Cervical assessment in women with hysteroscopic uterine septum resection: a retrospective cohort study.

Objective: To estimate whether cervical length measured by transvaginal ultrasonography in women with a history of hysteroscopic uterine septum resection predicts spontaneous preterm birth <35 weeks' gestation.

Methods: This retrospective cohort study compared women who had undergone hysteroscopic metroplasty, and were subsequently pregnant with singleton gestations delivered January 2003 to December 2012, to a low-risk control group. Transvaginal ultrasonographic cervical lengths were measured 16-30 weeks' gestation. The primary outcome was spontaneous preterm birth <35 weeks' gestation and the primary exposure variable of interest was cervical length.

Results: Women with a uterine septum resected (N = 24) had a shorter cervical length (2.90 cm) than the low-risk control group (N = 141, 4.31 cm, p < 0.0001); and were more likely to have a cervical length <3.0 cm (41.7% versus 1.4%, p < 0.0001), <2.5 cm (33.3% versus 0%, p < 0.0001), <2.0 cm (16.7% versus 0%, p < 0.0001) and <1.5 cm (12.5% versus 0%, p = 0.003). Women with septum resected were more likely to receive corticosteroids (33.3% versus 11.3%, p = 0.010), but were not more likely to have a spontaneous preterm birth <35 weeks (4.2% versus 0.7%, p = 0.27). There were no differences noted in secondary outcomes including neonatal morbidity.

Conclusion: Pregnant women with a history of a hysteroscopic uterine septum resection have shorter cervical lengths than low-risk controls but may not be at a higher risk of spontaneous preterm birth <35 weeks' gestation. Further research with a larger sample size is needed to evaluate this group of women to determine if transvaginal ultrasonographic cervical length assessment is of benefit.