A new progestin-only pill (POP): the impact of drospirenone-only pill 4 mg 24 + 4 on coagulation markers and bleeding patterns.

Purpose: Progestin-only pills (POPs), compared to combined, are not associated with an increased risk of venous thromboembolism, but are associated with a poor cycle control. The aim of this study was to evaluate the impact of a new POP [4 mg drospirenone (DRSP) for 24 days with a 4-day hormone-free interval] on some coagulation markers (both procoagulant and fibrinolytic) and to describe its impact on bleeding patterns.

Materials and methods: This is a prospective trial, based on serum evaluation of following coagulation markers and tests: Factor (F) X, F VIII, F V, INR, aPTT, Protein S and antithrombin III. A 'bleeding diary' was used to categorise women as having (1) unscheduled bleeding, (2) scheduled bleeding and (3) amenorrhoea. Thirty patients were followed for six 28-day intake cycles, with a follow-up at the end of the 3rd and 6th cycles.

Results: There was a significant decrease of F X (p = 0.03) (-5.7% at cycle 6). No significant changes have been observed for F VII, F V and INR. A significant increase in aPTT (p = 0.01 at 3 cycles), Protein S (p = 0.0006 at 3 cycles) and antithrombin III (p < 0.0001 at 3 cycles) was recorded. This non-deteriorating coagulation impact was associated with a significant and progressive reduction of days of scheduled and unscheduled bleeding in users between cycles 4 and 6 (from 1.3 ± 0.2 days at cycle 4 to 0.8 ± 0.1 days at cycle 6 and from 2.6 ± 0.4 days at cycle 4 to 0.6 ± 0.2 days at cycle 6, respectively, p < 0.0001).

Conclusions: DRSP 24 + 4 use was associated with a non-deteriorating effect on coagulation markers and a significant progressive reduction of days of scheduled and unscheduled bleeding.