Background
In 2010 the Consortium on Safe Labor published labor curves. It was proposed that the rate of cesarean delivery (CD) could be lowered by avoiding the diagnosis of arrest of dilation before 6 cm. However, there is little information on the uptake of the guidelines and on changes in CD rates that may have occurred.
Objective
To test the hypotheses that: 1) among patients laboring at term, rates of arrest of dilation disorders have decreased leading to a decrease in the rate of CD; 2) in the second stage, pushing duration prior to diagnosis of arrest of descent has increased also leading to reduction in the rate of CD for this indication. As a secondary aim, we investigated changes in maternal and neonatal morbidity.
Study Design
This was a secondary analysis of a prospective cohort study of all patients presenting at ≥ 37 weeks’ gestation from 2010–2014 with a non-anomalous vertex singleton and no prior history of CD. Rates of CD, arrest of dilation, and changes in rates of maternal and neonatal morbidity were calculated in crude and adjusted models. Cervical dilation at diagnosis of arrest of dilation, time spent at the maximal dilation prior to diagnosis of arrest of dilation, and time in the second stage prior to diagnosis of arrest of descent were compared over the study period.
Results
There were 7845 eligible patients. The CD rate in 2010 was 15.8% and in 2014 17.7% (p-trend 0.51). In patients undergoing CD for arrest of dilation, the median cervical dilation at the time of CD was at 5.5 cm in 2010 and 6.0 cm in 2014 (p-trend 0.94). In these patients, there was an increase in the time spent at last dilation: 3.8h in 2010 to 5.2h in 2014 (p-trend 0.02). There was no change in the frequency of patients diagnosed with arrest of dilation at <6 cm: 51.4% in 2010 and 48.6% in 2014 (p-trend 0.56). However, in these patients, the median time spent at the last cervical dilation was 4.0h in 2010 and 6.7h in 2014 (p-trend 0.046). There were 206 CDs for arrest of descent. The median pushing time in these patients increased in multiparous patients from 1.1h in 2010 to 3.4h in 2014 (p-trend 0.009); in nulliparous patients these times were 2.7h in 2010 and 3.8h in 2014 (p-trend 0.09). There was a significant trend towards increasing adverse neonatal and maternal outcomes (p<0.001 for each). The aOR for adverse maternal outcome for 2014 compared to 2010 was 1.66 (95%CI 1.27, 2.17); however considering only transfusion, hemorrhage, or infection, there was no difference (p-trend 0.96). The aOR of adverse neonatal outcome in 2014 compared to 2010 was 1.80 (95%CI 1.36, 2.36).
Conclusion
Despite significant changes in labor management that have occurred over the initial years since publication of the new labor curves and associated guidelines, the primary CD rate was not reduced and there has been an increase in maternal and neonatal morbidity in our institution. A randomized controlled trial is needed.