From the Guidelines
No, an impacted (obstructed) fetal head is not predictable.
Risk Factors and Prediction
- The risk factors for an impacted fetal head are not well-established, and most studies have used second-stage cesarean delivery (CD) as a surrogate, making it challenging to separate the risks related to impacted fetal head from the general risks 1.
- According to a 2024 study published in the American Journal of Obstetrics and Gynecology, it is not possible to reliably predict an impacted fetal head, and obstetricians should be prepared to encounter this situation at any emergency CD 1.
- As a result, vigilance is crucial in these circumstances to ensure appropriate management and minimize potential complications.
- The study by Cornthwaite et al. in 2024 emphasizes the importance of being prepared for an impacted fetal head at any emergency CD, highlighting the unpredictability of this situation 1.
From the Research
Predictability of Impacted Fetal Head
- The predictability of an impacted fetal head is a complex issue, with various studies suggesting that it can be anticipated to some extent based on certain risk factors 2, 3, 4.
- Risk factors for impacted fetal head include advanced cervical dilatation, second stage of labor, oxytocin augmentation, fetal malposition, and junior grade of operating obstetrician 2, 3, 4.
- The incidence of impacted fetal head varies widely, ranging from 1.5% to 71.8% in emergency cesarean deliveries, depending on the definition and criteria used 2, 3, 4.
Identification of Risk Factors
- Advanced cervical dilatation is a significant risk factor for impacted fetal head, with studies showing that it is more common at cervical dilatation ≥8 cm 4.
- Labor augmentation with oxytocin and prolonged second stage of labor are also associated with an increased risk of impacted fetal head 2, 3.
- Fetal malposition and junior grade of operating obstetrician are additional risk factors that can contribute to the development of an impacted fetal head 2, 3.
Management and Prevention
- Various techniques and maneuvers have been proposed for the management of impacted fetal head, including the "push" technique, reverse breech technique, and the use of inflatable devices such as the Fetal Pillow 5, 6.
- An algorithm for management, such as the "ALERT" algorithm, can be useful in guiding clinical decision-making and reducing complications 6.
- Limiting uterine extensions and the push-method are also recommended as part of a prophylactic approach to prevent impacted fetal head 5.