Predicting the Return of Menses

The weight required for return of menses is highly variable among patients with eating disorders. According to Dr. Ingmar Swenne, Uppsala University Children’s Hospital, Uppsala, Sweden, taking a careful weight history from such patients is very helpful for predicting the point at which menses will return (Acta Pediatr 2004; 93:1449).

Dr. Swenne used growth charts from school health services and measurements of weight and stature to study 127 girls with eating disorders, secondary amenorrhea (lack of menses for at least 3 months), and subsequent return of menstruation. This group was compared with 43 girls with eating disorders and weight loss who did not develop amenorrhea. For all patients, weight and height were measured at the highest and lowest weights during treatment. Menarche was established from the patients’ or parents’ recall.

Patient profiles

Before their weight loss, girls who presented with amenorrhea were heavier, taller, and less lean than the population means for their age. Menarche occurred at a mean age of 12.5 years and after the onset of the eating disorder. Among these women, menses returned at approximately the weight level where amenorrhea had begun.

Among the girls who never developed amenorrhea, menarche had occurred at about the same time as in the first group (12.3 years of age). These girls were not taller, heavier, or less lean than the population mean prior to the onset of illness. At menarche, however, girls who continued to menstruate were less lean than the population average.

Higher weights may be required

Dr. Swenne reported that some patients need a weight target above 90% of “normal” weight for menses to return. According to the author, a substantial proportion of girls with eating disorders need to attain a weight or body mass index at or above the population mean before they can begin menstruating once more.