Passive Descent in Obese Nulliparous Gravidae

Obesity rates in reproductive aged women in the United States are rising. It is now universally accepted that obesity is associated with many adverse pregnancy outcomes and post-operative complications following cesarean section. Recent studies have also shown an increased rate of cesarean section in obese women, adding to the already elevated rate of complications and adverse outcomes. Given the increased a priori risk for obese patients, it is vital that the investigators reexamine management practices routinely used for normal weight women in this specific high-risk population. Passive descent has been shown to increase the spontaneous vaginal delivery rate in non-obese women; however, high quality studies have never been performed in obese women. the investigators hypothesize that passive descent could improve the spontaneous vaginal delivery rate in nulliparous, obese women with regional anesthesia. This study will randomize women to passive descent for ninety minutes or active pushing upon entry into the second stage. Further, given that passive descent is widely accepted in the midwifery literature and clinical practice, the investigators anticipate that a high-quality study in the physician literature could increase the dialogue between practitioners and lead to development of best practices in this high-risk population.

Management of the Second Stage of Labor in Obese Nulliparous Women by Either Passive Descent or Immediate Pushing.

Inclusion Criteria: Obese - body mass index (BMI) calculated as weight (kg)/ [height (m2)] greater than or equal to 30 as determined at the time of admission to labor and delivery Regional anesthesia Nulliparous (defined as no deliveries after 20 weeks gestation) Gestational age of 37 0/7 weeks and greater Singleton Pregnancy Exclusion Criteria: Body mass index (BMI) calculated as weight (kg)/ [height (m2)] less than 30 as determined at the time of admission to labor and delivery No regional anesthesia Multiparous Gestational age of less than 37 0/7 weeks Multiple gestations Maternal fever prior to second stage Severe fetal anomalies (incompatible with life)