Development of breakthrough bleeding model of combined-oral contraceptives utilizing model-based meta-analysis

Area of Science:

• Pharmacology
• Reproductive Health
• Clinical Pharmacy

Background:

• Breakthrough bleeding (BTB) is a frequent adverse effect of hormonal contraception.
• Understanding BTB's relationship with combined oral contraceptive (COC) dosing is crucial for adherence.
• Existing data on progestin/ethinyl estradiol (EE) dose-response for BTB is limited.

Purpose of the Study:

• To establish dose-response relationships for COCs using BTB as a pharmacodynamic endpoint.
• To analyze BTB patterns across various progestin/EE combinations.
• To inform optimal COC regimen selection.

Main Methods:

• A model-based meta-analysis (MBMA) was conducted.
• Data from 25 studies on BTB were analyzed.
• Four progestins (desogestrel, drospirenone, gestodene, levonorgestrel) combined with EE at different doses were evaluated.

Main Results:

• BTB significantly increased upon COC initiation but decreased over time.
• The time for BTB to normalize depended on the EE dose.
• BTB returned to baseline within 3 months at 30 μg EE, but longer at 15-20 μg EE, regardless of progestin.

Conclusions:

• Established BTB dose-response relationships can guide optimal COC selection.
• Findings provide a basis for evaluating factors like drug interactions and demographics on BTB.
• EE dose is a key determinant in the resolution of BTB during COC use.