The study intends to develop a predictive model of spontaneous onset of labor between 39 and 41 weeks of pregnancy in women carrying singletons and without indication of delivery before this date. The main hypothesis is that a combination of clinical, ultrasonographic, biochemical and/or biophysical variables will allow to differentiate women who will spontaneously trigger their labors from those who will require an induction by the term of their pregnancies. A tool of this kind should aid in the individualization of the management of the final weeks of pregnancy and, at the light of recent evidence, provide support to the decision-making processes.

Inclusion Criteria:

• Alive fetus
• Singletons
• Cephalic presentation
• Intact membranes
• Gestational age ≥ 38 weeks and 5 days

Exclusion Criteria:

• Fetal malformations
• Symptomatic uterine contractions
• Contraindication for vaginal delivery
• Medical indication of induction of labor or elective cesarean delivery
• Maternal desire to induce labor
• Maternal negative to enrollment
• Language barrier
• Inability to give consent

Specific Exclusion Criteria for Pregnolia System (if any of these criteria is present, the measurement of cervical stiffness using Pregnolia aspiration device will not be performed):

• Müllerian anomalies with two cervices

• Severe vaginal bleeding

• Cervical dilatation

• Known HIV

• Visible, symptomatic cervical or vaginal infections

• If one of the following conditions is present on the cervix at the 12 o'clock position:

  • Nabothian cyst
  • Cervical myomas
  • Cervical condylomas
  • Squamous intraepithelial lesion
  • Conization/LEEP2/LLETZ3
  • Cervical endometriosis
  • Cervical tears
  • Cervical dysplasia
  • Large ectopy, for which it is not possible to find a suitable location near the ectopy where native tissue is present
  • Large scar tissue, for which it is not possible to find a suitable location near the scar where native tissue is present.

Pregnant women at 38+5 - 39 weeks of gestation who will deliver at the centers in which the study will be carried out.