Is fasting a suitable treatment approach for a woman with Polycystic Ovary Syndrome (PCOS) who may also have hypothalamic amenorrhea?

Fasting is Contraindicated in Hypothalamic Amenorrhea, Even with PCOS Features

Fasting is contraindicated in women with functional hypothalamic amenorrhea (FHA), regardless of whether they have polycystic ovarian morphology (PCOM) features, as it would worsen the underlying energy deficit that causes FHA and potentially exacerbate health consequences. 1, 2

Understanding the Relationship Between FHA and PCOM

• FHA is characterized by cessation of menstrual cycles due to energy deficit, excessive exercise, or stress, resulting in suppressed gonadotropin-releasing hormone (GnRH) secretion 3
• Up to 43% of women with FHA may have polycystic ovarian morphology (PCOM) or "PCO-like abnormalities" 1
• Some women with FHA-PCOM may have elevated anti-Müllerian hormone levels and increased ovarian volume, suggesting a potential link between FHA and PCOS 4
• Despite PCOM features, the primary diagnosis remains FHA if there are clear signs of energy deficiency and estrogen deficiency 1

Why Fasting is Harmful in FHA

• Energy availability below the threshold of 30 kcal/kg fat-free mass/day inhibits LH pulsation and causes menstrual disorders 2
• Fasting would further decrease energy availability, which is already compromised in FHA 2
• The Endocrine Society guidelines emphasize that addressing energy deficit is crucial for FHA recovery 1
• Regular meals providing adequate glucose are essential, as glucose affects LH pulses and thyroid hormone (T3) and cortisol concentrations 2

Diagnostic Differentiation Between FHA and PCOS

• FHA typically presents with low estrogen levels, absent response to progestogen challenge, and low-normal gonadotropin levels 4
• LH:FSH ratio <1 is found in about 82% of FHA patients, while PCOS typically shows LH:FSH ratio >2 1
• Endometrial thickness is a good indicator of estrogen status; thin endometrium suggests FHA 1
• Presence of typical causes of FHA (excessive exercise, underweight, caloric deficiency, stress) alongside signs of estrogen deficiency strongly supports an FHA diagnosis 1

Proper Management Approach for FHA

• Dietary intervention should focus on increasing caloric intake to restore energy balance 2
• An increase in body fat percentage above 22% may be required to restore menstrual function 2
• Even a modest increase in body fat mass of one kilogram increases the likelihood of menstruation by 8% 2
• The Endocrine Society recommends that women with FHA should have a BMI ≥18.5 kg/m² before considering ovulation induction 1
• Reducing exercise intensity or training volume is advisable, though complete cessation of physical activity is not necessary 2

Long-term Health Considerations

• FHA is associated with bone health deterioration, with a 2-fold increased risk of fractures compared to healthy women 1
• Hormone replacement therapy (preferably transdermal estradiol with cyclic oral progestin) is recommended over combined oral contraceptives to protect bone health 1
• Combined oral contraceptives inhibit IGF-1 production via first-pass hepatic metabolism, potentially decreasing osteoblastic activity 1
• Baseline bone mineral density measurement is recommended in those with at least 6 months of amenorrhea 1

Special Considerations for FHA-PCOM

• Despite PCOM features, the primary treatment approach should still address the energy deficit 1
• Studies show that after recovery from FHA, many women with PCOM features see decreases in AMH, androgens, and ovarian volume 1
• Only a small percentage of women with FHA-PCOM develop true PCOS after recovery 1
• For fertility concerns, pulsatile GnRH therapy has shown similar effectiveness in both FHA and FHA-PCOM patients 5

In conclusion, regardless of PCOS-like features, the primary approach must address the energy deficit in FHA, making fasting counterproductive and potentially harmful to recovery and long-term health outcomes.