Is Nextstellis a Progestin-Only Pill? Unpacking Its Unique Formulation
Nextstellis is definitively not a progestin-only pill (POP), also known as a minipill. It is a combined oral contraceptive (COC), meaning it contains two types of hormones: an estrogen and a progestin [1.3.6]. Specifically, each of the 24 active tablets in a Nextstellis pack contains 14.2 mg of estetrol (an estrogen) and 3 mg of drospirenone (a progestin) [1.4.2]. This unique combination sets it apart from the vast majority of other COCs on the market, which typically use a different estrogen called ethinyl estradiol (EE) [1.2.5].
The Components of Nextstellis: Estetrol (E4) and Drospirenone (DRSP)
The innovation of Nextstellis lies in its estrogen component, estetrol (E4). E4 is an estrogen that is naturally produced by the human fetal liver during pregnancy and can now be synthesized from a plant source for medical use [1.2.6, 1.6.4]. It is described as a Native Estrogen with Selective actions in Tissues (NEST), meaning it has a more targeted effect in the body compared to the synthetic estrogen EE [1.2.5, 1.9.2]. This selectivity is a key factor in its pharmacological profile, with studies suggesting it has a minimal impact on the liver, hemostasis (blood clotting), and breast tissue compared to other estrogens [1.6.3, 1.9.3].
The progestin component, drospirenone (DRSP), is a well-established synthetic progestin also found in other birth control pills like Yaz, Yasmin, and the progestin-only pill Slynd [1.3.1, 1.5.1]. Drospirenone's primary function in contraception is to prevent ovulation (the release of an egg from the ovary) [1.5.2]. It also thickens cervical mucus, making it harder for sperm to reach the uterus, and alters the uterine lining to reduce the likelihood of implantation [1.5.4]. Drospirenone is notable for its anti-androgenic and anti-mineralocorticoid properties, which can help mitigate side effects like acne and water retention [1.2.5, 1.5.6].
Understanding Progestin-Only Pills (POPs)
To fully appreciate the distinction, it's important to understand what a progestin-only pill is. As the name implies, POPs contain only one type of hormone: a progestin [1.5.2]. They work primarily by thickening cervical mucus and thinning the uterine lining. While some POPs, like those containing drospirenone (Slynd), can also reliably suppress ovulation, others do not always prevent it [1.5.2, 1.7.4]. POPs are often prescribed for individuals who cannot or should not take estrogen due to certain health conditions, such as a high risk of blood clots, being over 35 and a smoker, or while breastfeeding [1.3.4, 1.5.5].
Comparison: Nextstellis vs. Progestin-Only Pills (POPs)
Nextstellis and progestin-only pills differ significantly in their composition, mechanism of action, and potential user profile.
| Feature | Nextstellis (COC) | Progestin-Only Pill (POP) |
|---|---|---|
| Hormones | Estetrol (estrogen) and Drospirenone (progestin) [1.4.5] | A single progestin (e.g., drospirenone, norethindrone) [1.5.2, 1.7.4] |
| Primary Mechanism | Suppresses ovulation, thickens cervical mucus, thins endometrium [1.3.6, 1.9.2] | Primarily thickens cervical mucus and thins endometrium; may also suppress ovulation [1.5.2] |
| Estrogen Content | Yes (14.2 mg Estetrol) [1.4.2] | No estrogen [1.7.4] |
| Typical Regimen | 24 active (hormone) tablets and 4 inactive (placebo) tablets [1.4.6] | Typically 28 active hormone tablets (or 24 active and 4 inactive for drospirenone POPs) [1.5.2] |
| Bleeding Profile | Generally leads to predictable, scheduled withdrawal bleeding [1.8.4] | Often associated with irregular bleeding or spotting, which may decrease over time [1.5.2] |
| Key Benefits | High efficacy, good cycle control, potentially lower side effect profile due to E4 [1.8.2, 1.9.5] | Option for those with contraindications to estrogen (e.g., smokers over 35, high VTE risk) [1.3.4] |
| Common Side Effects | Bleeding irregularities, headache, breast symptoms, mood disturbances, acne, weight gain [1.2.6] | Irregular menstrual periods, acne, headache, breast tenderness, nausea [1.5.2] |
Efficacy, Safety, and Side Effects
Clinical trials have shown Nextstellis to be over 98% effective with perfect use [1.3.5]. Its unique estrogen, E4, is associated with a more favorable bleeding profile and a lower impact on triglycerides, cholesterol, glucose, and weight compared to EE-containing pills [1.2.5]. The risk of venous thromboembolism (VTE), a serious concern with COCs, may also be lower. The incidence of VTE in Nextstellis users is reported as 3.66 per 10,000 woman-years, compared to 5-10 per 10,000 for EE-containing COCs [1.2.1]. However, it is important to note that all COCs, including Nextstellis, carry a boxed warning regarding cigarette smoking and serious cardiovascular events, especially for women over 35 who smoke [1.2.6].
Conclusion
In conclusion, Nextstellis is not a progestin-only pill but a novel combined oral contraceptive that pairs the progestin drospirenone with a unique, plant-derived estrogen called estetrol (E4). This combination provides high contraceptive efficacy while offering a distinct safety and side effect profile, including good cycle control and a potentially lower impact on metabolic markers and blood clot risk compared to older formulations [1.2.5, 1.9.5]. Its development represents a significant step in hormonal contraception, providing a new option for individuals who may benefit from its selective tissue action and different risk-benefit balance.
For more detailed information, you can consult the official prescribing information on the FDA's website [1.8.3].
