Variations in body-weight of young women during the menstrual cycle

Abstract

Daily weights were followed for 68 days in 28 young women (aged 18-20 years) living and eating in the same residential hall and attending similar courses at the university. Two subjects completed 3 menstrual cycles, 16 completed 2 cycles, and 10 only 1 cycle, making a total of 48 cycles. Some subjects tended to lose or gain weight, and the appropriate corrections were made in the records of their body-weight. For comparison the cycles were divided into 8 parts, using the beginning and end of menstruation, and the time of ovulation as dividing lines: 1st and 2nd half of menstruation, the 1st and 2nd half of postmenstrual phase (including the day of ovulation), and the 4 quarters of the postovulatory phase. A distinct pattern of the average change in body-weight was obtained by 2 separate methods of analysis. The body-weight increased steadily during the latter half of the postovulatory phase (the premenstrual phase), reaching its highest value during the 1st half of menstruation. Thereafter the weight fell rapidly to low values during the postmenstrual phase. Ovulation appeared to be associated with a minor peak in weight just after ovulation had taken place. The findings from the analysis of the completed cycles were similar to those obtained previously from the analysis of the day-to-day fluctuations in body-weight. Comparison of 2 or more cycles from the same subject demonstrated that no 2 cycles were similar in all respects, although they might agree in some of them, such as length of cycle, length of time from ovulation until the next menstrual flow, coefficient of variation in body-weight, incidence of day-to-day variation greater than 0.5 kg, and profile of graphs of body-weight.