Is part of routine obstetric care to attempt a manual rotation in all fetus that are in a persistent OP at delivery. Nevertheless, little is known about the success of this intervention or about the relation of some ultrasound measures with the outcome.

Persistent OP at delivery occurs in approximately 10% of fetuses and studies have shown an increase in short-term and long-term maternal and fetal complications such as prolonged labour, maternal exhaustion, fetal distress, instrumental delivery, caesarean delivery and severe perineal tears. Manual rotation of the fetal occiput to OA position has been described as a safe and effective intervention in the setting of labour arrest but evidence is limited. Therefore, the investigators aim to evaluate:

1. The success of manual rotation of the fetal occiput in OP in 2nd stage of labour; The relation of progression angle (PA) accessed by ultrasound and the success of manual rotation; This is as prospective study with a sample size calculated of 50 participants.

1. º Identify an OP position during digital examination in the first evaluation at full cervical dilatation (t=0)
2. º Get informed consent from the pregnant woman.
3. º Wait for the first urge to push or T=30 m (multiparous) or T=60 (nulliparous)
4. º Confirm fetal head position by ultrasound and measure PA.
5. º Attempt a manual rotation to anterior position accordingly to the protocol.
6. º Confirm fetal head position by ultrasound.

Inclusion Criteria:

• Singleton pregnancies
• >37 weeks of pregnancy
• Fetus in cephalic presentation
• Fetal weight estimation P10-90
• Fetal head in a posterior position in the moment of full cervical dilatation.

Exclusion Criteria:

- do not give or do not be able to give written consent

pregnant women

All pregnant women in the delivery room that fulfill the inclusion criteria