A 28-year-old woman presents with primary infertility of 3 years duration. Her menstrual cycles are regular (28 days), and she has no dysmenorrhea or pelvic pain. Husband's semen analysis is normal. What is the most common cause of female infertility in this clinical scenario?

Explanation

## Overview of Female Infertility Causes Tubal factor infertility accounts for approximately 25–35% of all female infertility cases, making it the **most common identifiable cause** of female infertility globally. ### Epidemiology of Female Infertility Causes | Cause | Frequency (%) | Key Features | |-------|---------------|---------------| | **Tubal factor** | 25–35 | Most common; includes obstruction, stricture, adhesions | | Ovulatory dysfunction | 20–25 | Regular cycles do NOT exclude ovulation disorders | | Uterine/endometrial | 10–15 | Fibroids, polyps, asherman syndrome | | Cervical factor | 5–10 | Least common; hostile mucus, stenosis | | Unexplained | 10–15 | No identifiable cause despite normal workup | ### Why Tubal Factor Is Most Common **Key Point:** Tubal damage results from: - Pelvic inflammatory disease (PID) — most common cause of tubal damage - Previous pelvic/abdominal surgery (appendectomy, cesarean, myomectomy) - Endometriosis with adhesion formation - Tuberculosis (especially in endemic regions like India) - Intrauterine adhesions (Asherman syndrome) affecting tubal patency ### Clinical Clues in This Case **High-Yield:** The patient has: - Regular menstrual cycles → **ovulation is likely occurring** (excludes ovulatory dysfunction as primary diagnosis) - No dysmenorrhea or pelvic pain → **lower likelihood of endometriosis**, but does NOT exclude tubal pathology - Normal male factor → **female factor must be investigated** - No mention of vaginal discharge or cervicitis → **cervical factor less likely** **Clinical Pearl:** Regular menstruation does NOT guarantee normal ovulation or tubal patency. Tubal obstruction can coexist with completely normal cycles. ### Diagnostic Approach The next step would be: 1. Confirm ovulation (serum progesterone day 21, LH surge, follicle tracking) 2. **Assess tubal patency** (HSG or laparoscopy with dye test) 3. Evaluate uterine cavity (sonohysterography if HSG abnormal) **Mnemonic: TUBE** — **T**ubal (most common), **U**terine, **B**ovulatory, **E**ndometrial/cervical (least common in that order of frequency) [cite:Jeffcoate's Principles of Gynaecology 8e Ch 19]