Cervical pessary for preventing preterm birth in singletons and twin pregnancies: an update systematic review and meta-analysis

To evaluate the effectiveness of cervical pessary in preventing preterm birth (PTB) and improving perinatal outcomes among singleton and twin pregnancies. Electronic databases were systematically searched from their inception until 14 March 2019. Randomized clinical trials comparing the effectiveness of cervical pessary placement with expectant management were included. The primary outcome was the incidence of PTB <34 weeks. Thirteen studies were included, involving eight studies about singleton and six studies about twin pregnancies. For singleton pregnancies with short cervical length, cervical pessary, comparing with expectant treatment, seemed have no effectiveness in preventing PTB <34 weeks (relative risk, 95% confidence interval, 0.73, 0.42–1.28), <37 weeks (0.69, 0.43–1.09), and <28 weeks (0.79, 0.42–1.48); while for twin pregnancies with short cervical length, cervical pessary also did not reduce the risk of PTB <34 weeks (0.81, 0.49–1.35), <37 weeks (0.93, 0.83–1.05), and <28 weeks (0.72, 0.38–1.38). However, cervical pessary seemed have the effectiveness of reducing the risk of spontaneous PTB <28 weeks (0.50, 0.25–0.99) and low birth weight (<1500 g) (0.68, 0.50–0.94) among twin pregnancies with short cervical length. In addition, cervical pessary increased the rate of vaginal discharge and did not improve perinatal outcomes among both singleton and twin pregnancies. Comparing with the expectant treatment, the effectiveness of cervical pessary for reducing the risk of PTB remains uncertain. Additional trials are warranted to further evaluate the effectiveness of cervical pessary.

本研究旨在评估宫颈托（cervical pessary）在预防单胎及双胎妊娠孕妇早产（preterm birth, PTB）、改善围产结局方面的有效性。研究系统检索了各电子数据库，检索时限为从建库至2019年3月14日，纳入对比宫颈托置入与期待治疗有效性的随机对照试验，主要结局指标为妊娠<34周的早产发生率。共纳入13项研究，包含8项单胎妊娠相关研究与6项双胎妊娠相关研究。对于宫颈长度较短的单胎妊娠孕妇，与期待治疗相比，宫颈托在预防妊娠<34周（相对风险[relative risk, RR]：0.73，95%置信区间[confidence interval, CI]：0.42~1.28）、<37周（RR：0.69，95%CI：0.43~1.09）及<28周（RR：0.79，95%CI：0.42~1.48）早产方面未显示出有效性；而对于宫颈长度较短的双胎妊娠孕妇，宫颈托同样未降低妊娠<34周（RR：0.81，95%CI：0.49~1.35）、<37周（RR：0.93，95%CI：0.83~1.05）及<28周（RR：0.72，95%CI：0.38~1.38）的早产风险。不过，针对宫颈长度较短的双胎妊娠孕妇，宫颈托可降低妊娠<28周自发性早产（RR：0.50，95%CI：0.25~0.99）与低出生体重儿（<1500g，RR：0.68，95%CI：0.50~0.94）的发生风险。此外，宫颈托会增加阴道分泌物发生率，且在单胎与双胎妊娠人群中均未改善围产结局。与期待治疗相比，宫颈托降低早产风险的有效性仍不明确，未来仍需开展更多研究以进一步评估宫颈托的临床有效性。