Outpatient Labor Induction Using Oral Misoprostol in Norway

The labor induction rate in Norway has increased from 10,5 % in 2000 to 26,1 % in 2019. This represents an important shift in the obstetric care, making labor induction one of the most common obstetrical interventions. The increase alters the population being induced, as it now includes more low-risk births compared to 20 years ago. The low risk labor inductions might not require the same repeated cardiotocography and inpatient care before onset of active labor as complicated pregnancies.

In 2017, a 25 μg misoprostol tablet for oral administration was approved for labor induction in the Nordic countries. Oral administration is user friendly, and low-dose orally administrated misoprostol is considered to have a favorable safety profile compared to many other induction methods, with low risk of hyperstimulation.

Despite the widespread knowledge of the importance of women´s labor experience for her future health, this aspect is rarely thoroughly explored in the vast number of studies on labor induction. For outpatient labor induction to work, it must be an alternative women find beneficial, as well as clinicians and the health care system.

Aim

The overall aim of this study is to investigate if outpatient induction of labor is beneficial in a Norwegian setting. This includes:

Study A. To investigate the clinical outcomes and feasibility of inducing in an outpatient setting compared to an inpatient setting in Norway Study B. To explore low-risk nulliparous women's experiences of labor induction in inpatient and outpatient settings.

Design and methods

Study A is a prospective non-randomized multicenter pilot- and feasibility study. Data are collected from the patient's electronical records. Study B is a mixed methods cross-sectional diary study, collecting data from the participants diaries and questionnaire and their electronical records. Both studies include the same participants.

In both the inpatient and outpatient regime, the women are induced with 25 μg misoprostol tablets administrated orally every two hours. Some of the women will be induced using a balloon catheter before misoprostol. In the inpatient regime, cardiotocography (CTG) will be performed according to standard protocol; every 4-6 hours or on indication. In the outpatient protocol, a CTG will be carried out before and after the administration of the first misoprostol. If the CTG is normal and the woman has no contractions, the woman can go home, provided a normal ultrasound scan from the last three weeks. An appointment will be set up no later than 24 hours later for a new CTG and assessment of the induction process and the health of the woman and fetus. If the woman goes home after this consultation, she will return no later than 24 hours later for inpatient labor induction if the labor does not start.

Women choosing the outpatient protocol will receive oral and written information about what they should be aware of and when to contact the maternity ward. They are welcome to contact the maternity ward at any time to seek advice from a midwife with experience in labor induction.

Inclusion criteria

• Healthy nulliparous women
• A single, healthy fetus in cephalic presentation at gestational age of 37 weeks or more
• Normal pregnancy
• The woman can read and communicate in Norwegian
• No cognitive barriers
• BMI 15,5-39,9
• Reside within one hour from the hospital
• Indication for labor induction is post term pregnancy, uncomplicated pre labor rupture of membranes, maternal wish or other indications determined as low-risk by the attending obstetrician

Exclusion criteria

• Known uterine abnormality or previous uterine surgery
• Major maternal medical illness requiring monitoring of mother or fetus in early labor
• Maternal infection
• Pregnancy complications such as preeclampsia, poorly controlled hypertension or medically treated diabetes mellitus
• Active vaginal bleeding characterized as more than bloody show
• Smoking
• Non-reassuring cardiotocography or reduced fetal movement
• Fetal growth EFW < 10th percentile or >90th percentile
• Poly- or oligohydramnios
• Known abnormalities in the placenta or umbilical cord