Revealed Versus Concealed Cerebroplacental Ratio

Revealed Versus Concealed Criteria for Placental Insufficiency in Unselected Obstetric Population in Late Pregnancy: a Multicenter Randomized Controlled Trial

The purpose of this study is to evaluate the role of an integrated strategy at selecting fetuses for delivery at term based on a combination of fetal biometry and cerebroplacental ratio (CPR) to reduce stillbirth rate and adverse perinatal outcome.

This is a multicenter, open-label randomized trial with groups in parallel. Singleton pregnancies are recruited after routine second trimester scan (19+0 to 22+6 weeks of gestation) and randomly allocated at that moment to revealed or concealed strategy. A routine scan will be booked at 36-37 weeks. For a reduction of the stillbirth rate of 3‰ (from 5‰ to 2‰), assuming a type I error of 5% and aiming for a power of 80% a total of 11,582 subjects (5791 per arm) were projected. The participating centers sum up 12,000 deliveries a year. It is not possible to blind participants, obstetricians, or outcome assessors to the study group. General hypothesis: A proportion of fetuses with "normal" growth as per current standards have placental insufficiency and restriction of their growth potential. These fetuses exhibit biophysical changes expressed by abnormal cerebroplacental ratio. A combination of this marker with fetal biometry for the detection of fetuses affected by fetal growth restriction could identify a group of babies on which labor induction once term is reached may prevent the occurrence of adverse outcomes. Specific hypothesis The cerebroplacental ratio has predictive value in late pregnancy for placental insufficiency. The cerebroplacental ratio could improve the effectiveness of late pregnancy screening for the prediction placental insufficiency-related complications.

Cerebroplacental ratio measurement at 37 weeks of pregnancy only taken into account if estimated fetal weight <p10

Cerebroplacental ratio measurement at 37weeks and labor induction in case of cerebroplacental ratio <p5

Inclusion Criteria: Viable singleton non-malformed fetus Available first-trimester US dating Maternal age at recruitment ≥18 years No adverse medical or obstetrical history at booking Capacity to give informed consent Exclusion Criteria: Abnormal karyotype Structural abnormalities Congenital infections

Figueras F, Gratacos E, Rial M, Gull I, Krofta L, Lubusky M, Cruz-Martinez R, Cruz-Lemini M, Martinez-Rodriguez M, Socias P, Aleuanlli C, Cordero MCP. Revealed versus concealed criteria for placental insufficiency in an unselected obstetric population in late pregnancy (RATIO37): randomised controlled trial study protocol. BMJ Open. 2017 Jun 15;7(6):e014835. doi: 10.1136/bmjopen-2016-014835. Erratum In: BMJ Open. 2019 Feb 19;9(2):e014835corr1.