Study Design / N Type of patients Treatment / Timing Results
Prevention of preterm birth Prevention of preterm birth Prevention of preterm birth Prevention of preterm birth Prevention of preterm birth
Rai et al. 200930
DB, RCT / 150
History of sPTD 20–<37 weeks Singleton pregnancy Oral NMP 100 mg bd vs Placebo From 18–24 to 36 weeks or delivery Rate of PTD (<3 7 weeks) lower with oral NMP vs placebo (39.2% vs 59.5%, p = 0.002). Mean ± SD gestational age at delivery greater with oral NMP vs placebo (36.1 ± 2.66 vs 34.0 ± 3.25 weeks, p < 0.001). Oral NMP prevented sPTD between 28–<32 weeks (2.7% vs 20.3%; RR 0.20, 95% CI 0.05–0.73, p = 0.001) but not between 32–<34 weeks (RR 0.86, 95% CI 0.60–1.22, p = 0.85) or between 34–<37 weeks (RR 0.83, 95% CI 0.48–1.45, p = 1.00) [RR of PTD with oral NMP vs placebo with gestational age ≥ 37 weeks as reference]. Among patients requiring tocolysis, mean tocolysis-to-delivery interval longer with oral NMP vs placebo (49.7 vs 26.8 hours, p = 0.058).
Ashoush et al. 201731
DB, RCT / 212
History sPTD <37 weeks Singleton pregnancy Oral NMP 100 mg qds vs Placebo From 14–18 to 37 weeks or delivery Risk of sPTD (<37 weeks) lower with oral NMP vs placebo (44.7% vs 63.7%; RR 0.7, 95% CI 054–0.92, p = 0.01). Mean ± SD gestational age at delivery greater with oral NMP vs placebo (35.4 ± 2.7 vs 33.9 ± 2.9 weeks, p = 0.01). Patients who required tocolysis had a longer mean tocolysis-to-delivery interval (87 ± 45.5 vs 36 ± 14.2 hours, p < 0.001).
Glover et al. 201132
DB, RCT / 33
History sPTD >20–<37 weeks Singleton pregnancy Oral NMP 400 mg/day vs Placebo From 16–19 to 33 weeks Rate of sPTD (<37 weeks) numerically lower with oral NMP vs placebo, but statistical significance not achieved (26.3% [5/19] vs 57.1% [8/14]; RR 0.55, 95% CI 0.26–1.16, p = 0.15). Mean ± SD gestational age at delivery not significantly longer with oral NMP vs placebo (37.0 ± 2.7 vs 35.9 ± 3.8 weeks, p = 0.3).
Boelig et al. 201933
Meta-analysis30−32 / 386
History of sPTD <37 weeks Singleton pregnancy
Oral NMP vs Placebo
Risk of preterm birth decreased at <37 weeks gestation (relative risk [RR] 0.68; 95% CI 0.55−0.84) and at <34 weeks gestation (RR 0.55; 95% CI 0.43−0.71) with oral NMP vs placebo. Increased gestational age of delivery (mean difference 1.71 weeks; 95% CI 1.11−2.30) with oral NMP vs placebo.
Tariq et al. 201734
OB / 345
History of PTD Singleton (95%) or multiple pregnancy Oral NMP 400 mg/day From 15–20 weeks to delivery Oral NMP prevented PTD (<37 weeks) in 67% of patients, and PTD occurred in 33% of patients despite treatment. Mean gestational age at time of delivery 37.51 ± 1.34 weeks.
Natu et al. 201735
RET / 30
High-risk for preterm labour (history of preterm labour or abortion; infection or multiple gestation in current pregnancy) Singleton or multiple pregnancy Oral NMP vs Vaginal progesterone suppository From first trimestera
PTD rate was 40% (6/15) with oral NMP vs 26.7% (4/15) with vaginal progesterone. Statistical analysis was not performed.
Maintenance tocolysis Maintenance tocolysis Maintenance tocolysis Maintenance tocolysis Maintenance tocolysis
Noblot et al. 199136
DB, RCT / 44
Arrested preterm labour (tocolysis with ritrodrine)
Oral NMP 400 mg qds × 24 h then tds vs Placebo From start of tocolysis to 35 weeks or delivery Pregnancy prolongation (6.0 vs 6.4 weeks) or number of deliveries before 37 weeks (6 vs 8) not different between oral NMP and placebo. Total ritrodrine dose (863 vs 1370 mg; p < 0.05) and number of days of hospitalization (13.6 vs 17.8; p < 0.05) lower with oral NMP vs placebo.
Choudhary et al. 201437
DB, RCT / 90
Arrested preterm labour (successful tocolysis with nifedipine) Singleton pregnancy Oral NMP 200 mg/day vs Placebo From 48 hours after tocolysis to 37 weeks or delivery Mean ± SD latency period (days gained until delivery) longer with oral NMP vs placebo (33.29 ± 22.16 vs 23.07 ± 15.42 days, p = 0.013). Rate of PTD lower with oral NMP vs placebo (33% vs 58%, p = 0.034).