CBG Normalization After Discontinuation of COC's

Inclusion Criteria: * ≥18 years old * Using oral combined contraceptives of any kind and dosage * Planning to stop COC use shortly for at least 6 weeks (out of own reasons such as a pregnancy wish or choice for non-hormone based contraceptives) * COC use for at least 3 consecutive weeks before the discontinuation * Ability to provide informed consent * Ability to speak and understand Dutch Exclusion Criteria: * Switching to other hormonal contraceptives after taking the COC pill (e.g. progesterone containing contraceptives such as the Mirena IUD, contraceptive implants) directly after the discontinuations * Contra-indications to quit COC * Biological factors that affect CBG concentrations, including: * Illnesses interfering with CBG levels (severe liver or kidney disease, active malignancy, hyperthyroidism) * Use of insulin, systemic exogenous glucocorticoids, mitotane, selective estrogen receptor modulators (SERMs) * Pregnancy during study period after discontinuation of COCs