attempt, the following evaluations will be performed:

• Vaginal examination to evaluate the cervical dilatation and the level of presenting part (floating or not floating)
• Fetal transvaginal ultrasound reporting:

• biometry (BPD, HC, AC, FL, EFW);
• Occiput position (right, left);
• Back position (anterior, posterior, right, left);
• Breech variant (footling, frank, complete);
• Fetal leg posture (extended, flexed)
• Placental localization;
• Amniotic Fluid Index (AFI);
• Fore-bag of amniotic fluid;
• Eventual presence of nuchal cords;
• Fetal head ballottement (yes, no);
• Occiput-spine angle (see Figure 1)

Then, all the participants will undergo a transabdominal ultrasound-guided ECV in a semi-sitting position by the same expert operator (B.C.). After the procedure, the following data will be collected:

• Success (yes, no)
• Duration of the procedure (min);
• Direction of fetal flip in case of success (frontside flip, backside flip)
• Pain perception in Numerical Rating Scale (NRS) (1-10);
• Reason for terminating the procedure (success, failure, pain, uterine contractions, non-reassuring fetal conditions)

Inclusion criteria

• Age ≥18 y.o.;
• Pregnant women with a diagnosis of fetal breech presentation eligible and desirous for ECV;
• Singleton;
• At term (≥ 37 weeks);
• Breech presentation;
• No previous uterine scars or other indications for elective C-section;
• Signed written informed consent to study participation.

Exclusion criteria

• Age <18 y.o.;
• Preterm gestational age;
• Multiple pregnancies;
• Indications for elective cesarean section;
• Incomplete obstetrical data;
• Refusal to provide informed consent.
• Desire to an elective C-Section
• Controindications for ECV or vaginal delivery (placental abruption, placenta previa, uterine malformations)
• Reduction of amniotic fluid (AFI <4 cm)
• Uterine contractions
• Vaginal bleeding
• Premature rupture of membranes
• Nonreassuring fetal heart rate patterns before the procedure.