RETRACTED ARTICLE: Efficient administration of a combination of nifedipine and sildenafil citrate versus only nifedipine on clinical outcomes in women with threatened preterm labor: a systematic review and meta-analysis

Preterm labor (PTL) is a common and serious pregnancy disorder thatcan cause long-term neurological issues in the infant. There are conflictingstudies concerning whether sildenafil citrate (SC) reduces preterm laborcomplications. Therefore, the meta-analysis aimed to examine the clinicaloutcomes in women with threatened PTL who received nifedipine plus SC therapyversus only nifedipine.

For the original articles, six databases were searched usingrelevant keywords without restriction on time or language until January 13,2024. The Cochrane risk-of-bias tool for randomized trials (RoB) and the Risk ofBias Assessment Tool for Nonrandomized Studies (RoBANS) were both used to assessthe risk of bias in randomized and non-randomized studies, and GRADE determinedthe quality of our evidence. Meta-analysis of all data was carried out usingReview Manager (RevMan) version 5.1.

Seven studies with mixed quality were included in the meta-analysis.The study found that combining nifedipine and SC resulted in more prolongationof pregnancy (MD = 6.99, 95% CI: 5.32, 8.65, p < 0.00001), a lower rate of delivery in the 1st to 3rd daysafter hospitalization (RR = 0.62, 95% CI: 0.50, 0.76, p < 0.00001), a higher birth weight (252.48 g vs. nifedipinealone, p = 0.02), and the risk ratio ofadmission to the neonatal intensive care unit (NICU) was significantly lower(RR = 0.62, 95% CI: 0.50, 0.76, p < 0.00001) compared to nifidepine alone. The evidence was highfor prolongation of pregnancy, delivery rate 24–72 h after admission, and NICUadmission, but low for newborn birth weight.

Given the effectiveness of SC plus nifedipine in increasedprolongation of pregnancy and birth weight, lower delivery in the 1st to 3rddays after hospitalization, and NICU admission, Gynecologists and obstetriciansare suggested to consider this strategy for PTL management, although additionalarticle rigor is required to improve the quality of the evidence.