Level of perinatal care of the maternity unit and rate of cesarean in low-risk nulliparas.

OBJECTIVE

To analyze the influence of level of perinatal care of the maternity unit on the rate of cesarean delivery during labor among women with low-risk pregnancies.

METHODS

Using data from the PREMODA (PREsentation et MODe d'Accouchement: presentation and mode of delivery) study of 138 French maternity units, the delivery method in 3,654 low-risk nulliparas (live singleton fetus in cephalic presentation at term [37-41 weeks of gestation], born weighing 2,500-4,500 g, no uterine scar, no cesarean before labor, and no induction of labor for maternal or fetal disorders) was analyzed. Independent variables included maternal and fetal characteristics and the level of perinatal care of the maternity unit (level 1, 2a, 2b, and 3; where levels 2b and 3 routinely manage high-risk pregnancies). Univariable and multivariable analysis with a multilevel logistic model explored the factors associated with cesarean delivery during labor.

RESULTS

Overall, the rate of cesarean during labor was 11.7%. The rate was significantly higher in level 2b (odds ratio 1.5, 95% confidence interval 1.1-2.1) and 3 (odds ratio 1.3, 95% confidence interval 1.0-1.9) maternity units than in level 1 facilities. The size and status of the facilities did not significantly affect these rates. Risk factors for cesarean were older maternal age, non-French origin, gestational age of 41 weeks, male sex, and high birth weight.

CONCLUSION

Maternity units that frequently manage high-risk pregnancies (levels 2b and 3) have higher rates of cesareans during labor for their population of nulliparas at low risk than do facilities that deal mainly with low-risk pregnancies (level 1).

LEVEL OF EVIDENCE

II-2.