NifedipineversusTerbutaline, Tocolytic Effectiveness and Maternal and Neonatal Adverse Effects: A Randomized, Controlled Pilot Trial

A Comparative Study of the Effectiveness of Transdermal Nitroglycerine Patches and Oral Nifedipine in Prolongation of Pregnancy in Women With Preterm Labour

Backgrounds A significant contributor to newborn morbidity and mortality is preterm birth. Several techniques have been employed to identify patients at risk of premature labour. However, these predictors are not always effective because of their multifactorial aetiology. Preterm labour can be suppressed largely through tocolysis. This study compared the effectiveness and safety of transdermal nitroglycerine and oral nifedipine in preventing premature labour. Methods This study was done at Acharya Vinoba Bhave Rural Hospital, Sawangi, Wardha, Maharashtra, from December 2020 to November 2022, on 130 women presenting with preterm labour pains between 28 and 37 weeks of gestational age. All the women selected were randomized into two equal groups by using the envelope method. Sixty-five women were given a nitroglycerine patch (Group A), and the rest (65 women) were given an oral nifedipine tablet (group B). The variables studied were mean days of prolongation of pregnancy, treatment outcome, steroid coverage, along with feto-maternal outcomes among both groups. Results The percentage of women whose pregnancy was prolonged for at least 48 hours in the nitroglycerine group was 75.3%, and in the nifedipine group it was 93.8%. Failure to achieve tocolysis, defined as delivery within 48 hours, was seen significantly more in the nitroglycerine group (24.6%) than in the nifedipine group (6.1%). The overall foetal outcomes were comparable in both groups. Conclusion Oral nifedipine was found to be superior to transdermal nifedipine patches in terms of efficacy and safety in the management of preterm labour, with a better side effect profile.

Tocolytics for delaying preterm birth: a network meta-analysis (0924)

BACKGROUND

Preterm birth is the leading cause of death in newborns and children. Tocolytic drugs aim to delay preterm birth by suppressing uterine contractions to allow time for administration of corticosteroids for fetal lung maturation, magnesium sulphate for neuroprotection, and transport to a facility with appropriate neonatal care facilities. However, there is still uncertainty about their effectiveness and safety.

OBJECTIVES

To estimate relative effectiveness and safety profiles for different classes of tocolytic drugs for delaying preterm birth, and provide rankings of the available drugs.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov (21 April 2021) and reference lists of retrieved studies.

SELECTION CRITERIA

We included all randomised controlled trials assessing effectiveness or adverse effects of tocolytic drugs for delaying preterm birth. We excluded quasi- and non-randomised trials. We evaluated all studies against predefined criteria to judge their trustworthiness.

DATA COLLECTION AND ANALYSIS

At least two review authors independently assessed the trials for inclusion and risk of bias, and extracted data. We performed pairwise and network meta-analyses, to determine the relative effects and rankings of all available tocolytics. We used GRADE to rate the certainty of the network meta-analysis effect estimates for each tocolytic versus placebo or no treatment.

