N. Kok

Sonographic measurement of lower uterine segment thickness to predict uterine rupture during a trial of labor in women with previous Cesarean section: a meta‐analysis

To evaluate the accuracy of antenatal sonographic measurement of lower uterine segment (LUS) thickness in the prediction of risk of uterine rupture during a trial of labor (TOL) in women with a previous Cesarean section (CS).

Systematic review of accuracy of ultrasound in the diagnosis of vasa previa

Vasa previa is an obstetric complication in which the fetal blood vessels lie outside the chorionic plate in close proximity to the internal cervical os. In women with vasa previa, the risk of rupture of these vessels is increased, thus potentially causing fetal death or serious morbidity. Our objective was to assess the accuracy of ultrasound in the prenatal diagnosis of vasa previa.

Incidence of and risk indicators for vasa praevia: a systematic review

Vasa praevia (VP) is a rare phenomenon that is assumed to increase the risk of severe complications, including fetal death. Critical data on its incidence are lacking, so there is no rational basis for prenatal screening.

Severe postpartum haemorrhage and mode of delivery: a retrospective cohort study.

Objective To examine the association between intended mode of delivery and severe postpartum haemorrhage.

Risk of maternal and neonatal complications in subsequent pregnancy after planned caesarean section in a first birth, compared with emergency caesarean section: a nationwide comparative cohort study

To compare the difference in risks of neonatal and maternal complications, including uterine rupture, in a second birth following a planned caesarean section versus emergency caesarean section in the first birth.

OP25.06: Sonographic evaluation of the lower uterine segment in pregnant women with prior Caesarean section, a systematic review

Objectives: Localization of the placenta is traditionally performed transabdominally (TA) at the time of the routine 18–20 week scan. In circumstances where the placenta is described as being low, a second scan is arranged at 34 weeks gestation. Whilst the value of transvaginal (TV) assessment for cases with a posterior placenta at 34 weeks is well recognized, there is little data comparing TA and TV approaches earlier in pregnancy. This study compares TA and TV approaches to placental localization. Methods: The distance between the leading edge of the placenta and the internal cervical os were measured in a series of pregnancies presenting for routine obstetric ultrasound scans at 12–36 weeks gestation. Bland Altman plots and paired t-tests were used to look at the differences in TA and TV measurement and the screening efficacy of an initial TA assessment in defining a group for TV evaluation is also reported. Results: 282 consented to participate in the study. A Bland Altman plot shows that TA measurements overestimated the distance compared with the TV measurements; the average difference in measurement was 11.6 mm (95% CI: 4.4–18 mm). Assuming the TV scan measurements are the ‘gold standard’, TA assessment accurately predicted that the leading edge of the placenta was within 25 mm of the internal cervical os in 22/82 (27%) of cases assessed at 16–23 weeks and 1/2 (50%) of cases > 24 weeks. The specificity of the TA approach was 96% and 97% for these two categories respectively. Conclusions: TA sonography has a low sensitivity for detecting a low-lying placenta. Placental localization is best performed by transvaginal scan.