Safety of estetrol (E4) combined with drospirenone (DRSP) birth control
International Active Surveillance Study: Safety of Estrogen Estetrol (E4) Contraceptive Study (INAS-SEECS)
This study will test whether a birth control pill combining estetrol (E4) and drospirenone (DRSP) has similar risks of blood clots compared with other commonly used combined oral contraceptives in women of reproductive age.
Quick facts
| Study type | Observational |
|---|---|
| Enrollment | 68100 (estimated) |
| Sex | Female |
| Sponsor | Center for Epidemiology and Health Research, Germany Academic / other |
| Locations | 1 site (Berlin, State of Berlin) |
| Trial ID | NCT06186271 on ClinicalTrials.gov |
What this trial studies
This is an international observational post‑marketing safety study comparing new users of the estetrol/drospirenone (E4/DRSP) oral contraceptive with new users of EE/DRSP and with a pooled cohort of EE/LNG, EE/NETA, and EE/NGM users. The main clinical outcomes are venous thromboembolism (VTE) and arterial thromboembolism (ATE), measured in routine clinical practice across participating sites. The study enrolls new users, includes an adequate number of obese women for subgroup analyses, and is sized to rule out a two‑fold increase in VTE risk for the primary comparisons. It is being conducted to meet FDA post‑market requirements and is coordinated by the Center for Epidemiology and Health Research in Germany.
Who should consider this trial
Good fit: Women of reproductive age who are new users of combined oral contraceptives—specifically those starting E4/DRSP, EE/DRSP, or EE combined with levonorgestrel, norethisterone/NETA, or norgestimate—are the intended participants.
Not a fit: Women who are not starting one of these combined oral pills, those who gave birth within the past six weeks, or users of non‑combined or non‑oral contraceptives are unlikely to benefit from joining.
Why it matters
Potential benefit: If successful, the results could reassure patients and clinicians that E4/DRSP does not carry a higher risk of blood clots than other combined oral contraceptives, expanding safe contraceptive choices.
How similar studies have performed: Early clinical trials and laboratory data indicated E4/DRSP may have less impact on hepatic parameters and hemostasis than EE combinations, and E4/DRSP has regulatory approval in several regions, but large real‑world comparative safety data on clotting risks remain limited.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: • New users of E4/DRSP or EE/DRSP or EE/LNG or EE/NGM or EE/NETA Exclusion Criteria: • Women who have given birth six weeks before treatment starts will be excluded from the study.
Where this trial is running
Berlin, State of Berlin
- Berlin Center for Epidemiology and Health Research — Berlin, State of Berlin, Germany (Recruiting)
Study contacts
- Principal investigator: Klaas Heinemann, Dr. — ZEG Berlin GmbH
- Study coordinator: Armin Papkalla, Dr.
- Email: a.papkalla@zeg-berlin.de
- Phone: +49 30 945 101 20
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.