Progestogens Classification and Uses
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Direct answer
Progestogens are natural progesterone or synthetic progestins, and synthetic progestins are grouped by chemical structure into 19-nortestosterone, 17-hydroxyprogesterone and spironolactone-derived agents. Their androgenic profile varies: levonorgestrel and norethisterone are androgenic, while drospirenone and cyproterone acetate are antiandrogenic. Clinically they are used for contraception, endometrial protection alongside oestrogen, abnormal uterine bleeding, secondary amenorrhoea and endometriosis.
What you must remember
- Natural progesterone: micronised progesterone, structurally identical to the endogenous hormone, neutral in androgenic effect; used for luteal support and vaginal use in short cervix.
- 19-nortestosterone derivatives: levonorgestrel and norethisterone, the most androgenic group, causing acne, hirsutism and weight gain.
- 17-hydroxyprogesterone derivatives: medroxyprogesterone acetate for depot contraception and endometrial protection; cyproterone acetate is antiandrogenic.
- Spironolactone-derived: drospirenone, with antimineralocorticoid and antiandrogenic actions, used in combined pills.
- Dienogest: a 19-nortestosterone derivative with low androgenicity, commonly used in endometriosis.
- Endometrial protection: a progestogen must be added to oestrogen in women with a uterus to prevent endometrial hyperplasia.
- Adverse effects: breakthrough bleeding, mood change, weight gain, and dyslipidaemia, with androgenic effects greatest in the 19-nortestosterone group.
Matching the progestogen to the patient
A 27-year-old with PCOS wants contraception that also improves acne and hirsutism, so the androgenic profile decides the choice. The table groups the commonly used progestogens by structure and profile.
| Class | Example | Androgenic profile | Typical use |
|---|---|---|---|
| Natural | Micronised progesterone | Neutral | Luteal support, short cervix |
| 19-nortestosterone | Levonorgestrel, norethisterone | Androgenic | Contraception, abnormal uterine bleeding |
| 19-nortestosterone | Dienogest | Low androgenicity | Endometriosis |
| 17-hydroxyprogesterone | Medroxyprogesterone acetate | Low to moderate | Depot contraception, endometrial protection |
| Spironolactone-derived | Drospirenone | Antiandrogenic | Combined pill, acne |
Androgenic progestins worsen acne and hirsutism, so antiandrogenic options suit PCOS. Dienogest is commonly chosen in endometriosis because its androgenic effects are low. The androgenic rating is a relative guide, not an absolute property. Progestin choice in a vignette therefore starts with the patient's androgen-related symptoms, then moves to the indication, since the same molecule can help one woman and worsen another's skin or hair.
Where the exam tries to catch you
Progestogen questions usually test the androgenic profile and the reason progestogen is ever added.
- Trap: prescribing levonorgestrel to a woman with acne and hirsutism Correct: an antiandrogenic progestogen, such as drospirenone or cyproterone acetate, suits her better.
- Trap: treating all progestogens as interchangeable Correct: chemical structure drives the androgenic profile, so the class determines side effects.
- Trap: stopping progestogen when oestrogen is started in a woman with an intact uterus Correct: unopposed oestrogen raises endometrial hyperplasia risk, so progestogen must continue.
Frequently asked questions
What is the difference between natural progesterone and synthetic progestins?
Natural progesterone is structurally identical to the endogenous hormone, while synthetic progestins are altered molecules with varied receptor and androgenic activity. Micronised progesterone is preferred for luteal support because of its neutral profile. Synthetic progestins are chosen for contraception or bleeding control.
Which progestogen is the most androgenic?
Levonorgestrel is among the most androgenic progestogens, and norethisterone is also androgenic. These agents can cause acne, hirsutism, oily skin and weight gain. Antiandrogenic options such as drospirenone or cyproterone acetate suit women with PCOS.
Why is a progestogen added to oestrogen in hormone therapy?
A progestogen is added to oestrogen in women with an intact uterus to prevent endometrial hyperplasia and carcinoma. Unopposed oestrogen stimulates endometrial growth. Women who have had a hysterectomy do not need the progestogen.
Which progestogen is used for luteal phase support in IVF?
Micronised progesterone, given vaginally or intramuscularly, is commonly used for luteal phase support in IVF. Its neutral androgenic profile suits the endometrium. Dose and route follow the local protocol.
What is medroxyprogesterone acetate used for?
Medroxyprogesterone acetate is used as a depot injectable contraceptive given every three months, and for endometrial protection and secondary amenorrhoea. Its androgenic profile is low to moderate. Bone density effects are a key counselling point during long-term use.