Serial Change in Cervical Length for the Prediction of Emergency Cesarean Section in Placenta Previa

Abstract

PurposeTo evaluate whether serial change in cervical length (CL) over time can be a predictor for emergency cesarean section (CS) in patients with placenta previa.MethodsThis was a retrospective cohort study of patients with placenta previa between January 2010 and November 2014. All women were offered serial measurement of CL by transvaginal ultrasound at 19 to 23 weeks (CL1), 24 to 28 weeks (CL2), 29 to 31 weeks (CL3), and 32 to 34 weeks (CL4). We compared clinical characteristics, serial change in CL, and outcomes between the emergency CS group (case group) and elective CS group (control group). The predictive value of change in CL for emergency CS was evaluated.ResultsA total of 93 women were evaluated; 31 had emergency CS due to massive vaginal bleeding. CL tended to decrease with advancing gestational age in each group. Until 29–31 weeks, CL showed no significant differences between the two groups, but after that, CL in the emergency CS group decreased abruptly, even though CL in the elective CS group continued to gradually decrease. On multivariate analysis to determine risk factors, only admissions for bleeding (odds ratio, 34.710; 95% CI, 5.239–229.973) and change in CL (odds ratio, 3.522; 95% CI, 1.210–10.253) were significantly associated with emergency CS. Analysis of the receiver operating characteristic curve showed that change in CL could be the predictor of emergency CS (area under the curve 0.734, p < 0.001), with optimal cutoff for predicting emergency cesarean delivery of 6.0 mm.ConclusionsPrevious admission for vaginal bleeding and change in CL are independent predictors of emergency CS in placenta previa. Women with change in CL more than 6 mm between the second and third trimester are at high risk of emergency CS in placenta previa. Single measurements of short CL at the second or third trimester do not seem to predict emergency CS.

The Risk Factors for Antenatal Bleeding in Pregnancy with Placenta Previa

“…After that, cervical length in the bleeding group decreased abruptly. This serial change in cervical length was significantly associated with antenatal bleeding [14]. In our study, uterine cervical length measurement during the third trimester of pregnancy was not predictive of antenatal bleeding.…”

“…Therefore, sonographic findings predicting preterm labor may be more meaningful for antenatal hemorrhage than sonographic findings predicting placental adhesion. Thus, it has been reported that cervical length in the third trimester of pregnancy is helpful for predicting antenatal bleeding [12,14,15]. However, Hasegawa et al did not attempt to measure cervical length [13].…”

Prevalence of antepartum hemorrhage in women with placenta previa: a systematic review and meta-analysis

“…Twenty-five retrospective and four prospective cohort studies involving a total of 4687 individuals were included in the study (Table 1). Fourteen1516171819202122232425262728 took place in Asia, eight529303132333435 in North America, six101136373839 in Europe, and one40 in Africa. The articles were published between 1985 and 2016, and the median number of participants per study was 162 (range, 40–703).…”

Placenta and Transvaginal Sonography

“…1 The distance of a low-lying placenta from the internal os does not seem to influence the risk of antepartum bleeding. This is more influenced by cervical length [30][31][32] and the presence of an echo-free space (Fig. 6) in the lower edge of the placenta overlying the internal os 33 (Fig.…”