As of today, around 25% of all vaginal births happen after induction of labor (IOL). The internal guidelines of the University Hospital Zurich currently recommend pregnant women with a non-insulin dependent gestational diabetes an IOL around term. One possibility to prevent an IOL and increase the chance for a spontaneous onset of birth is a ripening of the cervix by alternative methods in an outpatient setting. The primary objective of this study is to evaluate the effect of natural cervical ripening methods on the time interval between 37 weeks (beginning of the intervention) and the onset of spontaneous labor.

Approximately 25% of vaginal births currently occur following induction of labor (IOL). At the University Hospital Zurich, internal guidelines recommend IOL at 40 weeks of gestation for women with non-insulin-dependent, diet-controlled gestational diabetes. However, IOL may be associated with side effects and a less positive birth experience. Alternative, natural methods for cervical ripening in an outpatient setting may help promote spontaneous labor onset and reduce the need for medical induction.

This investigator-initiated, mono-centric, prospective, randomized controlled trial aims to evaluate the effectiveness, safety, and feasibility of natural cervical ripening methods, specifically nipple stimulation (breast massage/colostrum harvesting) and membrane sweeping. The primary objective is to assess whether these interventions shorten the time from 37 weeks of gestation (start of intervention) to the onset of spontaneous labor.

The primary endpoint is the time interval between 37 weeks' gestation and spontaneous onset of labor. Secondary endpoints include the rate of spontaneous labor before planned IOL, oxytocin use during childbirth, use of pharmacological induction agents, duration of hospitalization, postpartum hemorrhage (>500 ml), mode of birth, patient satisfaction with the intervention/induction and birth experience, and neonatal outcomes.

The study includes 74 pregnant women aged ≥18 years with singleton pregnancies, diet-controlled gestational diabetes, planned vaginal birth, and scheduled IOL at 40 weeks, who can communicate in German or English and have provided informed consent. Key exclusion criteria include multiple gestation, fetal growth abnormalities, insulin-dependent diabetes, planned cesarean section, onset of labor prior to enrollment, or inability to comply with study procedures.

Participants are randomized to either an intervention group or a control group. The intervention group receives membrane sweeping twice weekly by medical personnel from 37 weeks, breast massage/nipple stimulation performed by the participant for 60 minutes on three days per week, and standard colostrum harvesting beginning at 36 weeks. The control group receives standard care only, consisting of colostrum harvesting twice daily from 36 weeks, which is already routine practice at the institution.

Data collection includes questionnaires during the intervention phase (assessing experience, compliance, and side effects) and after delivery (assessing satisfaction with the intervention or IOL and overall birth experience). Recruitment takes place during routine prenatal visits or at the lactation outpatient clinic of the University Hospital Zurich. Following informed consent and confirmation of eligibility, participants are enrolled and randomized.

The anticipated benefits include increased spontaneous onset of labor, reduced need for IOL and oxytocin, decreased postpartum hemorrhage, and improved maternal satisfaction with the birth experience. Given the natural nature of the interventions, risks are considered low, primarily mild vaginal bleeding or discomfort during membrane sweeping.

Inclusion Criteria:

• Singleton gestation
• Non-insulin dependent, dietetically managed gestational diabetes
• Greater than or equal to 34 weeks.
• Planned vaginal birth at the University Hospital of Zurich
• Planned IOL for 40 weeks of gestation.
• Communication in German and/or English language possible.

Exclusion Criteria:

• Pregnant women with multiple gestation
• Fetal macrosomia >95th percentile
• Intrauterine growth restriction <3rd percentile
• Already in labor (regular contractions or premature rupture of membranes (PROM)
• Patients scheduled for IOL before 40 weeks
• Insulin-dependent diabetes
• Planned cesarean section
• Planned birth in an external hospital
• Inability to follow the procedures e.g. due to language problems, psychological disorders