A brief article about potassium-sparing diuretics can be found at this page by the Mayo Clinic's Health Oasis.

http://www.mayohealth.org/mayo/askphys/qacurr_5.htm

The American Heart Association present High Blood Pressure, a page including AHA's recommendations, the effects of salt and sodium on hypertension, how overweight leads to hypertension, and much more.

http://www.amhrt.org/Heart_and_Stroke_A_Z_Guide/hbp.html

High blood pressure in pregnancy, also known as pre-eclampsia, occurs in almost 10% of pregnancies and can be lethal to the mother, fetus or newborn, or both.

http://www.musc.edu/nursing/midwife/pregncy/preclamp.htm