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Contraception study in women: comparing oral drospirenone‑only, drospirenone + ethinylestradiol, and drospirenone + estetrol tablets

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What is this trial about?

A plain-language summary of the goals, design and what participants do

The trial looks at women who need birth control, called contraception, and compares three oral pill formulations. One pill contains the hormone drospirenone together with the newer estrogen estetrol, another combines drospirenone with the traditional estrogen ethinylestradiol, and a third contains only drospirenone without any estrogen.

The main purpose is to see whether the pill with estetrol and drospirenone has a smaller effect on blood clotting, measured by a laboratory test called endogenous thrombin potential, compared with the pill that uses ethinylestradiol and drospirenone, while the drospirenone‑only pill is expected to have little impact on clotting.

Participants will be assigned to take one of the three pills every day for about a year. They will attend routine visits, and at the end of the 12‑month period they will have a final check to assess how the medication affected the body. No additional procedures beyond the regular pill use and scheduled visits are required.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    First study visit

    After joining, attend the initial study visit where personal health information is recorded and basic laboratory tests are performed.

    During this visit, the study medication is assigned randomly to one of three groups.

  2. Step 2

    Receive study medication

    If assigned to the drspirenone‑only group, receive slinda 8 mg tablets containing only drospirenone.

    If assigned to the e4+drspirenone group, receive drovelis tablets that contain 3 mg drospirenone and 14.2 mg estetrol.

    If assigned to the ee20µg+drspirenone group, receive daylette tablets that contain 3 mg drospirenone and 0.02 mg ethinylestradiol.

    Each tablet is taken by mouth once daily, preferably at the same time each day.

  3. Step 3

    Daily medication intake

    Swallow one tablet with water; no food restrictions are required.

    Continue taking the assigned tablet every day for the entire 12‑month study period.

  4. Step 4

    Regular follow‑up visits

    Schedule visits at approximately 1 month, 3 months, 6 months, and 12 months after the first visit.

    At each visit, report any side effects, undergo brief physical examinations, and provide blood samples for laboratory analysis.

    The purpose of these visits is to monitor safety, assess how the medication affects blood clotting factors, and collect other health data.

  5. Step 5

    Final 12‑month visit

    After one year of daily tablet use, attend the endpoint visit.

    The final visit includes a comprehensive health assessment, laboratory tests to evaluate coagulation, and collection of study questionnaires.

    After this visit, no further study medication is required.

Who can join the trial?

8 criteria

  • Be a woman aged between 18 and 40 years when you join the study.
  • Agree to take the study medication and sign a written consent form that explains the research.
  • Have a body‑mass index (BMI) between 18 and 29.9. BMI is a measure that compares your weight to your height.
  • Be in good health, meaning you do not have any serious illnesses diagnosed by a doctor and you are not taking any ongoing medical treatments.
  • Have a regular menstrual cycle, which means your periods occur about the same way each month.
  • Wait at least two months after stopping any hormonal birth‑control pills or devices before starting the study medication.
  • Be at least three months past a pregnancy or breastfeeding period.
  • Be able to read and understand Finnish well enough to follow the study documents and talk with the study staff.

Who cannot join the trial?

5 criteria

  • Having a medical reason that makes using combined contraceptives unsafe (a “contraindication” means a condition that says you should not use that medication).
  • Having important problems found in the initial health tests or in an ultrasound picture (the ultrasound is a scan that uses sound waves to look at internal organs).
  • Smoking cigarettes or other nicotine products, using illegal (illicit) drugs, or drinking alcohol in a way that could be harmful (these habits can affect study results).
  • Planning to become pregnant while the study is happening (the study is not designed for people who want to get pregnant).
  • Having any other disease or health condition that could interfere with how the study is done or how the results are understood.
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Investigated drugs

  • Slinda

    is a birth control pill that contains only the hormone drospirenone. In this study it is used as the comparison group so researchers can see how a pill with drospirenone alone affects blood clotting tests. The goal is to understand the baseline effect of drospirenone without any added estrogen.

  • Drovelis

    is a combined oral contraceptive that includes drospirenone plus a newer type of estrogen called estetrol. This medication is one of the test groups. Researchers are looking at whether the combination of drospirenone with estetrol has a smaller impact on blood clotting than the traditional estrogen‑containing pill.

  • Daylette

    is another combined birth control pill that contains drospirenone together with the more common estrogen ethinylestradiol. It is also a test group in the trial. The study compares this standard combination to the estetrol‑based pill and to drospirenone alone to see how each affects clotting measures.

What is already known about the treatment

  • Slinda

    This medication is taken by mouth as a film‑coated tablet containing the progestin drospirenone. It is an approved prescription drug used for contraception and is listed in medical references as a progestin‑only pill. Drospirenone works by binding to progesterone receptors, preventing ovulation, and also blocks mineralocorticoid receptors, which can reduce water retention. It belongs to the pharmacological class of progestin‑only oral contraceptives.

  • Drovelis

    Drovelis is an oral film‑coated tablet that combines drospirenone with the natural estrogen estetrol. The product is commercially available and approved for use as a combined oral contraceptive. The drospirenone component blocks progesterone receptors to stop ovulation, while estetrol binds to estrogen receptors to support the uterine lining; together they provide reliable birth control. It is classified as a combined oral contraceptive containing a progestin and an estrogen.

  • Daylette

    Daylette is taken orally as a film‑coated tablet that includes drospirenone and ethinyl estradiol. It is a marketed combined oral contraceptive listed in standard drug references. Drospirenone prevents ovulation by acting on progesterone receptors, and ethinyl estradiol activates estrogen receptors to regulate the menstrual cycle; the combination ensures effective contraception. This medication falls under the class of combined hormonal contraceptives (progestin + estrogen).

Investigated diseases

Contraception - Contraception is the intentional prevention of pregnancy using various methods. It works by stopping the release of an egg, blocking sperm, or creating an environment that does not support fertilization. Over months of regular use, the chosen method continues to suppress the chance of conception as long as it is correctly applied. When a method is stopped, fertility typically returns to its previous state within a few weeks to several months, depending on the type used. The effectiveness of contraception can change if the method is missed, damaged, or interfered with by other substances.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-523359-71-00Protocol codeCoCo3Estimated enrolment156 patientsSponsorPohjois-Pohjanmaan hyvinvointialue

sourced from the EU Clinical Trials Register and site verification

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