NEW YORK (Reuters Health) – Delivery of the neonate via emergency cesarean section occurs more quickly with a vertical skin incision than a transverse skin incision, but this is not associated with improved neonatal outcomes, a new study shows.

In fact, the researchers found some evidence of better neonatal outcomes as well as fewer maternal complications with the transverse skin incision.

However, first author Dr. Blair J. Wylie told Reuters Health by phone, “In my mind, I don’t think this is a practice changing paper.”

The literature comparing transverse with vertical skin incisions for cesarean delivery, particularly for emergent cases, is sparse. Therefore, Dr. Wylie, from Massachusetts General Hospital, Boston and colleagues compared incision-to-delivery time, total operative time, and maternal and neonatal outcomes by incision type in a large series of emergency c-sections.

Of a total of 37,112 live singleton cesarean deliveries at 13 US hospitals from 1999 to 2000, 3,525 (9.5%) were performed for emergency indications. Of these, 2,498 (70.9%) were performed by transverse incision and the remaining 1,027 (29.1%) by vertical incision.

Compared with transverse skin incision, vertical skin incision shortened the median incision-to-delivery interval by 1 minute in primary cesarean deliveries (3 compared to 4 minutes, p < 0.001) and by 2 minutes in repeat cesarean deliveries (3 compared to 5 minutes, p < 0.001), the investigators report.

“This research gives us the confidence that both (incision types) are very fast and obviously there is provider preference,” Dr. Wylie told Reuters Health.

“In certain emergent situations,” Dr. Wylie and colleagues note in their paper, “such as a cord prolapse without a detectable fetal heart rate or a profound bradycardia, the additional 1 to 2 minutes saved by a vertical skin incision could perhaps be significant.”

Despite shorter incision-to-delivery times with vertical incision, total median operative time was longer after vertical skin incision by 3 minutes in primary cesarean deliveries (46 vs 43 minutes, p < 0.001) and by 4 minutes in repeat deliveries (56 vs 52 minutes, p < 0.001).

The researchers also found that neonates delivered via vertical skin incision were more likely to be intubated in the delivery room (17% vs 13%, p = 0.001), to have an umbilical artery pH less than 7.0 (10% vs 7%, p = 0.02), or to be diagnosed with hypoxic ischemic encephalopathy (3% vs 1%, p < 0.001).

Immediate intraoperative and postoperative maternal complications were similar in the two groups, with the primary exception of an increase in postpartum transfusions with vertical incision for both primary cesarean deliveries (7% vs 5% for transverse incision, p = 0.01) and repeat cesarean deliveries (14% vs 8%, p = 0.02). These differences, the authors say, could be due, at least in part, to uncontrolled confounding factors rather than being a reflection of the type of skin incision.

There was also an increased incidence of postpartum endometriosis in women delivered by vertical skin incision (15% compared with 11%, p = 0.006), although the authors say they are unsure how incision location might affect this.

Dr. Wylie and his colleagues urge caution in interpreting these results. They point out that the study was observational, and the rationale for why a physician chose a particular incision type was unknown. “In repeat cesarean deliveries, for instance, we did not know the location of the prior skin incision and whether this influenced the current incision type.”

The degree of urgency with which emergency cesarean was performed is another potentially important unknown. “Our data may simply demonstrate that the sickest fetuses were delivered the quickest. Perhaps vertical incisions were chosen in the most urgent situations, biasing the results toward an apparent time advantage and an apparent neonatal disadvantage with this approach.”

References:
Obstet Gynecol 2010;115:1134-1140.