hi and thanks for the query, it would be interesting if she has abnormally just started drinking a lot of water or not. If that s the case, during a fasting blood sugar to exclude diabetes mellitus shall be very important. It is not unusual to experience limb swelling in pregnancy. However. a careful evaluation should be done to exclude the association of the swelling to pregnancy induced hypertension or eclampsia. Urine proteins are very important and measurements of the blood pressure compared to the basal blood pressure to exclude pre eclampsia. While waiting to meet the obstetrician to exclude all of these possibilities, its worth while that she avoid long standing positions, and assume positions when lying done with the limbs higher above the rest of the body to facilitate drainange . Thanks and hope this helps, Luchuo, MD.