Diagnostic Tests in the Context of Threatened Preterm Labour (PREMAQUICK)

Combined Detection of Interleukin-6 and Insulin-like Growth Factor Binding Protein-1 Total and Native (Premaquick) for the Prediction of Delivery in Women With Threatened Preterm Labor

The primary purpose of the protocol is to compare the diagnostic accuracy in terms of positive and negative predictive values of Premaquick © (combined detection of IL-6 / IGFBP-1 total / IGFBP-1 native) and Quikcheck fFN ™ (fibronectin detection) tests for prediction of spontaneous delivery within 7 days in women with threatened preterm labor. The study hypothesis is that combined detection of IL-6 / IGFBP-1 total / IGFBP-1 native dice the admission will improve the prediction of delivery compared to the detection of fetal fibronectin alone in women with threatened preterm labor.

The threat of premature labour is the main cause of hospitalization during pregnancy (38% of hospitalizations). To date, the assessment of severity relies mainly on ultrasound measurement of the cervix. The length of the cervix is significantly correlated with the risk of spontaneous premature delivery. A threshold of 25mm is relevant to rule out a delivery within 7 days but the identification of new markers including biological would be interesting to guide the clinician in assessing the risk of preterm birth. Among the biomarkers measured in vaginal secretions, the detection of fetal fibronectin seems to be the most relevant because of a high negative predictive value (NPV) up to 100% to rule out a delivery within 7 days. However, the use of this test is discussed because of its low positive predictive value (PPV) to predict delivery within 7 days (from 11% to 48%). The use of Premaquick © test (Biosynex, Strasbourg, France), which allow the simultaneous quantification of IL-6, total IGFBP-1 and native IGFBP-1 could be more efficient compared to the detection of fibronectin by improving the VPP. The results already obtained on a cohort of 97 patients (Eleje et al., 2016) show a similar NPV and a higher PPV of the Premaquick© test compared to the Quikcheck fFN ™ test (PPV up to 95% when the 3 markers are positive). Investigator wish to conduct a comparative study between these two tests on a larger cohort of patients (n = 220). Results of the tests will be masked for the clinician and the patient in order to assess and compare their ability to predict delivery within 7 days without modify the current medical management.

PREMAQUICK® is a rapid multiparametric test which aim to detect the presence of IGFBP-1 (Insulin-like Growth Factor-Binding Protein 1), fragmented IGFBP-1 and IL-6 (Interleukin 6) in vaginal secretions. By combining biomarkers of myometrial activation, cervical maturity and inflammation / infection, PREMAQUICK® integrates the main pathogenic mechanisms responsible for premature delivery, which makes it possible to predict or, on the contrary, rule out the risk of childbirth within 7 to 14 days. This test is intended for in vitro diagnostic use. Vaginal secretions are collected under speculum with a swab (10 seconds of impregnation of the swab). The swab is immersed in a tube containing an extraction buffer for 10 seconds. The tube is mixed and then 3 drops are deposited in each wells of the test device for 10 minutes. Visual reading should be done between 10 and 15 minutes.

- The Hologic QuikCheck fFN test is intended to be used for the qualitative detection of fetal fibronectin in cervicovaginal secretions. The presence of fetal fibronectin in cervicovaginal secretions between 22 weeks, 0 days and 34 weeks, 6 days of gestation is associated with elevated risk of preterm delivery. Quick Check fFN test® is a 10 min, one-step, visual test consists of a sterile polyester-tipped applicator, fetal fibronectin test strip, and sample extraction buffer. The QuikCheck fFN is a solid-phase immunogold assay which aim to detect fetal fibronectin. A positive specimen will result in two visible lines and a negative specimen will result in one visible line (control).

Diagnostic value of Premaquick and Quikcheck fFN ™ tests to predict delivery within 7 days (yes / no).

The results (positive / negative) of the Premaquick and Quikcheck fFN ™ tests and the delay between the test and delivery time (in days) will allow to determine the PPV and NPV of the tests to predict delivery within 7 days.

Results of the tests are given by the biochemistry department after a minimum of 15 days after the tests have been performed. The date of delivery is obtained by analyzing the patient file.

Inclusion Criteria: Major pregnant women admitted to Clermont-Ferrand CHU maternity for threatened preterm delivery with intact membranes between 24 and 34 (+6 days) week of amenorrhea, with length of cervix < 30mm (ultrasound measurement). Ability to give informed consent. French social security scheme. Exclusion Criteria: - Dilation of the cervix ≥ 4 cm Triple pregnancy or more Fetal membranes rupture Known uterine malformation Hydramnios Fetal malformation Placenta previa Abundant metrorrhagia Patient who had already participated in the study during the same pregnancy Patient under guardianship or curatorship

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