Hello Estrogen is a hormone found in abundant amount in the female ( child bearing age ) . When female approach toward menopause ( perimenopause ) age, gradually quantity of estrogen decrease hence female feel such type of symptoms as hot flashes , sleeplessness and anxiety , sweating , mood swings . For the compensation for this estrogen is advised , so in other way ,we can say that this is a natural hormone ,so you can take . Help in perimenopause symptoms . In rare cases this causes weight gain due to edema. So need not to worry , take this hormone as advised your doctor and you will feel better. For weight gain take regular healthy diet and exercise continue. Good luck.