Modified Delphi study of ultrasound signs associated with placenta accreta spectrum.

OBJECTIVE: To determine, by expert consensus through a modified Delphi process, the role of standardized and new ultrasound signs in the prenatal evaluation of patients at high risk of placenta accreta spectrum (PAS). METHODS: A systematic review of articles providing information on ultrasound imaging signs or markers associated with PAS was performed before the development of questionnaires for the first round of the Delphi process. Only peer-reviewed original research studies in the English language describing one or more new ultrasound sign(s) for the prenatal evaluation of PAS were included. A three-round consensus-building Delphi method was then conducted under the guidance of a steering group, which included nine experts who invited an international panel of experts in obstetric ultrasound imaging in the evaluation of patients at high risk for PAS. Consensus was defined as agreement of ≥ 70% between participants. RESULTS: The systematic review identified 15 articles describing eight new ultrasound signs for the prenatal evaluation of PAS. A total of 35 external experts were approached, of whom 31 agreed and participated in the first round. Thirty external experts (97%) and seven experts from the steering group completed all three Delphi rounds. A consensus was reached that a prior history of at least one Cesarean delivery, myomectomy or PAS should be an indication for detailed PAS ultrasound assessment. The panelists also reached a consensus that seven of the 11 conventional signs of PAS should be included in the examination of high-risk patients and the routine mid-gestation scan report: (1) loss of the 'clear zone', (2) myometrial thinning, (3) bladder-wall interruption, (4) placental bulge, (5) uterovesical hypervascularity, (6) placental lacunae and (7) bridging vessels. A consensus was not reached for any of the eight new signs identified by the systematic review. With respect to other ultrasound features that are not specific to PAS but increase the probability of PAS at birth, the panelists reached a consensus for the finding of anterior placenta previa or placenta previa with cervical involvement. The experts were also asked to determine which PAS signs should be quantified and consensus was reached only for the quantification of placental lacunae using an existing score. For predicting surgical outcome in patients with a high probability of PAS at delivery, a consensus was obtained for loss of the clear zone, bladder-wall interruption, presence of placental lacunae and presence of placenta previa involving the cervix. CONCLUSIONS: We have confirmed the continued importance of seven established standardized ultrasound signs of PAS, highlighted the role of transvaginal ultrasound in evaluating the placental position and anatomy of the cervix, and identified new ultrasound signs that may become useful in the future prenatal evaluation and management of patients at high risk for PAS at birth. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Trends in provider-initiated versus spontaneous preterm deliveries, 2004-2013.

OBJECTIVE: The objectives of this study were as follows: (i) to estimate the proportion of preterm deliveries at a tertiary perinatal center that were provider-initiated versus spontaneous before and after a 2009 policy to reduce elective early-term deliveries, and (ii)to evaluate whether shifts in type of preterm delivery varied by race/ethnicity. METHOD: We performed a retrospective cohort study of preterm deliveries over a 10-year period, 2004 to 2013, including detailed review of 929 of 5566 preterm deliveries, to designate each delivery as provider-initiated or spontaneous. We dichotomized the time period into early (2004 to 2009) and late (2010 to 2013). We used log-binomial regression to calculate adjusted risk ratios. RESULT: Of the 46 981 deliveries, 5566 (11.8%) were preterm, with a significant reduction in the overall incidence of preterm delivery from 12.3 to 11.2% (P=0.0003). Among the 929 preterm deliveries analyzed, there was a reduction in the proportion of provider-initiated deliveries from 48.3 to 41.8% that was not statistically significant. The proportion of provider-initiated preterm deliveries among Black, but not White, women declined from 50.8 to 39.7% (adjusted relative risk: 0.66; 95% confidence interval (CI): 0.45 to 0.97). This coincided with a larger reduction in overall preterm deliveries among Black women (16.2 to 12.8%) vs White women (12.3 to 11.2%) (P interaction=0.038). By 2013, the incidence of preterm deliveries had decreased for both Black (12.1%) and White women (11.4%), and the difference was no longer statistically significant (P=0.7). CONCLUSION: We found a reduction in preterm deliveries after a policy targeted at reducing elective early-term deliveries in 2009 that coincided with reductions in the proportion of provider-initiated preterm deliveries, especially among Black women.