Should I wait to take progesterone until after my fertility lab testing is completed?

Progesterone and Fertility Testing: Timing Considerations

You should wait to take progesterone until after your fertility lab testing is completed to avoid interference with test results and ensure accurate diagnosis.

Impact of Progesterone on Fertility Testing

Progesterone can significantly affect the results of fertility testing by:

• Altering hormone levels that are typically measured during fertility evaluations
• Potentially masking underlying conditions that require diagnosis
• Interfering with the diagnostic accuracy of tests such as the progesterone challenge test

Progesterone Challenge Test Considerations

The progesterone challenge test is specifically used to evaluate women with amenorrhea by:

• Determining endometrial estrogen status
• Evaluating outflow tract patency
• Differentiating between functional hypothalamic amenorrhea and polycystic ovarian syndrome 1

Taking progesterone before this test would invalidate the results and compromise diagnostic accuracy.

Timing of Progesterone Administration

Proper timing of progesterone administration depends on its clinical purpose:

• For fertility testing: Complete all diagnostic tests first before starting progesterone
• For luteal phase support in ART: Progesterone is typically started after ovulation or oocyte retrieval 2
• For prevention of preterm birth: 17P is recommended from 16-20 weeks until 36 weeks in women with prior spontaneous preterm birth 2

Clinical Applications of Progesterone in Fertility Treatment

After fertility testing is complete, progesterone may be prescribed for:

1. Luteal phase support in assisted reproduction:

   • For FET (frozen embryo transfer) after PGT-M (preimplantation genetic testing)
   • Routine progesterone supplementation after ovulation or luteinization 2

2. Prevention of preterm birth:

   • 17P 250 mg IM weekly from 16-20 weeks until 36 weeks for women with singleton gestations and prior spontaneous preterm birth 2
   • Vaginal progesterone for women with short cervical length without prior preterm birth 2

Common Pitfalls to Avoid

• Premature progesterone use: Taking progesterone before fertility testing can lead to misdiagnosis or delayed diagnosis
• Incorrect interpretation of test results: Up to 60% of women with functional hypothalamic amenorrhea may still have withdrawal bleeding despite lower estrogen levels 1
• Relying solely on progesterone challenge test: Endometrial thickness measurement by ultrasound may be more reliable for assessing endometrial response 1

Recommendations for Specific Scenarios

• If undergoing fertility workup: Complete all diagnostic tests before starting any hormone therapy
• If planning assisted reproduction: Follow clinic protocols for progesterone timing, typically after ovulation confirmation
• If using progesterone for contraception: Timing is less critical for diagnostic purposes but should follow specific protocols 2

By waiting until after your fertility testing is completed to take progesterone, you ensure the most accurate diagnostic results and appropriate treatment planning for your specific situation.