Pregnancy Hypertension

Effective treatment of pregnancy-induced hypertension improves fetal and perinatal survival. There is a lack of good clinical trial evidence on which to base recommendations of one agent over another. Instead, drug usage reflects longevity of use without obvious harm to the fetus. Hence methyldopa is still the drug of choice for many obstetricians.35 Calcium-channel blockers (especially nifedipine) are common second-line drugs; parenteral hydralazine is reserved for emergency reduction of blood pressure in late pregnancy, preferably in combination with a (3-blocker to avoid unpleasant tachycardia. (3-blockers (labetalol and atenolol) are often

35 Methyldopa: follow-up studies show no intellectual impairment in children up to age 7.5 years (for atenolol, see: Butters L 1990 British Medical Journal 301: 587).

effective and are probably the drugs of choice in the third trimester; there is anecdotal evidence to suggest growth retardation with p-blockade used in first and second trimester. Diuretics reduce the chance of developing pre-eclampsia, but are avoided in pre-eclampsia itself because these patients already have a contracted circulatory volume. ACE-inhibitors (and by implication angiotensin ATt receptor antagonists) are absolutely contraindicated during pregnancy, where they cause fetal death, typically mid-trimester. There is no definite evidence that ACE inhibitors — or any of the commonly used antihypertensive drugs — are teratogenic, and women who become pregnant while receiving these should be reassured but should, of course, then discontinue the ACE inhibitor or ATj receptor antagonist.

Raised blood pressure and proteinuria (preeclampsia) complicates 2-8% of pregnancies and may proceed to fitting (eclampsia), a major cause of mortality in mother and child. Magnesium sulphate halves the risk of progress to eclampsia (typically 4 g i.v. over 5-10 min followed by 1 g/hour by i.v. infusion for 24 hours after the last seizure).36 Additionally, if a woman has one fit (treat with diazepam), then the magnesium regimen is superior to diazepam or phenytoin in preventing further fits.37

Aspirin, in low dose, was reported in early studies to reduce the incidence of pre-eclampsia in at-risk patients, but a more recent meta-analysis has not supported this. Consequently, it is not routinely recommended.

Blood Pressure Health

Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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