Protracted thoughts on protracted labor…
When I was an intern in Charleston, SC, I quickly learned the importance of the labor curve. When checking out with my chief, I was often asked the question “Is she on the curve?” Quickly I learned the idea that women that “fall off the curve” were in a dysfunctional labor pattern, and were more likely to require a cesarean delivery. I dutifully listened to all this, and did many a cesarean for active phase arrest. As a junior level I did the cesareans, and as chief I called them. But at the same time, I had doubts about all of this.
I’ve always thought that to deliver a baby by cesarean for an active phase arrest is to say either “I think this baby will not deliver” or “I think this baby will not deliver without injuring itself or the mother.” Certainly one of these things is clearly true in some occasions, demonstrated by the scores of women with vesicovaginal fistulas in countries where there is no ready access to cesarean delivery. But still, I always felt like the number of these cesarean deliveries was too high. It is really possible that ten or fifteen percent of pregnancies are destined to end in a baby so stuck it can never deliver without injury? Given the apparent success that is human reproduction, it just seemed unlikely to me.
The same thought has carried on to our management of the second stage. Early in my internship I was taught that if a primiparous woman with an epidural was not delivered after three hours of second stage labor, it was time for forceps or a cesarean section, and we did a lot of these as well. Some of these babies were massive, and the cesarean in those cases felt righteous. Nothing was more relieving than pulling out a ten or eleven pound baby from a hysterotomy. A shared smile between residents and a nod from the attending “that one wasn’t coming out from below!” But sometimes the baby was only 7 pounds, and one had to wonder if you could say the same. Was that average sized baby that wasn’t delivering really destined to die in there? Seemed unlikely.
Added on to all this was the apparent truth that cesareans for arrest were not distributed equally across 24 hours of the day. In fact, there were two prime times – late afternoon and around 4-5 AM: the few hours before the morning and afternoon board checkouts. Nobody wanted to leave this inevitable cesarean for the next team. Later in practice I saw these concerns coming into play even more among private practitioners who did not have the luxury of waiting for an unlikely vaginal delivery, being pressured by their full offices or waiting families. As was demonstrated by Steven Leavitt in Freakonomics, humans respond to incentives. And there are plenty of non-medical incentives to cut.
In my first position after residency at the University of Hawai’i, I saw a lot of women given a lot more time to deliver that Friedman would have recommended, and I saw that a lot of them delivered. Perhaps due to cultural differences, or perhaps because the patient to resident ratio precluded close following of every low risk mother, people weren’t in such a hurry to deliver protracted patients. And remarkably, a lot of mothers delivered that might have been cut where I had trained. But perhaps it was the population: wide pelviced Polynesians rather than African Americans, and fewer teenage mothers. It certainly played a part: after a few years I stopped being amazed at the ease at which a Samoan mother would deliver a ten or eleven pounder. The idea of pre-emptive section for macrosomia seemed almost ridiculous.
And so, I have many questions about this, none of which I have answers for. Was Friedman just wrong? Does his curve describe something that just doesn’t exist anymore? To be sure, the population he studied is not who we are caring for now. His population was primarily women without epidurals who entered active labor. We now use epidurals in the majority of labors, and labor induction is quite common, perhaps even the rule in some practices. And given the large effect of genetics I saw in just two different places, can we really extrapolate Friedman’s data to all women? And what about people who labor outside of the hospital? What percent of them meet the definition of arrest yet go on to deliver, blissfully ignorant of their temporary fetal impaction.
Clearly, I don’t have answers to all of this, but it does make me think – and it has changed my practice. I residency I pretty much cut when people hit two hours of arrest, and either pulled or cut at three hours of second stage. These days, I wait it out, particularly if the strip looks good. And I almost never cut a multiparous woman for arrest. It just is too bizarre to me that a woman who did it before wouldn’t be able to do it again.
My biggest problem with all this is the question of what I should be teaching my residents. Friedman’s curve is easy to teach, because it is objective. The problem is that it may not be right. But can I teach that it is wrong? And if so, what should I replace it with? I don’t know. For now I try to model benign neglect of putatively arrested women with reassuring fetal heart rate tracings…. at least until board checkout.