How Long Can Labor Safely Be?

By regular contributor, Henci Goer

A few weeks ago Kathy Morelli wrote an S&S blog post about a study comparing labor patterns in the 1960s with labor patterns today. The contemporary data were collected by the U.S. Consortium on Safe Labor (CSL), a collection of 19 hospitals, 17 of them teaching institutions, whose primary purpose is 'to describe contemporary labor progression and to evaluate the timing of Cesarean delivery in women with labor protraction and arrest.' The study compared women with spontaneous labor onset at term who were carrying singleton, head-down babies and found that after adjustment for differences in maternal and pregnancy characteristics, labors take longer today despite substantially increased use of oxytocin augmentation. The authors attributed the increased length to changes in management practices and concluded: 'Since labor times are longer today than in the past, the benefit of extensive interventions such as oxytocin and cesarean delivery in modern labor management needs further evaluation'(Laughon, Branch, Beaver and Zhang, p. 14).

The question still on the table is at what point does increased risk of morbidity from continuing a prolonged labor outweigh the risks of cesarean surgery or instrumental vaginal delivery to curtail it? The CSL study doesn't answer that question, but we have two studies, one in a single institutionand the other a multicenter study, that provide means and extremes for duration of physiologic labor. Both studies were conducted in healthy women in spontaneous labor at term with a singleton, head down fetus who were cared for by midwives. No woman had oxytocin augmentation, epidural analgesia, or an instrumental vaginal or cesarean delivery. Let's compare data on first-time mothers since they are much more likely to experience progress delay.

*data only from women reaching full dilation
** data only from women having spontaneous birth

As you can see, labor averaged even longer in the physiologic groups without doing any harm to the newborns. As you can also see, the midwifery data blow active management concepts, now enshrined in partograms, out of the water. Setting 1 cm per hour as the threshold for abnormally slow progress-which allows 6 hours to go from 4 cm to 10-means augmenting first-time mothers dilating faster than the average rate!

The CSL investigators point out that half the cesareans in the entire CSL cohort were performed for 'failure to progress' or 'cephalopelvic disproportion' and reference another study of the cohort finding that 'a large percentage of women' (p. 12) had cesareans prior to active-phase labor. Indeed they did. Among first-time mothers with spontaneous labor onset who had cesareans for delayed progress, more than a quarter of them (28%) had the surgery at 5 cm dilation or less. Among induced labors, the percentage soared to half (53%).

Despite their concern about over use of oxytocin augmentation and operative delivery, the CSL investigators also note that the extra two hours of average labor duration in first-time mothers (compared with the 1960s cohort) cost Intermountain Healthcare hospitals, which managed 5439 vaginal births in first-time mothers in 2010, an extra $110.40 per labor, amounting to an annual excess cost of $600,466. They continue: 'The implications for healthcare systems and payors are obvious and should drive a reconsideration of modern-day labor process management with an eye towards process improvement' (p. 13). One wonders just what that process improvement might be. The 'time is money' argument certainly doesn't augur for recommendations to have patience and avoid intervening'especially not when intervening via cesarean surgery increases revenue as well as saves money.

They don't come right out and say so, but clearly the CSL investigators know they have documented a gross overuse of cesarean surgery to cut short (pun intended) perfectly normal labors that pose no excess risk to mothers or babies. The Consortium on Safe Labor has, in fact, exposed that labor in their participating hospitals isn't very . . . well, . . . safe. Women are ending up with major interventions they don't really need and, no doubt, some of them are experiencing unnecessarily their consequent complications. What is more, economics provides a perverse incentive for keeping it that way.

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