nea, respiratory problems (like asthma), osteoarthritis, infertility and other reproductive complications, complications during pregnancy and birth defects, and mental health conditions. [42] [36] Women who gain 20 pounds or more between age 20 and midlife double their risk of postmenopausal breast cancer. [36] For every 2 pound weight increase, the risk of developing arthritis rises 9-13%. [36]