To assess patients' preference, understanding regarding elective IOL and factors contribute to decision making process towards elective IOL at 39th week of gestation.

A normal pregnancy lasts between 37+0 to 41+6 weeks. Estimated date of delivery is set exactly at 40+0 weeks of gestation. Base on this estimation, professional society's guidelines have recommended to start inducing the labor from 41+0 to 41+6 weeks after the last menstrual period. Clinical practice during the last few decades has been moving towards this trend and postponing labor induction.

But is 40 weeks' gestational age the optimal endpoint of human pregnancy? Recent studies, however, showed different results where many of them support induction of labor at 39 weeks. A large cohort retrospective study which included information from merely 5.4 million non-anomalous live births in the United States from 2012 to 2016, though only modestly, the authors have been able to conclude that the rates of composite neonatal and maternal adverse outcomes increase from 39 through 41 weeks of gestation among low-risk parous women. Stratifying by parity, it seemed that the trend is also similar among all low-risk women no matter which parities they are in. When it comes to nulliparous women, results from a large prospective randomized control trial (the ARRIVE trial) show that induction of labor at 39 weeks in low-risk nulliparous women did not lead to significant lower frequency of a composite adverse perinatal outcome but it did result in a significant lower rate of cesarean delivery. More recently, in a review sponsored by the Cochrane library on induction of labor beyond 37 weeks' gestation has found that there is a clear reduction in perinatal death with a policy of labor induction at or beyond 37 weeks compared with expectant management, though absolute rates are small (0.4 versus 3 deaths per 1000). There were also lower caesarean rates without increasing rates of operative vaginal births and there were fewer Neonatal Intensive Care Unit admissions with a policy of induction. Base on these evidence, the American College of Obstetricians and Gynecologists has suggested "it's time to induce of labor at 39th week of gestation". It is true that although induction of labor is familiar with obstetricians, the procedure is still raising concern from patients' side. Even in the United States where patients consulting has been routinely applied, the rate of patients refuse to be induced at 39th week of gestation is about 50%. Review from Cochrane library also suggested that "Offering women tailored counselling may help them make an informed choice between induction of labor for pregnancies" . In some countries where the National Guidelines still recommends induction of labor should be considered after 41 weeks of gestation and pregnancy related decisions are driven by many identical factors such as: knowledge, traditional or cultural ones, the patients' perspective on induction of labor before 40 weeks of gestation is a challenge. Thus, the patients' understanding of the elective induction of labor and factors contribute to decision-making process towards induction of labor should be investigated in order not only to develop appropriate induction policies for the future but also scientific studies/randomized clinical trials to come.

Inclusion Criteria:

• Maternal age ≥ 18
• Singleton pregnancy (twin gestation reduced to singleton, either spontaneously or therapeutically, is not eligible unless the reduction occurred before 14 weeks project gestational age)
• Gestational age at 36+0 weeks to 36+6 week
• Cephalic presentation
• No contraindications to vaginal delivery

Exclusion Criteria:

1. Previous C-section

2. Maternal medical illness associated with increased risk of adverse pregnancy outcome (any diabetes mellitus, any hypertensive disorders, cardiac diseases, renal insufficiency, systemic lupus erythematosus, mental disorders, HIV positive, use of heparin or low-molecular weight heparin during the current pregnancy etc.)

3. Abnormal placenta: Active vaginal bleeding greater than bloody show or placenta previa, accreta or vasa previa

4. Abnormal amniotic fluid volume:

   Oligohydramnios (MVP < 2cm) Polyhydramnios (MVP > 10cm)

5. Abnormal fetus Fetal demise or known major fetal anomalies Fetal growth restriction (FGR) (EFW < 3% or < 10% and abnormal Doppler) Non-reassuring fetal status (no fetal movements, abnormal fetal heart rate at auscultation)

Low risk pregnant women with a gestational age at 36th week and 39th weeks