Cook´s Balloon Versus Dinoprostone for Labor Induction of Term Pregnancies With Fetal Growth Restriction (COLIGROW)

Cook´s Balloon Versus Dinoprostone for Labor Induction of Term Pregnancies With Fetal Growth Restriction

Cook´s Balloon Versus Dinoprostone for Labor Induction of Term Pregnancies With Fetal Growth Restriction (COLIGROW)

The goal of this clinical trial is to compare how two methods for cervical ripening work in a population of singleton pregnancies with late-onset fetal growth restriction (FGR) at term. The main question it aims to answer is whether Cook´s balloon (a mechanical method) is superior to vaginal dinoprostone (a pharmacological method) in achieving a vaginal delivery, without increasing neonatal morbidity. Participants will be randomized to receive Cook´s balloon (experimental group) or vaginal dinoprostone (control group) for cervical ripening. Researchers will compare both groups to see if Cook´s balloon is associated with a higher rate of vaginal delivery than vaginal dinoprostone and is not related to increased neonatal morbidity.

Late-onset fetal growth restriction (FGR) represents the most common subtype of FGR (70-80%). The greatest risk for these fetuses appears once term pregnancy is reached, when stressful situations are added to their status of relative hypoxia, such as the appearance of contractions and funicular compression. Thus, it has been shown that from week 37-38 the risk of intrauterine mortality increases and there is a general consensus not to prolong these pregnancies beyond this period. In this situation, induction of labor is usually preferred over elective caesarean delivery. However, these fetuses have an increased risk of cesarean section for suspected fetal distress. Mechanical methods for cervical ripening are associated with less uterine stimulation with a lower rate of tachysystole than prostaglandins. Therefore, these methods have been proposed as the optimal approach for late-onset FGR, since they could reduce the rate of cesarean sections for suspected fetal distress. However, there is no published randomized controlled trials on the use of different methods of cervical ripening for labor induction in late-onset FGR. Thus, the investigators postulate that, in late-onset FGR, cervical ripening with a mechanical method (Cook´s balloon) achieves a higher percentage of vaginal deliveries than a pharmacological method (vaginal dinoprostone), being safe for both the mother and the newborn. The main aim of this study is to evaluate whether cervical ripening with Cook balloon for labor induction at term gestation of singleton pregnancies with late-onset FGR achieves a higher rate of vaginal delivery compared to the use of vaginal dinoprostone, without increasing neonatal morbidity.

Vaginal delivery system containing 10 mg dinoprostone (Prostaglandin E2) dispersed throughout its matrix and releasing approximately 0.3 mg/hour dinoprostone over a 24-hour period.

Dinoprostone vaginal insert, Controlled-release dinoprostone delivery system, Vaginal prostaglandin E2

To assess whether cervical ripening with a Cook balloon for induction of labor of term pregnancies with FGR increases the rates of vaginal delivery with respect to the use of vaginal dinoprostone, without increasing neonatal morbidity.

To assess whether cervical ripening with a Cook balloon for induction of labor of term pregnancies with FGR decreases the rates of cesarean sections due to suspected fetal distress with respect to the use of vaginal dinoprostone

Comparison of the time interval between the onset of cervical ripening and delivery between the two arms

To analyze the neonatal morbidity through the MAIN score (Morbidity assessment index for newborns) of neonatal morbidity and the duration of admissions to the Neonatal Intensive Care Unit (NICU).

Inclusion Criteria: Singleton pregnancy Age ≥ 18 years Gestational age (GA) dated by first trimester ultrasound ≥ 37+0 weeks Cephalic presentation Stage I fetal growth restriction, defined as the presence of at least one of these two criteria: Estimated fetal weight (EFW) < 3rd percentile EFW < 10th percentile and at least one of the following: 2.1) Umbilical artery pulsatility index > 95th percentile or 2.2) Cerebral-placental index < 5th percentile Bishop score < 7 Intact fetal membranes No previous caesarean section No contraindications for vaginal delivery or labor induction. Exclusion Criteria: Major fetal malformation Fetal genetic abnormality Fetal congenital infection

De-identified IPD that underlies the results reported in the publication will be shared after publications of primary results upon request of investigators whose proposed research has received IRB approval and after data use agreement

Upon request of investigators whose proposed research has received IRB approval and after data use agreement