Comparison of PAMG-1 and phIGFBP-1 Tests for the Prediction of Preterm Delivery in Patients with Preterm Labor

Abstract

Objective: To compare PAMG-1 and phIGFBP-1 tests in predicting impending spontaneous preterm delivery within 7 days upon presentation in pregnant women with symptoms of preterm labor. Study Design: From September 2014 to April 2015 women with singleton gestation, symptoms of preterm labor, GA 22 - 35, participated in this prospective cohort study upon admission. Recruited patients had intact membranes and a minimal cervical dilatation of ≤3 cm. Vaginal swabs for phIGFBP-1 and PAMG-1 were taken in addition to routine treatment. Biochemical test results were blinded and had no effect on management of patients. Results: A total of 96 patients were screened for inclusion into the trial; 57 met the inclusion criteria for final analysis. The PAMG-1 test was positive in 5.7% of patients, while phIGFBP-1 test was positive in 29.8% of patients. The prediction of spontaneous preterm delivery within 7 days of admission in patients with a cervical length < 25 mm (30%), the PAMG-1 test and phIGFBP-1 test showed a SN of 100% and 100%; SP of 83.3% and 50.0%, (p ≤ 0.05); PPV of 71.4% and 45.5%; and NPV of 100% and 100%. 89.5% of women who received corticosteroids and 84.2% of women who received tocolysis did not go into preterm labor within one week. Conclusion: Our study supports the high negative predictability of biochemical tests to rule out spontaneous preterm labor in patients with a short cervix. However, our study strongly suggests that the PAMG-1 test is more accurate for predicting imminent spontaneous preterm delivery as compared to phIGFBP-1. These findings can significantly reduce economic burden caused by unnecessary admission and treatment of patients suspected of preterm labor. Such a reduction in the use of corticosteroids and tocolytics would lead to a reduction in the short and long term health effects associated with the use of therapeutic drugs like corticosteroids, antibiotics and tocolytics.