Authors

1Cristina Molina Reyes, 2Antonio Luis Muñoz Martínez

Position

¹Matrona. Unidad de Partos del Hospital General Básico de Baza, Granada.²Matrón. Unidad de Partos del Hospital de San Juan de la Cruz, Jaén.

Contact address

Unidad de Partos. Hospital General Básico de Baza. Carretera de Murcia, s/n. 18800 Baza, Granada.

Contact email: cristimolina66@hotmail.com

Abstract

Objective: bibliographic review on occipito-posterior foetal position, with the aim of acquiring updated knowledge from the scientific community concerning OP foetal position.
Material and method: bibliographic review performed during the month of january 2009, analyzing clinical trials, case-control prospective studies, retrospective studies and case studies, as well as bibliographic reviews on the OP foetal position, factors which influence its incidence, diagnostic methods, associated complications, and interventions that are employed to correct it or improve maternal-foetal outcomes.  The key words used in the search have been occipito-posterior and occipitoposterior.  The following databases have been consulted: PubMed, CUIDEN, SCIELO, LILACS and Academic GOOGLE.  
Results: the incidence of this position is 15-40% at the onset of labour.     In most cases the foetus rotates spontaneously to an occipito-anterior position, but in 1,8-6% of cases the occipito-posterior position persists.  It is related with maternal pelvic anomalies, nulliparity, prior C-sections, recurrence in following labours, posterior placental implantation, prolonged pregnancy, administration of epidural analgesia and oxytocin, foetal weight and abnormal foetal axis.  For its diagnosis ultrasound is more accurate than manual exploration, even though the latter may be more reliable in labour units without ultrasound equipment.  This position increases the duration of the first and second phases of labour, persistent back pain, instrumental labour, C-sections, episiotomies, perianal and anal sphincter lesions, as well as lower score neonatal assessments at birth.  In order to correct this foetal position, instrumental rotation is employed using forceps and vacuum extraction, manual rotation and manual correction of the foetal axis, as well modification of the maternal posture.   
Conclusions: an early and correct diagnosis of this position should be performed, and an attempt should be made to correct it using effective and non-invasive techniques.  Modification of the maternal posture during labour may be an effective intervention, even though more studies are needed to confirm it.   

Keywords:

occipito-posterior; occipito-anteriorfoetal malposition

Versión en Español

Título:

La malposición fetal occipito-posterior. Revisión bibliográfica