by Rita Rubin
"Failure to progress" in labor is a common reason for unplanned C-sections. Sometimes, though, it might simply be failure to wait.
Studies suggest that some doctors and patients can be too quick to abandon plans for a vaginal delivery. Those judgment calls help explain why C-section rates vary so much from hospital to hospital and doctor to doctor. For example, if you deliver at South Miami Hospital in Florida, you're more than five times more likely to have a C-section than if you're admitted to Zuni-Ramah Hospital in northwestern New Mexico.
In 1996, just over 7% of the babies born at Zuni-Ramah were delivered by cesarean. That same year, the C-section rate in the USA was nearly 21%. The hospital's amazingly low C-section rate occurred in a population of Zuni and Navajo women who had high rates of diabetes and preeclampsia, both risk factors for C-sections.
What was going on here? Lawrence Leeman, one of the family-practice doctors who delivers babies at Zuni-Ramah, and his wife, Rebecca Leeman, a certified nurse midwife, uncovered two main reasons for the hospital's low rate of cesareans. Because so few women delivered their first babies by cesarean, fewer were having repeat C-sections. Makes sense.
The other main reason for Zuni-Ramah's low C-section rate: First-time mothers were only about one-fifth as likely as their counterparts nationwide to have a cesarean for dystocia, which simply means slow or difficult labor.
Dystocia is a catch-all for a variety of problems. The mother's pelvis might be too small, or her uterine contractions too few or too weak to cause her cervix to dilate properly. The baby might be too big or in the wrong position. There could be a combination of these factors. Or the only problem might simply be a lack of patience on the part of the doctor and, sometimes, the mother herself.
Dystocia is thought to account for 30% of all C-sections in the USA, including as many as half of those performed on first-time mothers. If you consider that many women who deliver their first baby by cesarean end up scheduling repeat C-sections, the diagnosis of dystocia might be at least indirectly related to 50% to 60% of all cesareans.
Maybe the problem lies not with the women diagnosed with dystocia but with how doctors define the term. Women today are held to a half-century-old labor standard called the Friedman curve, one of the first things obstetrics students learn in their training.
Emanuel Friedman wasn't yet 30 when he plotted the eponymous scale in 1953, during his residency training in obstetrics and gynecology in New York. Friedman found that, on average, it took 2½ hours for the cervix to dilate from 4 to 10 centimeters.
"In the last 50 years, the Friedman curve pretty much dictated obstetric practice, at least in the United States," says Jun Zhang, an epidemiologist at the National Institute for Child Health and Human Development.
Several reports suggest that many cesareans performed for dystocia might be unnecessary. When labor appears to be stalled, doctors -- as well as patients -- often give up too quickly and move on to a C-section.
For example, a study of deliveries at 30 Los Angeles and Iowa hospitals found that about one-quarter of women who had cesareans for lack of progress were only in the very first phase of labor, called the latent phase, when the procedure was performed. Some hadn't begun to dilate.
That doesn't square with the American College of Obstetricians and Gynecologists' definition of dystocia: no dilation of the cervix and no descent of the baby for at least two hours during active labor.
Maybe, the Los Angeles and Iowa researchers suggest, doctors have become so comfortable performing C-sections that they've relaxed their definition of lack of progress in labor.
Zuni-Ramah, on the other hand, isn't even equipped to do cesarean deliveries. If two doctors agree that a C-section is needed, the patient must be transported to a bigger hospital 35 miles away. The Leemans speculate that the logistics of obtaining a C-section motivate doctors and patients to wait out slow labor. Such an approach apparently hasn't caused too many problems in either babies or mothers at Zuni-Ramah.