I'm almost 30 weeks along, and this numbness is driving my crazy. Swelling of hands and ankles during pregnancy can be normal since the hormones of pregnancy cause fluid retention. This is often made worse with the warm weather of summer. You should check with your doctor or midwife to evaluate whether this is the problem. It is important that you avoid diuretics in pregnancy, including herbs, except on the advice of your doctor or midwife.
Diuretics can upset the normal fluid and electrolyte balance, causing serious problems.
Be sure you are drinking plenty of fluids, eating a healthy diet and taking your prenatal vitamins. Eating watermelon may help, as it is cooling and helps with fluid retention. A simple and safe treatment that will relieve swelling is to immerse your body in water. Since it is summer, getting in a swimming pool would be great. You don't have to swim, although that's good exercise for pregnancy.