Methods
painful uterine contractions, rupture, cough
VAGINAL BLEEDING, WEST, PLACENTA PRAEVIA, VAGINA, PREMATURE RUPTURE OF MEMBRANES
This was a prospective cohort study conducted between 1st October 2020 and 31st October 2021 in the Department of Obstetrics and Gynaecology of Queen Mary Hospital, Hong Kong. TPTL was defined as symptoms of painful uterine contractions at preterm gestation as well as documented uterine activity on tocogram. Gestational age was assigned on the basis of the last menstrual period (LMP) and confirmed by ultrasonographic measurements in the first trimester. If there is a discrepancy, ultrasonographic estimated gestational age in the first trimester was used.Inclusion criteria included gestational age between 24 + 0 to 33 + 6 weeks, maternal age of ≥ 18 years old, intact membranes and cervical dilatation of ≤ 3 cm. Women were excluded if they had a prior fFN test performed or a history of tocolysis in the current pregnancy, premature rupture of membranes, multiple pregnancies, prior cervical examination or sexual intercourse within 24 h, moderate or heavy vaginal bleeding, cervical cerclage or placenta praevia. Women were given an information sheet about the study and the use of the fFN test. Written informed consent was signed and patients were enrolled under protocols approved by the Institutional Review Board of The University of Hong Kong/Hospital Authority Hong Kong West Cluster.During the gynaecological examination, a wet speculum with water as lubricant was introduced into the vagina. Women were asked to cough to look for any leaking of amniotic fluid through the cervical os. If rupture of membranes was diagnosed, women were excluded from the study. fFN testing was done before any digital or transvaginal ultrasound examination. A polyester swab was inserted into the posterior fornix and rotated for 10 s to absorb cervicovaginal secretion. The swab was then placed into the collection tube provided. One aliquot (200 µL) of the sample was analysed with the quantitative Perilynx analyser (Hologic) according to manufacturer’s instructions. The test result was concealed to the patients and the attending physician. Clinical management was at the discretion of the attending physician which included admission for tocolytics, intramuscular corticosteroids and magnesium sulphate as per hospital guidelines. Demographic data were obtained from each patient and extracted from medical records.Thresholds for fFN were used to determine sensitivity, specificity, PPV, and NPV for spontaneous delivery within 24 h, 48 h, 7 days and 14 days and delivery before 34 and 37 completed weeks of gestation. Results of fFN levels were then grouped into the 6 commonly used predefined incremental categories [