Hypertension in Pregnancy
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A sustained BP reading above 140/90 mm Hg during pregnancy has implications both for the mother and the foetus: reduction of BP clearly reduces risks. Two types of situations are possible:
HYPERTENSION IN PREGNANCY
A sustained BP reading above 140/90
mm Hg during pregnancy has implications both for the mother and the foetus:
reduction of BP clearly reduces risks. Two types of situations are possible:
·
A woman with preexisting essential hypertension
becomes pregnant.
·
Pregnancy induced hypertension; as in toxaemia
of pregnancy—preeclampsia.
Toxaemic hypertension
is associated with a hyperadrenergic state, decrease in plasma volume (despite
edema) and increase in vascular resistance.
In the first category
the same therapy instituted before pregnancy may be continued. However, one of
the ‘safer’ drugs listed below may be substituted if one of the ‘drugs to be
avoided’ was being used.
Antihypertensives
To Be Avoided During Pregnancy
Diuretics: Tend to reduce blood
volume— accentuate uteroplacental
perfusion deficit (of toxaemia)—increase risk of foetal wastage, placental
infarcts, miscarriage, stillbirth.
ACE inhibitors, AT1 antagonists: Risk of foetal damage, growth retardation.
Nonselective β blockers: Propranolol has been implicated to cause low birth weight,
decreased placental size, neonatal bradycardia and hypoglycaemia.
Sod. nitroprusside: Contraindicated in
eclampsia.
Antihypertensives Found Safer During Pregnancy
Hydralazine
Methyldopa (a positive
Coombs’ test occurs, but has no adverse implication).
Dihydropyridine CCBs:
discontinue before labour as they weaken uterine contractions.
Cardioselective β blockers and those
with ISA, e.g. atenolol, metoprolol, pindolol, acebutolol: may be used if no
other choice.
Prazosin and
clonidine—provided that postural hypotension can be avoided.
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