Despite considerable advances in recently developed combined oral contraceptives (COCs), resulting in lower rates of adverse events while maintaining contraceptive efficacy, there is interest in further innovation.
Estetrol (E4), a native oestrogen, and progestin drospirenone (DRSP) were combined in a new COC. A European expert panel reviewed the pharmacology, efficacy, and safety and tolerability of this combination. Their findings are presented as a narrative review.
E4 15mg/DRSP 3 mg in a 24/4 regimen provided effective contraception with good cycle control, characterised by a predictable regular bleeding pattern and minimal unscheduled bleeding, together with a good safety profile. The combination was associated with high user satisfaction, wellbeing, and minimal changes in body weight. The effects on endocrine and metabolic parameters were limited, and the combination was found to have a limited impact on liver function and lipid and carbohydrate metabolism. Moreover, its effect on several haemostatic parameters was lower than that of comparators containing ethinyl oestradiol (EE) 20mg/DRSP 3 mg and EE 30mg/levonorgestrel 150mg.
E4 15 mg/DRSP 3 mg provides safe and effective contraception, with high user satisfaction and predictable bleeding. Further research will evaluate the long-term safety of the COC.

UNASSIGNED: Despite considerable advances in recently developed combined oral contraceptives (COCs), resulting in lower rates of adverse events while maintaining contraceptive efficacy, there is interest in further innovation.
UNASSIGNED: Estetrol (E4), a native oestrogen, and progestin drospirenone (DRSP) were combined in a new COC. A European expert panel reviewed the pharmacology, efficacy, and safety and tolerability of this combination. Their findings are presented as a narrative review.
UNASSIGNED: E4 15 mg/DRSP 3 mg in a 24/4 regimen provided effective contraception with good cycle control, characterised by a predictable regular bleeding pattern and minimal unscheduled bleeding, together with a good safety profile. The combination was associated with high user satisfaction, well-being, and minimal changes in body weight. The effects on endocrine and metabolic parameters were limited, and the combination was found to have a limited impact on liver function and lipid and carbohydrate metabolism. Moreover, its effect on several haemostatic parameters was lower than that of comparators containing ethinyl oestradiol (EE) 20 µg/DRSP 3 mg and EE 30 µg/levonorgestrel 150 µg.
UNASSIGNED: E4 15 mg/DRSP 3 mg provides safe and effective contraception, with high user satisfaction and predictable bleeding. Further research will evaluate the long-term safety of the COC.

Estetrol/drospirenone is a combined oral contraceptive (COC) with a plant-synthesised foetal oestrogen (estetrol) and a well-established progestin (drospirenone). In preclinical models, estetrol has lower binding affinity for the oestrogen receptor-α (ER-α) in contrast to estradiol and has antagonistic properties against membrane ER-α in several tissues, including the breast, while retaining agonistic activity on receptors located in the nucleus. The low oestrogenicity of estetrol may potentially contribute to reduced thrombotic risk. Estetrol/drospirenone was an effective contraceptive in phase II and III clinical trials, with regular and predictable bleeding cycles maintained in the majority of women. Estetrol/drospirenone was generally well-tolerated with metrorrhagia reported as the most common treatment-related adverse event, which is consistent with other COCs. Cases of migraines with aura (or severe migraines), deep vein thrombosis, hyperkalaemia and depression were rarely reported during the phase III trials. Overall, estetrol/drospirenone is an effective and generally well-tolerated COC, with a potentially reduced risk of thrombosis.
In 2019, an estimated 44% of women aged 15–49 years worldwide used modern contraception methods, and in these women using modern methods, 18% used an oral contraceptive. Estetrol/drospirenone is a combined oral contraceptive (COC) which uses estetrol, a plant-synthesised oestrogen naturally produced by the human foetal liver during pregnancy, in combination with drospirenone, a well-known progestin. Combined, these hormones suppress ovulation, which constitutes their primary mode of action in preventing pregnancy. As estetrol has weaker oestrogen-related effects, it may potentially reduce the risk for blood clots. Estetrol/drospirenone was an effective contraceptive in clinical trials, and most women had regular and predictable bleeding cycles. Metrorrhagia (i.e. abnormal bleeding) was the most commonly reported treatment-related adverse effect; however, this is a common issue with hormonal contraceptives. Cases of severe migraine headaches, deep vein thrombosis, high potassium levels or depression were rarely reported during clinical trials. Estetrol/drospirenone is an effective oral contraceptive, which may offer a contraceptive option with a lower risk for blood clots. However, further research is required to confirm the reduced risk of clotting.

In this review paper, the existing information on the human fetal steroid estetrol (E4) has been summarized. In the past, E4 was considered as a weak estrogen and interest disappeared. However, recent new research has demonstrated that E4 is a potent, orally bioavailable, natural human fetal selective estrogen receptor modulator, since it acts in the rat as an estrogen on all tissues investigated except breast tumor tissue, where it has estrogen antagonistic properties in the presence of estradiol. Based on its safety data, its pharmacokinetic properties, its pharmacological profile and the results of first human studies, E4 may be suitable as a potential drug for human use in applications such as hormone replacement therapy (vaginal atrophy, hot flushes), contraception and osteoporosis. Additional areas worth exploring are the treatment of breast and prostate cancer, hypoactive sexual desire disorder and topical use (wrinkles) in women, auto-immune diseases, migraine, cardiovascular applications and the treatment of selected obstetric disorders.

Based on a review of the literature, this paper clarifies the pharmacologic properties of shortacting estrogens and their role in physiology and medicine. Shortacting estrogens display mixed agonist-antagonistic properties when injected in saline. The mixed estrogenic function results from the rapid clearance of these compounds from target tissue. When administered by pellet implant, however, shortacting estrogens act as full agonists. Both the uterotropic and vaginotropic response patterns of these compounds are detailed. Shortacting estrogens stimulate early uterotropic responses while having little effect on true uterine growth when administered by injection in saline. Thus, they have no antagonistic action when examined by shortterm uterotropic assays, but display partial antagonism when longterm uterine growth assays are used. Previous research has suggested that shortacting estrogens would not be effectual or antagonistic if present in a continuous fashion which would result in constant or longterm occupancy of the estrogen receptor. Estradiol, however, does manifest these properties when injected. Shortacting estrogens do not act as antagonists on vaginotropic responses as they do uterotropic responses. The paper also reviews the functions of these compounds in various physiological states, including blood binding, metabolism, menstruation, and pregnancy. Finally, clinical considerations are discussed. Estriol has an apparent selective effect on vaginotropic events. It has been effective in correcting symptoms of menopause, for example. However, estriol is not believed to have a protective effect against breast cancer. When it is present in a continuous fashion, estriol acts as an estrogen, thereby ruling out such an effect.