Management of impacted fetal head at cesarean delivery

Globally, more than 1 in 5 women give birth by cesarean delivery, and at least 5% of these births are at full cervical dilatation. In these circumstances, and when labor has been prolonged in the first stage of labor, the fetal head can become low and wedged deep in the woman's pelvis, making it difficult to deliver the baby. This emergency is known as impacted fetal head. These are technically challenging births associated with serious risks to both the woman and the baby. The difficulty in disimpacting the fetal head increases maternal risks of hemorrhage and injury to adjacent organs and may have long-term consequences for future pregnancies. In addition, there can be associated neonatal consequences, such as skull fractures, brain hemorrhage, hypoxic brain injury, and, rarely, perinatal death. Globally, maternity staff are increasingly encountering this emergency, with studies in the United Kingdom suggesting that impacted fetal head may complicate as many as 1 in 10 emergency cesarean deliveries. Moreover, there has been a sharp increase in reports of perinatal brain injuries associated with impaction of the fetal head at cesarean delivery. When an impacted fetal head occurs, the maternity team can employ a range of approaches to help deliver the fetal head, including an assistant (another obstetrician or midwife) pushing the head up from the vagina, delivering the baby feet first (reverse breech extraction), administering tocolysis to relax the uterus, and using a balloon cephalic elevation device (Fetal Pillow) to elevate the baby's head. However, there is currently no consensus on how best to manage these births, resulting in a lack of confidence among maternity staff, variable practice, and potentially avoidable harm in some circumstances. This article examined the evidence for the prevention and management of this critical obstetrical emergency and outlined recommendations for best practices and training.

Management of Impacted Fetal Head at Caesarean Birth: Scientific Impact Paper No. 73

Over one-quarter of women in the UK have a caesarean birth (CB). More than one in 20 of these births occurs near the end of labour, when the cervix is fully dilated (second stage). In these circumstances, and when labour has been prolonged, the baby's head can become lodged deep in the maternal pelvis making it challenging to deliver the baby. During the caesarean birth, difficulty in delivery of the baby's head may result - this emergency is known as impacted fetal head (IFH). These are technically challenging births that pose significant risks to both the woman and baby. Complications for the woman include tears in the womb, serious bleeding and longer hospital stay. Babies are at increased risk of injury including damage to the head and face, lack of oxygen to the brain, nerve damage, and in rare cases, the baby may die from these complications. Maternity staff are increasingly encountering IFH at CB, and reports of associated injuries have risen dramatically in recent years. The latest UK studies suggest that IFH may complicate as many as one in 10 unplanned CBs (1.5% of all births) and that two in 100 babies affected by IFH die or are seriously injured. Moreover, there has been a sharp increase in reports of babies having brain injuries when their birth was complicated by IFH. When an IFH occurs, the maternity team can use different approaches to help deliver the baby's head at CB. These include: an assistant (another obstetrician or midwife) pushing the head up from the vagina; delivering the baby feet first; using a specially designed inflatable balloon device to elevate the baby's head and/or giving the mother a medicine to relax the womb. However, there is currently no consensus for how best to manage these births. This has resulted in a lack of confidence among maternity staff, variable practice and potentially avoidable harm in some circumstances. This paper reviews the current evidence regarding the prediction, prevention and management of IFH at CB, integrating findings from a systematic review commissioned from the National Guideline Alliance.

Risks associated with cesarean delivery during prolonged second stage of labor

BACKGROUND

Data regarding maternal and fetal morbidities are limited to surgical morbidity per each additional hour in the second stage of labor.

OBJECTIVE

This study aimed to quantify perinatal morbidities associated with cesarean delivery by duration of the second stage of labor.

STUDY DESIGN

Our work is a retrospective cohort study of cesarean deliveries during the second stage of labor using the Consortium on Safe Labor database. All term, singleton pregnancies in cephalic presentation were included. Women with stillbirth or contraindications to vaginal delivery were excluded. Groups were divided by duration of the second stage of labor: ≤3 hours, 3-4 hours, 4-5 hours, 5-6 hours, and >6 hours. The primary outcome was a composite of maternal morbidities. The secondary outcomes were a composite of neonatal morbidities and individual maternal and neonatal morbidities. Baseline demographic and clinical characteristics were compared among groups. Univariate and multivariate analyses were performed.

RESULTS

We included 6273 women in total. In addition, 3652 women (58.2%) went through the second stage for ≤3 hours, 854 (13.6%) for 3 to 4 hours, 618 (9.9%) for 4 to 5 hours, 397 (6.3%) for 5 to 6 hours, and 752 (12.0%) for >6 hours. Neither the maternal nor neonatal morbidity composite outcomes were statistically different among the groups. Extended maternal length of stay (>5 days), increased birthweight, and lower rates of general anesthesia were associated with an increased duration of the second stage of labor. Chorioamnionitis, wound complications, postpartum hemorrhage, and thrombosis did not increase over time.

CONCLUSION

Women should be counseled regarding the duration of the second stage of labor, which should include a discussion of the risks associated with a cesarean delivery with a prolonged second stage of labor. However, these risks may not be as high as anticipated.

Prediction of successful trial of labor after cesarean - the benefit of prior vaginal delivery

OBJECTIVE

To determine predictive factors for vaginal birth after cesarean section (VBAC).

METHODS

A retrospective cohort study of all women with singleton pregnancies and a prior single low transverse cesarean section (CS) who attempted vaginal delivery in a tertiary hospital (2010-2014). Pregnancy outcome of women with VBAC was compared to those who failed vaginal delivery. Sub-analysis for women with no prior vaginal deliveries was performed. Pregnancies with non-cephalic presentation, estimated fetal weight >4000 g and any contraindications for vaginal delivery were excluded.

RESULTS

Of the 40 714 deliveries, 1767 women met inclusion criteria. Among them 1563 (88.5%) had a VBAC and 204 (11.5%) failed. There was no significant difference between the groups regarding maternal age, comorbidities and pregnancy complications. Predictors for VBAC were (odds ratio, 95% confidence interval) interval from prior CS (1.13, 1.04-1.22, p=0.004), previous VBAC (2.77, 1.60-4.78, p < 0.001), prior vaginal delivery prior to the CS (3.05, 1.73-5.39, p < 0.001) and induction of labor (0.62, 0.40-0.97, p = 0.03). For women with no prior vaginal birth, only birthweight was associated with VBAC (0.99, 0.99-1.00, p = 0.02).

CONCLUSION

While different variables may influence the rate of VBAC, the predictive ability of VBAC for women with no previous vaginal deliveries remains poor.