From the Guidelines
Diagnosis of occiput posterior (OP) presentation during labor should involve a combination of clinical signs, vaginal examination, and ultrasound assessment to confirm fetal position, as it is associated with longer labors, increased risk of instrumental delivery, and higher cesarean section rates 1. The primary methods for diagnosing OP position include:
- Vaginal examination to palpate the fetal skull sutures and fontanelles, with the posterior fontanelle directed toward the mother's sacrum rather than her pubic bone
- Abdominal examination may reveal a flattened abdomen with fetal limbs palpable anteriorly and the fetal heart heard best in the maternal flank
- Ultrasound assessment during labor provides the most accurate confirmation of fetal position Common clinical indicators suggesting OP position include:
- Prolonged labor
- Intense back pain ("back labor")
- Irregular contractions
- Early urge to push
- Maternal exhaustion It is essential to identify OP position early, as it allows for appropriate interventions such as maternal positioning changes, movement encouragement, and manual rotation techniques if necessary, which can help reduce the risk of complications and improve outcomes 1. Healthcare providers should maintain a high index of suspicion for OP position when labor progress slows, especially in the first stage or during descent in the second stage, and consider evaluating for other factors that may be contributing to the labor abnormality, such as cephalopelvic disproportion, inhibitory factors, or fetal malposition 1.
From the Research
Diagnosis of Occiput Posterior Presentation
The diagnosis of occiput posterior (OP) presentation during labor can be made through various methods, including:
- Digital vaginal examination 2, 3
- Ultrasound scan, which is considered a reliable way to detect fetal position 2, 3, 4
- Transabdominal ultrasonography, which can be used to determine presentation during labor 3
- Evaluation by simulation algorithm (ESA) approach, which uses intrapartum ultrasound to quantify the occiput posterior position of the fetal head in the pelvis and birth canal 4
Challenges in Diagnosis
The diagnosis of OP presentation is often made late, at the end of dilation, and can be associated with increased risk of complications, such as:
- Unusually long labor
- Maternal and fetal exhaustion
- Instrument-assisted delivery
- Severe perineal injury
- Cesarean section 3
Importance of Accurate Diagnosis
Accurate diagnosis of OP presentation is crucial to predict the success of labor management and to reduce the risk of interventions and complications. Ultrasound diagnosis of OP position during labor can predict OP position at birth, and knowledge of the exact position of the fetal head is essential prior to any operative vaginal delivery 4
Methods to Correct OP Position
Various methods have been proposed to correct OP position, including:
- Manual rotation of the fetal head to occiput anterior position, which has been shown to be effective in reducing the rate of instrumental fetal delivery and cesarean section 5
- Maternal positioning, such as the hands and knees position, which may increase comfort but has not been shown to facilitate rotation into occiput anterior position 6