The Second Stage of Labor: How Long is Too Short?

What does labor look like on TV? The woman’s water always breaks at the mall or during an important meeting, followed by a quick pushing montage at the hospital, and ending with all of her best friends gathered around the hospital bed for the official naming ceremony.

Anyone who has actually seen or experienced labor knows this is far from reality. That quick pushing montage is usually preceded by hours of contractions while the cervix slowly dilates. And that five-minute pushing/screaming/cursing the husband scene? Known as the “second stage” of labor, it usually lasts a lot longer than five minutes. In fact, a prolonged second stage of labor is defined as longer than three hours with an epidural or longer than two hours without an epidural, for first time moms. If after two or three hours, a woman is still pushing, standard medical recommendations call for “expedited delivery”- either a cesarean delivery or an operative vaginal delivery (forceps or a vacuum).

However, the United States has seen an ever-increasing percentage of births by cesarean section. Obstetricians strive to decrease the cesarean section rate while still protecting mothers and infants from complications. This month Dr. Gimovsky and Dr. Berghella from Thomas Jefferson University in Philadelphia published a fascinating new study on their randomized controlled trial allowing women an extra hour in the second stage of labor (here).

The authors assigned 78 first-time mothers in labor with a prolonged second stage to either three hours allowance for the second stage of labor or four hours allowance. (All of the women had epidurals, so three hours was the “control” arm and four hours was the “permissive” arm of the study.) They found that allowing an extra hour significantly decreased the cesarean delivery rate by about half, from 43% to 20%. More women in the four-hour group had a spontaneous vaginal delivery (i.e. not an operative vaginal delivery or c-section).

The authors also compared some common labor-related complications. There was no statistical difference in infections called chorioamnionitis or endometritis, postpartum hemorrhage, blood transfusions, severe vaginal tears (3rd or 4th degree lacerations), or cervical tears. There were, however, more postpartum hemorrhages in the four-hour group: 20% versus 8%. There were also more severe vaginal tears in the four-hour group: 15% versus 3%. However, because the sample size was small, the study was not powered to be able to detect whether this difference was due to chance or reflects a truly increased risk of hemorrhage or tearing with a longer second stage of labor.

This fascinating new research pushes the boundaries of what we currently know about the optimal length of the pushing stage of labor and begs for further research with larger groups to probe further into the effects on complication rates.