Progesterone: what it does and how people use it

Progesterone is a natural hormone your body makes to regulate the menstrual cycle and support pregnancy. Doctors also prescribe it as a medicine—for hormone replacement, to help with fertility (luteal phase support), and to prevent preterm birth in some high-risk pregnancies. Knowing the different forms and common side effects helps you use it safely.

How progesterone works and when it helps

Progesterone prepares the uterus lining so an embryo can attach and grow. If levels drop too early, that can cause spotting or early pregnancy loss. In menopause, progesterone is often paired with estrogen to lower the risk of endometrial hyperplasia. For IVF or timed embryo transfers, doctors give progesterone to create the right uterine environment.

Common clinical uses include:

• Fertility care: luteal phase support after ovulation or IVF.
• Pregnancy support: sometimes given to women with a history of preterm labor or recurrent loss.
• Hormone therapy: combined with estrogen to protect the uterus in menopausal HRT.

Forms, dosing basics, and practical tips

Progesterone comes as oral pills (micronized progesterone), vaginal gels, suppositories, creams, and injections. The choice depends on why you need it and how well you tolerate each route. For fertility support, vaginal progesterone is common because it delivers the hormone directly to the uterus and often causes fewer systemic side effects. For menopause, oral or transdermal routes may be used.

Typical dose ranges (general examples, follow your clinician): oral micronized progesterone 100–400 mg nightly; vaginal pessaries or gels often given once or twice daily at doses set by the clinic; injectable progesterone is reserved for specific indications. Never change dose or stop suddenly without talking to your provider.

Side effects you might notice: tiredness, breast tenderness, bloating, mood swings, or spotting. Some people get drowsy with oral progesterone, so avoid driving until you know how it affects you. Serious reactions are rare but include severe allergic reaction or unusual bleeding—seek care if those happen.

Watch for drug interactions. Certain medicines that speed up liver enzymes (like some antiseizure drugs or rifampin) can lower progesterone levels, which may require dose changes. Always tell your provider about all prescriptions, supplements, and herbal products you use.

Storage and practical tips: keep pills and gels at room temperature away from heat. Vaginal inserts work better when placed at night before bed. If you miss a dose, follow your clinic’s instructions—don’t double up unless told to.

When to call your doctor: heavy vaginal bleeding, severe abdominal pain, signs of allergic reaction, sudden shortness of breath, or new severe headaches. If you're using progesterone for pregnancy support and have concerns about fetal movement or unusual symptoms, contact your obstetric team right away.

If you want help deciding which form is best for you, ask your clinician about side effects, convenience, and how each option fits your fertility or menopausal plan. Clear guidance makes using progesterone safer and more effective.