Menstrual function and luteal-phase deficiency in relation to weight changes and dieting

It is evident that decreased nutrition may negatively affect ovarian function. If reduced food intake results in a weight below the normal range, ovarian function is reduced virtually without exception, and amenorrhea ensues. Although normal weight is a prerequisite for normal ovarian function, it does not exclude nutrition-induced disturbance. Because body weight is defended by physiologic mechanisms reducing energy expenditure, sizable reductions in caloric intake result only in small weight changes; reductions of approximately 20% may even be fully compensated. Normal-weight bulimic patients have a high rate of menstrual disturbance including luteal-phase disturbance and amenorrhea. In the light of the finding that otherwise healthy normal-weight young women have a high rate of menstrual dysfunction during a 1,000-Cal diet of a few weeks' duration, there is no need to attribute this finding to potential effects of psychopathology, disease stress, or associated affective disorder. The pattern of intermittent starvation observed in these patient may be a sufficient explanation. For resumption of normal reproductive function not only cessation of binge eating, but reestablishment of normal eating behavior (in a global sense) is important. The effects of dieting on reproductive endocrine function in otherwise healthy women were marked but not homogeneous. Not all women that diet at normal weight are affected by menstrual disturbance. The risk is modulated by other factors, such as age. Because the mediating mechanisms are not precisely known, in the individual woman a causal relationship between dieting and ovarian dysfunction cannot be demonstrated positively at present. However, it seems to be an important complement to diagnosis and treatment in reproductive endocrinology to assess eating behavior in patients with functional hypothalamic amenorrhea, disturbed follicular development, and luteal-phase defects and to advise these women of the possibility that their state is caused or aggravated by restrained eating or other forms of chronic or intermittent reduction of food intake.