Introduction: To compare the effect of a policy of screening for
spontaneous preterm delivery (SPD) by transvaginal cervical length (CL)
measurement versus a no screening policy in the prevention of severe
prematurity. Methods: Retrospective study on low risk singleton
pregnancies examined at 20-24 weeks. Two cohorts one with SPD screening
and the other without screening were matched using propensity analysis
to create the study groups. Women with short CL were treated with
vaginal progesterone and/or cervical cerclage/pessary. The outcomes
examined were SPD<32 weeks (SPD 32) and SPD between 20 and 32
weeks (SPD 20-32). Results: Screening for SPD was associated with a
significant reduction in the rate of SPD at less than 32 weeks (0.3% vs
0.8%, p=0.001 in the screened and no screened pregnancies respectively)
and in the rate of SPD 20-32 (0.3% vs 0.9%, p=0.005 in the screened
and no screened pregnancies respectively). After adjusting for maternal
age, parity, body mass index, smoking and mode of conception, the
screening group had significantly lower hazard for SPD 20-32 (HR=0.36,
95% CI: 0.18-0.75, p=0.006) and SPD32 (HR=0.39, 95% CI: 0.19-0.82,
p=0.013). Conclusion: Screening for SPD by transvaginal CL measurement
in mid pregnancy may reduce the incidence of severe prematurity in low
risk singleton pregnancies.