///2019 Abstract Details
2019 Abstract Details2019-07-13T07:45:15-05:00

The Safety and Feasibility of Intravenous Nitroglycerin Use In Women Undergoing Cesarean Delivery In The Second Stage of Labor

Abstract Number: F3B-289
Abstract Type: Original Research

Tina M Yu MD1 ; Stephanie Lim MD2; Jermaine Augustus MD3; Cinthia Blat MPH4; Mary Norton MD5; Jennifer Lucero MD6


Cesarean deliveries (CD) in the second stage of labor are challenging given frequent difficulty extracting the fetal head. Prolonged second stage of labor has been associated with hysterotomy extension, and maternal and neonatal morbidity. Nitroglycerin (NTG) may assist with difficult deliveries. We studied the safety and feasibility of IV NTG in patients undergoing second stage CD.


In a randomized controlled trial, patients were allocated to NTG versus saline by randomized calendar blocks with random block sizes. Women age 18-45 at >37 weeks gestational age undergoing CD in the second stage of labor were eligible. Obstetricians were blinded to allocation to allow for unbiased determination of hysterotomy extension; administering anesthesiologists were not. At uterine incision, a 400mcg bolus of NTG (200mcg/mL) or 2mL of saline was given followed by an infusion of 800mcg/min of IV NTG or equal amount of saline. Concomitant bolus of phenylephrine (100mcg/mL) was given with NTG. The infusion of study drug was discontinued after delivery of the fetus or when 1600mcg total NTG given. Obstetricians could ask for NTG as standard care and patients in the saline arm could cross over.


Among 18 patients consented in the study, 7 received IV NTG and 11 received saline. All CD were performed under epidural with 2% lidocaine. No adverse events were reported.

Maternal mean arterial blood pressure (MAP) at uterine incision was 88.6 (+ 10.1, ns) and MAP at neonate delivery was 85.6 (+ 7.0, ns). Phenylephrine bolus dose between the NTG versus saline group was statistically significant (385.7 mcg vs 63.6 mcg, p<0.05). Fetal extraction time with NTG was 104.9 sec (+ 33.1) versus 131.0 sec (+ 84.1), not significant.


This was a pilot safety and feasibility study of NTG at cesarean delivery on maternal and neonatal outcomes. Our study was stopped early for feasibility concerns, as enrollment was lower than anticipated. The study was not powered to detect a difference in fetal extraction time, although this would be an important outcome in future studies. We found no adverse outcomes when NTG was administered with phenylephrine. There was a trend toward shorter fetal extraction time and shorter operative time.

Isquick S., et al. The association between nitroglycerin use and adverse outcomes in women undergoing cesarean delivery in the second stage of labor. J Matern Fetal Neonatal Med. 2017; 30 (11): 1297-1301

SOAP 2019