. Author manuscript; available in PMC: 2014 Dec 1.

Published in final edited form as: Am J Obstet Gynecol. 2013 Jul 24;209(6):551.e1–551.e18. doi: 10.1016/j.ajog.2013.07.022

TABLE 4.

Transdermal nitroglycerin compared with nifedipine and magnesium sulfate

Outcome	Number of trials	Number of events/total number or total number		Relative risk or mean difference (95% CI)	I² (%)
Outcome	Number of trials	Nitroglycerin	Other tocolytic	Relative risk or mean difference (95% CI)	I² (%)
Transdermal nitroglycerin compared with nifedipine
Delivery within 48 hours of treatment	1⁶⁷	4/26	3/24	1.23 (0.31–4.94)	NA
Recurrent preterm labor	1⁶⁷	7/26	4/24	1.62(0.54–4.83)	NA
Any maternal side effect	1⁶⁷	9/26	5/24	1.66 (0.65–4.26)	NA
Headache	1⁶⁷	8/26	2/24	3.69 (0.87–15.69)	NA
Flushing	1⁶⁷	2/26	1/24	1.85 (0.18–19.08)	NA
Maternal tachycardia	1⁶⁷	0/26	1/24	0.31 (0.01–7.23)	NA
Hypotension	1⁶⁷	1/26	3/24	0.31 (0.03–2.76)	NA
Nausea/vomiting	1⁶⁷	2/26	3/24	0.62 (0.11–3.37)	NA
Transdermal nitroglycerin compared with magnesium sulfate
Pregnancy prolongation, days	1⁶⁸	21	21	1.4 (−7.4 to 10.2)	NA

CI, confidence interval; NA, not applicable; NICU, neonatal intensive care unit