High blood pressure (BP) before pregnancy is called chronic hypertension (CHTN), and is associated with an increased risk of development of pregnancy related high BP called preeclampsia, preterm delivery, decreased growth of the fetus, fetal death, premature separation of the placenta from the uterus resulting in damage to the fetus and cesarean delivery. Longer duration and severity of CHTN in pregnancy leads to worse outcomes for the mother and the fetus. Treatment of mild CHTN in pregnancy does not improve these outcomes, and therefore, medications to lower BP are used for moderate to severe hypertension. To date the literature on the medications used in pregnancy is extremely limited.

Methyldopa is used as a first choice medicine for CHTN in pregnancy. It acts on the central nervous system (CNS) by relaxation of the blood vessels leading to a decrease in BP. It does not decrease the blood flow to the uterus, placenta, or the fetus (4). Methyldopa is a weak antihypertensive medicine given three or four times a day and frequently needs changes in the dose or may require an additional medication to control BP. This may lead to a greater chance of non compliance. Another option is Clonidine which is an effective antihypertensive treatment and is available in many forms (oral, parenteral, and transdermal.) It acts on the maternal CNS. Clonidine is not associated with teratogenic or neonatal side effects. Transdermal clonidine (catapres-TTS®) is a preparation of clonidine hydrochloride that can be released and absorbed transdermally over a 7-day period.

The study will determine differences in compliance between the two antihypertensive regimens- oral methyldopa and Catapres-TTS, comparisons of patient tolerability, compliance and adequacy of BP control, as well as provide information on an alternate option for BP control.