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NATIONAL HARBOR, Md. -- More than two-thirds of nulliparous women achieved vaginal delivery after outpatient induction of labor (IOL), the HOME INDUCTION randomized noninferiority trial found.

Out of nearly 300 Irish women who were induced at 39 weeks' gestation by vaginal prostaglandin (Propess/Cervidil) or osmotic cervical dilator (Dilapan-S), 72% achieved vaginal delivery. There were no significant adverse neonatal or maternal outcomes in any group, reported Sarah Nicholson, MBBCh, BAO, a specialist registrar and clinical tutor in obstetrics and gynecology at the Royal College of Surgeons in Ireland.

"We observed high vaginal delivery rates particularly in the 24-hour cervical ripening groups," Nicholson said in a presentation at the Society for Maternal-Fetal Medicine (SMFM) annual meeting.

Participants were induced into labor at the hospital, returned home for 12 to 24 hours alongside a safety checklist, then returned to the hospital to complete delivery. Healthy nulliparous women were randomized to one of three forms of initial cervical ripening: 12 hours of Dilapan-S (D12; n=88), 24 hours of Dilapan-S (D24; n=96), or 24 hours of Propess (P24; n=87).

For both Propess and Dilapan-S 24-hour groups, vaginal birth rates were similar at 76% and 75%, respectively. However, only 64% of those in the Dilapan-S 12-hour group delivered vaginally. Thus, the noninferiority criteria for Dilapan-S to P24 was not met (-6%, 95% CI -17% to 5%, P=0.258).

Nicholson noted that the presented at SMFM several years ago resulted in on elective induction for low-risk nulliparous women at term.

"The reality is that many potentially eligible women cannot access induction of labor even when they choose this, often because of logistical challenges," Nicholson said. "These logistical challenges include increasing numbers of inductions being performed, as well as the practical reality that many obstetric hospitals have space and staffing challenges that limit access to induction on demand."

David Hackney, MD, a maternal-fetal medicine doctor at Case Western Reserve University in Cleveland, told 番茄社区 that "one of the things that makes obstetricians in the U.S. nervous about home induction is the potential for uncommon but adverse events" and that "those are always difficult to power in a study." He also noted that U.S. physicians might be more hesitant to have part of the induction phases at home because they operate in a different medical legal environment than European physicians.

Nicholson concluded that the trial "confirmed the safety and efficacy of outpatient induction ... and therefore, we can continue to empower women to make a preferred and evidence-based choice in terms of their journey through pregnancy while still being able to normalize the process of induction of labor."

The study took place at Ireland's largest obstetric hospital which has more than 9,000 annual deliveries. A total of 327 participants were recruited and randomized and 271 completed induction. Women between 18 and 39 with a singleton pregnancy and no contraindications to IOL, who also had a Bishop score of <6 at IOL, and who lived less than 30 minutes or 10 miles away were eligible. Multiparous women and women with BMIs greater than 35 were excluded.

The primary outcome was rate of achieving vaginal delivery, and secondary outcomes included various maternal and neonatal outcomes, logistical data, among other measures. The goal was to compare efficacy and safety of various IOL methods and there were no differences in baseline characteristics between the three groups; all had a mean maternal age of 27, mean BMI of around 25, and a median Bishop score of 1.

Among secondary maternal outcomes, uterine hyperstimulation was significantly more likely in the P24 group (3%) and did not occur in either Dilapan-S group (P=0.032) though it didn't have a clinical impact. More women in the Dilapan-S groups needed additional prostaglandin gel (71% for D24 and 51% for D12) compared to just 34% in the Propess group (P<0.001). Women in the Propess group had earlier removal of the induction agent (44%) compared to either Dilapan-S group (13% for D24 and 6% for D12; P<0.001). There were no differences among secondary neonatal outcomes.

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