Occiput posterior position and intrapartum sonography

The occiput posterior position is reported to be the most common of all malpositions, and it may present as either straight (OP), left (LOP), or right (ROP). Diagnosis of OP position can be made at different times: during the third trimester, prior to the onset of labor, during the first stage of labor, while the fetus is transiting in the birth canal, and at birth. The time of diagnosis, though, is of different clinical significance, moving or not to a very specific management. Manual diagnosis of occiput posterior position either with abdominal palpation or vaginal examination is very subjective, prone to mistake, operator dependent, and made more difficult by caput and molding. Intrapartum ultrasonography has become a very reliable tool to hell the clinician to make a true diagnosis of malposition. The ultrasound probe may be used with different approach: transabdominal, suprapubical, transperineal, and transvaginal. The correct diagnosis of fetal head position as occiput posterior is imperative to be obtained in the management of any dystocia that may occur in the different stages of labor. Its knowledge will help the clinician to make the right decision at the right time, with the ultimate goal to reduce maternal and neonatal morbidity.