A woman aged 35 year with delayed cycles and a history of primary infeility. On laparoscopic examination she has a normal uterus with bilateral enlarged ovaries, normal fallopian tubes, chromotubation shows blue dye spillage. What is the most probable cause?

**Core Concept**
Polycystic ovary syndrome (PCOS) is a complex endocrine disorder characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries on ultrasound. The clinical presentation of delayed cycles and primary infertility in this patient is suggestive of PCOS.

**Why the Correct Answer is Right**
The patient's history of delayed cycles and primary infertility, combined with the laparoscopic findings of enlarged ovaries and normal fallopian tubes, is consistent with PCOS. The presence of polycystic ovaries is a key diagnostic criterion, and the normal fallopian tubes and chromotubation results rule out tubal factor infertility. The patient's symptoms are also consistent with hyperandrogenism, a common feature of PCOS.

**Why Each Wrong Option is Incorrect**
**Option A:** Endometriosis is typically characterized by pelvic pain, dysmenorrhea, and infertility due to adhesions and tubal damage, which is not consistent with this patient's presentation.

**Option C:** Ovarian cysts can cause pelvic pain and infertility, but they are not typically associated with delayed cycles and polycystic ovaries on ultrasound.

**Option D:** A tubo-ovarian mass is a type of ovarian tumor that can cause infertility, but it is not typically associated with delayed cycles and polycystic ovaries on ultrasound.

**Clinical Pearl / High-Yield Fact**
PCOS is a leading cause of infertility in women of reproductive age, and it is often associated with other metabolic disorders, such as insulin resistance and type 2 diabetes. Early diagnosis and treatment can improve fertility outcomes and reduce the risk of long-term complications.

✓ Correct Answer: B. PCOS

✓ Correct Answer: B. PCOS