PartoSure to Predict Spontaneous Preterm Delivery in Pregnancies After Assisted Reproductive Technology (ART)

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.