What laboratory tests should be ordered for a woman in her 20s who has been trying to conceive for more than one year?

Laboratory Workup for a Woman in Her 20s with One Year of Infertility

For a woman in her 20s who has been trying to conceive for over one year, you should order: cycle day 21 serum progesterone to document ovulation, semen analysis for her partner, and TSH with prolactin levels. 1

Essential First-Line Laboratory Tests

The initial laboratory evaluation should be focused and cost-effective, targeting the most common causes of infertility 2, 1:

Ovulation Assessment

• Serum progesterone on cycle day 21 (or 7 days before expected menses if cycles are irregular) is the primary test to document ovulation 1, 3
• This single test confirms whether ovulation is occurring, which is critical since ovulatory dysfunction accounts for 21% of infertility cases 2

Hormonal Evaluation

• TSH (thyroid-stimulating hormone) - thyroid disorders can affect ovulation
• Prolactin level - hyperprolactinemia can cause anovulation
• These are standard screening tests mentioned across guidelines for reproductive-aged women with infertility 1, 3

Male Factor Assessment

• Semen analysis for the partner is mandatory, as male factors account for 26% of infertility cases 2, 1
• This should be done early in the evaluation since it's non-invasive and identifies a major contributor

Age-Specific Considerations

Since this patient is in her 20s (under 35 years), ovarian reserve testing is NOT routinely indicated 3. Tests like day 3 FSH, estradiol, and AMH are reserved for women over 35 years or those with specific risk factors for diminished ovarian reserve 3.

Additional Testing Based on Clinical Context

Consider adding these tests if specific risk factors are present 4:

• Hemoglobin A1c or fasting glucose if diabetes risk factors exist
• Rubella and varicella immunity if immunization status is unknown
• Chlamydia/gonorrhea screening if not recently tested or if risk factors present
• HIV, hepatitis B, and syphilis screening per routine preconception recommendations

Common Pitfalls to Avoid

• Don't order extensive hormonal panels initially - day 3 FSH/estradiol testing is unnecessary in women under 35 without risk factors 3
• Don't delay semen analysis - this is often overlooked but identifies problems in over one-quarter of couples 2
• Don't order anti-Müllerian hormone (AMH) routinely in young women without specific indications
• Avoid unnecessary tests like endometrial biopsy, which has no proven correlation with pregnancy outcomes 5

The Algorithmic Approach

1. First visit: Order cycle day 21 progesterone, TSH, prolactin, and arrange partner's semen analysis
2. If progesterone confirms ovulation and semen analysis is normal, proceed to structural evaluation (hysterosalpingography) 1
3. If anovulation is detected, additional hormonal workup may include LH, FSH, and androgens to evaluate for PCOS 2
4. If semen analysis is abnormal, repeat testing and consider male factor workup

The evidence strongly supports this focused approach rather than extensive "shotgun" testing, which increases costs without improving outcomes 5, 6. The goal is to identify treatable causes efficiently while avoiding exploitation of anxious couples with unnecessary procedures 5.