To calculate sensitivity (SN), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) of PartoSure TTD test in predicting delivery within 7 or 14 days from testing and to compare it with cervical length (CL) measurement by transvaginal ultrasound (15 mm cut-off)

• This trial is a prospective observational study.
• Pregnancies after ART between 20 0/7 and 36 6/7 weeks with symptoms of preterm labor, clinically intact membranes, cervical dilatation of ≤ 2 cm will be invited to participate to the study. Signed consent form is required to be able to participate to the study.
• PartoSure and CL will be performed on all patients and the test-to-spontaneous-delivery interval will be calculated.
• Trial Population:Pregnancies after ART between 20 0/7 and 36 6/7 weeks with symptoms of preterm labor are hospitalized at My Duc hospital from October 2015 to April 2016. The sample size for this trial of 100 subjects.

Inclusion Criteria:

To be eligible for enrollment into this trial, each female subject must fulfill all of the following criteria at the start of enrollment:

• Pregnancies after assisted reproductive technology include singleton and twins
• Between 20 0/7 and 36 6/7 weeks with symptoms of preterm labor including uterine contractions, intermittent lower abdominal pain and pelvic pressure.
• Clinically intact membranes.
• Cervical dilatation of ≤ 2 cm
• Agree to participate in the study, and to disclose any medical events to the investigator
• Have given written informed consent

Exclusion Criteria:

To be eligible for enrollment in this study each subject must not meet any of the following criteria:

• Vaginal bleeding
• Overt rupture of the fetal membranes as indicated by visualized leakage of fluid from the cervix
• Placenta previa
• Cervical cerclage in place
• Received tocolytic medications for treatment of threatened preterm delivery prior to collection of the cervicovaginal specimens or CL measurement.
• Digital exam prior to specimen collection.
• A symptom not associated with idiopathic threatened preterm delivery (e.g trauma)
• Enrollment in a tocolytic study.