Weight variation in a cohort of women using copper IUD for contraception.

The objective of this study was to assess weight changes over time in reproductive-age women using nonhormonal contraception [copper intrauterine device (IUD) users]. Baseline variables recorded included age, parity, decade when the IUD was inserted and the presence of hypertension. A total of 1697 IUD users were followed for 7 years of use. The mean age (+/- SD) of the women at the beginning of follow-up was 27.6 +/- 5.8 years and the mean height (+/- SD) was 150 +/- 10 cm. The mean weight (+/- SD) at the time of IUD insertion was 58.5 +/- 0.30 kg. After 5 and 7 years of follow-up, the mean weight (+/- SD) was 61.2 +/- 0.33 kg and 62.4 +/- 0.51 kg, respectively. At insertion, the body mass index mean (+/- SD) was 24.5 +/- 0.12 and after 3 years it was 25 +/- 0.14, remaining above 25 up to the 7th year of observation. During the 7 years of follow-up, older women gained more weight than younger women. Parity, decade of IUD insertion and hypertension were not noted to be significant determinants of weight variation. In conclusion, this cohort of lower and middle class Brazilian copper IUD users tended to gain weight during their reproductive life, independent of other factors. These observations may improve counseling of women regarding the prevention of age-related obesity.