Endovaginal ultrasound is currently the gold standard to diagnose a shorted cervical length and, by extension, assess the risk of preterm labor. The major inconvenient is that this is an invasive method of diagnosis that tends to be poorly accepted by some patients. This study aims to evaluate the accuracy of a noninvasive transperineal ultrasound cervical measurement in comparison to the endovaginal technic in 2nd and 3nd trimester pregnant women where a cervical ultrasound is indicated.

The cervical length is a crucial part of the diagnostic of premature labor. The gold standard technic is the endovaginal ultrasound. This is a technic with good reproducibility and good precision. Some authors have found the transperineal technic to present the same characteristics, without being as invasive. The aim of the study was to compare the results of the less invasive technic to the current invasive gold standard in pregnant women who consult for contraction, or for whom cervical modification is suspected in order to determine whether the former could replace the latter.

Inclusion Criteria:

• Pregnant women between 2nd and 3rd trimester consulting in obstetric emergency for whom a cervical ultrasound is indicated

Exclusion Criteria:

• minor patients
• mentally deficient persons