MAIN RESULTS

This network meta-analysis includes 122 trials (13,697 women) involving six tocolytic classes, combinations of tocolytics, and placebo or no treatment. Most trials included women with threatened preterm birth, singleton pregnancy, from 24 to 34 weeks of gestation. We judged 25 (20%) studies to be at low risk of bias. Overall, certainty in the evidence varied. Relative effects from network meta-analysis suggested that all tocolytics are probably effective in delaying preterm birth compared with placebo or no tocolytic treatment. Betamimetics are possibly effective in delaying preterm birth by 48 hours (risk ratio (RR) 1.12, 95% confidence interval (CI) 1.05 to 1.20; low-certainty evidence), and 7 days (RR 1.14, 95% CI 1.03 to 1.25; low-certainty evidence). COX inhibitors are possibly effective in delaying preterm birth by 48 hours (RR 1.11, 95% CI 1.01 to 1.23; low-certainty evidence). Calcium channel blockers are possibly effective in delaying preterm birth by 48 hours (RR 1.16, 95% CI 1.07 to 1.24; low-certainty evidence), probably effective in delaying preterm birth by 7 days (RR 1.15, 95% CI 1.04 to 1.27; moderate-certainty evidence), and prolong pregnancy by 5 days (0.1 more to 9.2 more; high-certainty evidence). Magnesium sulphate is probably effective in delaying preterm birth by 48 hours (RR 1.12, 95% CI 1.02 to 1.23; moderate-certainty evidence). Oxytocin receptor antagonists are probably effective in delaying preterm birth by 48 hours (RR 1.13, 95% CI 1.05 to 1.22; moderate-certainty evidence), are effective in delaying preterm birth by 7 days (RR 1.18, 95% CI 1.07 to 1.30; high-certainty evidence), and possibly prolong pregnancy by 10 days (95% CI 2.3 more to 16.7 more). Nitric oxide donors are probably effective in delaying preterm birth by 48 hours (RR 1.17, 95% CI 1.05 to 1.31; moderate-certainty evidence), and 7 days (RR 1.18, 95% CI 1.02 to 1.37; moderate-certainty evidence). Combinations of tocolytics are probably effective in delaying preterm birth by 48 hours (RR 1.17, 95% CI 1.07 to 1.27; moderate-certainty evidence), and 7 days (RR 1.19, 95% CI 1.05 to 1.34; moderate-certainty evidence). Nitric oxide donors ranked highest for delaying preterm birth by 48 hours and 7 days, and delay in birth (continuous outcome), followed by calcium channel blockers, oxytocin receptor antagonists and combinations of tocolytics. Betamimetics (RR 14.4, 95% CI 6.11 to 34.1; moderate-certainty evidence), calcium channel blockers (RR 2.96, 95% CI 1.23 to 7.11; moderate-certainty evidence), magnesium sulphate (RR 3.90, 95% CI 1.09 to 13.93; moderate-certainty evidence) and combinations of tocolytics (RR 6.87, 95% CI 2.08 to 22.7; low-certainty evidence) are probably more likely to result in cessation of treatment. Calcium channel blockers possibly reduce the risk of neurodevelopmental morbidity (RR 0.51, 95% CI 0.30 to 0.85; low-certainty evidence), and respiratory morbidity (RR 0.68, 95% CI 0.53 to 0.88; low-certainty evidence), and result in fewer neonates with birthweight less than 2000 g (RR 0.49, 95% CI 0.28 to 0.87; low-certainty evidence). Nitric oxide donors possibly result in neonates with higher birthweight (mean difference (MD) 425.53 g more, 95% CI 224.32 more to 626.74 more; low-certainty evidence), fewer neonates with birthweight less than 2500 g (RR 0.40, 95% CI 0.24 to 0.69; low-certainty evidence), and more advanced gestational age (MD 1.35 weeks more, 95% CI 0.37 more to 2.32 more; low-certainty evidence). Combinations of tocolytics possibly result in fewer neonates with birthweight less than 2500 g (RR 0.74, 95% CI 0.59 to 0.93; low-certainty evidence). In terms of maternal adverse effects, betamimetics probably cause dyspnoea (RR 12.09, 95% CI 4.66 to 31.39; moderate-certainty evidence), palpitations (RR 7.39, 95% CI 3.83 to 14.24; moderate-certainty evidence), vomiting (RR 1.91, 95% CI 1.25 to 2.91; moderate-certainty evidence), possibly headache (RR 1.91, 95% CI 1.07 to 3.42; low-certainty evidence) and tachycardia (RR 3.01, 95% CI 1.17 to 7.71; low-certainty evidence) compared with placebo or no treatment. COX inhibitors possibly cause vomiting (RR 2.54, 95% CI 1.18 to 5.48; low-certainty evidence). Calcium channel blockers (RR 2.59, 95% CI 1.39 to 4.83; low-certainty evidence), and nitric oxide donors probably cause headache (RR 4.20, 95% CI 2.13 to 8.25; moderate-certainty evidence).

AUTHORS' CONCLUSIONS

Compared with placebo or no tocolytic treatment, all tocolytic drug classes that we assessed (betamimetics, calcium channel blockers, magnesium sulphate, oxytocin receptor antagonists, nitric oxide donors) and their combinations were probably or possibly effective in delaying preterm birth for 48 hours, and 7 days. Tocolytic drugs were associated with a range of adverse effects (from minor to potentially severe) compared with placebo or no tocolytic treatment, although betamimetics and combination tocolytics were more likely to result in cessation of treatment. The effects of tocolytic use on neonatal outcomes such as neonatal and perinatal mortality, and on safety outcomes such as maternal and neonatal infection were uncertain.

Comparison of the efficacy of the immediate-release and osmotic push-pull system formulations of nifedipine for tocolysis

AIM

To compare the immediate-release (IR) and osmotic push-pull system formulations of nifedipine used for tocolysis in prolonging pregnancy, neonatal outcomes and maternal-fetal adverse effects.

METHODS

We evaluated 140 pregnant women who received the IR (n = 72) and osmotic push-pull system (n = 68) formulations of nifedipine for tocolysis due to threatened preterm labor between 24^0/7 and 33^6/7 weeks of gestation. Groups were compared in terms of efficacy of tocolysis in prolonging pregnancy for more than 48 h, 7 days and up to 37 weeks of gestation, total number of days gained for prolonging pregnancy, delivery weeks, maternal-fetal adverse effects and neonatal outcomes including ventilation support, need for intubation or surfactant, intraventricular hemorrhage, respiratory distress syndrome, necrotizing enterocolitis, admission to neonatal intensive care unit, neonatal death, Apgar scores at the 1st and 5th minutes.

RESULTS

There was no significant difference between the two groups in prolonging pregnancy for more than 48 h or 7 days, total number of days gained after tocolysis initiation, delivery weeks, the number of births at 34^0/7 -36^6/7 weeks or after 37 weeks of gestation (P > 0.05). Maternal-fetal adverse effects and neonatal outcomes were similar in both groups (P > 0.05).

CONCLUSION

The efficacy of IR and osmotic push-pull system formulations of nifedipine have similar effects in terms of tocolysis and neonatal outcomes, adverse effects. Osmotic push-pull system formulation of nifedipine may be an alternative medication in tocolytic therapy due to its ease of use and the absence of loading dose necessity.