A 32-year-old woman presents with primary infertility of 3 years' duration. She has regular menstrual cycles, normal BMI, and no pelvic pain. Her partner has normal semen analysis. Investigations reveal normal FSH, LH, and prolactin levels. Hysterosalpingography shows patent fallopian tubes with normal uterine cavity. Which of the following is NOT a recognized cause of female infertility in this clinical scenario?

Explanation

## Analysis of Female Infertility Causes ### Clinical Context The patient has: - Regular ovulatory cycles (normal FSH/LH) - Patent tubes and normal uterine cavity - Normal partner semen analysis - Normal prolactin already documented This narrows the differential to **ovulatory dysfunction, tubal/peritoneal factors, and cervical factors**. ### Recognized Causes in This Scenario **Key Point:** In a woman with normal hormonal profile and patent tubes, the following remain valid causes of infertility: | Cause | Mechanism | Diagnostic Finding | |-------|-----------|--------------------| | Antisperm antibodies | Immune-mediated sperm immobilization | Positive MAR test or immunobead test | | Luteal phase defect | Inadequate progesterone secretion | Serum progesterone <10 ng/mL on day 21 | | Endometriosis | Peritoneal inflammation, adhesions, altered ovulation | Laparoscopic visualization | | Elevated prolactin | Suppresses GnRH → anovulation | Serum prolactin >100 ng/mL | ### Why Option 4 is Incorrect **High-Yield:** The stem explicitly states that prolactin is **already normal** in this patient. Elevated prolactin (>100 ng/mL with galactorrhea) would be inconsistent with the documented normal prolactin level and regular menstrual cycles. This option contradicts the clinical data provided. **Clinical Pearl:** Hyperprolactinemia typically presents with: - Oligomenorrhea or amenorrhea (not regular cycles) - Galactorrhea - Elevated serum prolactin on biochemistry Since all three are absent in this case, hyperprolactinemia cannot be the cause. ### Why Options 1, 2, 3 Remain Valid **Option 1 (Antisperm antibodies):** Cervical factor infertility due to antisperm antibodies is a recognized cause, especially when semen analysis is normal but cervical mucus shows poor sperm penetration. **Option 2 (Luteal phase defect):** Although controversial, progesterone <10 ng/mL in the luteal phase is still cited as a potential cause in some guidelines, particularly in women with recurrent pregnancy loss. **Option 3 (Endometriosis):** A leading cause of infertility in women with normal ovulation and patent tubes; causes peritoneal inflammation and adhesions that impair fertility.