In a 29-year-old morbidly obese diabetic woman with irregular menstrual cycles every 3–4 months and a prolonged heavy bleed with clots lasting more than two weeks and a negative pregnancy test, what is the most likely diagnosis?

Chronic Anovulation (D)

The most likely diagnosis in this 29-year-old morbidly obese diabetic woman with irregular cycles every 3-4 months and prolonged heavy bleeding is chronic anovulation. 1, 2

Clinical Reasoning

The constellation of findings points definitively toward chronic anovulation:

• Irregular menstrual cycles every 3-4 months are a hallmark sign of anovulatory bleeding, distinguishing this from normal ovulatory cycles which occur every 21-35 days 2
• Prolonged heavy bleeding with large clots reflects anovulatory dysfunctional uterine bleeding caused by unopposed estrogen-driven endometrial proliferation without progesterone-mediated stabilization 2
• Morbid obesity and diabetes are well-established risk factors that predispose to chronic anovulation and polycystic ovary syndrome (PCOS), which affects 4-6% of reproductive-age women and is the leading cause of anovulatory infertility 2, 3
• Negative pregnancy test excludes pregnancy, the most common cause of amenorrhea 4

Why Other Diagnoses Are Less Likely

Fibroids (A) typically present with heavy menstrual bleeding but in the context of regular cycles, not the 3-4 month intervals seen here. While fibroids can coexist with anovulation, the irregular cycle pattern is the dominant feature pointing to hormonal dysfunction rather than structural pathology 1, 3

Bleeding disorder (B) would be expected to cause heavy bleeding from menarche onward and would affect all bleeding episodes (including minor trauma), not just menstrual bleeding with this specific pattern of oligomenorrhea 1

Incomplete abortion (C) is excluded by the negative pregnancy test and the history of irregular cycles predating this bleeding episode 1

Pathophysiology

Excess adipose tissue in morbidly obese patients increases peripheral aromatization of androgens to estrogen, resulting in chronic unopposed estrogen stimulation of the endometrium 2. This hormonal milieu leads to continuous endometrial proliferation without progesterone-mediated stabilization, producing irregular breakdown and unpredictable heavy bleeding 2. The PALM-COEIN classification system identifies ovulatory dysfunction as a nonstructural cause of abnormal uterine bleeding, often associated with heavy, irregular bleeding 1

Critical Next Steps

Endometrial sampling (biopsy) is mandatory in this patient despite her young age, because obesity and diabetes combined with chronic anovulation create a synergistic risk for endometrial hyperplasia and malignancy from persistent unopposed estrogen exposure 2. The standard age threshold of >45 years for endometrial biopsy should be lowered in patients with these metabolic risk factors 2

Additional initial workup should include:

• TSH and prolactin levels to exclude thyroid dysfunction and hyperprolactinemia as alternative causes of anovulation 1, 2
• Transvaginal ultrasound to assess endometrial thickness and exclude structural pathology 1
• Consider androgen profile (testosterone, DHEA-S) if clinical hyperandrogenism is present 2

Common Pitfall

Do not initiate hormonal therapy before excluding endometrial hyperplasia or malignancy through tissue diagnosis, given the heightened cancer risk conferred by the combination of obesity, diabetes, and chronic anovulation 2. The unopposed estrogen state in chronic anovulation markedly increases the risk of endometrial adenocarcinoma 4