Is 200mg of progesterone (a hormone) effective for ovulation suppression?

Efficacy of 200mg Progesterone for Ovulation Suppression

200mg of progesterone is not effective as a standalone method for reliable ovulation suppression. According to CDC guidelines, at least seven days of continuous hormonal contraceptive use is necessary to reliably prevent ovulation 1.

Evidence for Progesterone in Ovulation Suppression

The efficacy of progesterone for ovulation suppression depends on several factors:

• Dosage considerations: While 200mg of micronized progesterone is commonly used for hormone replacement therapy for 12-14 days per cycle, this dosing is not established for reliable ovulation suppression 1.

• Route of administration: The effectiveness varies significantly based on administration route:

  • Oral progesterone undergoes >90% first-pass metabolism, limiting efficacy of once-daily administration 2
  • Vaginal administration of 200mg or 400mg progesterone every 12 hours can achieve and maintain physiological serum progesterone levels similar to midluteal phase 3

• Duration of use: Single or short-term progesterone administration is insufficient for reliable contraception. The CDC indicates seven continuous days of hormonal contraceptive use is the minimum needed 1.

Clinical Applications of Progesterone

Progesterone at 200mg dosing has established efficacy in specific clinical scenarios:

• Preterm birth prevention: 200mg vaginal progesterone suppository daily is recommended for singleton pregnancies without prior spontaneous preterm birth but with short cervical length (≤20mm) diagnosed before 24 weeks gestation 4.

• Hormone replacement therapy: 200mg is commonly used for 12-14 days per cycle or continuously 1.

• NOT recommended for contraception: Unlike combined hormonal contraceptives that contain both estrogen and progestin components specifically designed to inhibit ovulation, natural progesterone alone at 200mg is not established as an effective contraceptive 5.

Pitfalls and Considerations

• Incomplete ovulation suppression: Progesterone alone, particularly at 200mg dosing, may not consistently block follicular development and ovulation 5.

• Formulation matters: Vaginal progesterone in wax-based suppositories provides slower release and more sustained levels compared to other formulations 3.

• Side effects: Continuous progesterone administration may contribute to depressive symptoms in some women 1.

• Monitoring challenges: Without reliable ovulation suppression, there's risk of breakthrough ovulation and unintended pregnancy if used for contraceptive purposes.

Alternative Approaches

For more reliable ovulation suppression:

• Combined hormonal contraceptives: These contain both estrogen and progestin components that work synergistically to inhibit ovulation 5.

• Synthetic progestins: These are specifically designed to resist enzymatic degradation and remain active after oral administration, providing more reliable contraceptive efficacy than natural progesterone 2.

• Progesterone antagonists: Daily administration of progesterone antagonists like mifepristone (at 2mg or 5mg) has shown to inhibit ovulation in 90-95% of cycles and induce amenorrhea in the majority of women 6.

In conclusion, while 200mg of progesterone has established uses in specific clinical scenarios like preterm birth prevention, it is not recommended as a reliable method for ovulation suppression when contraception is the primary goal.