Dr Jyoti Hak
Pregnancy is a physiological state associated with many alterations in metabolic, biochemical, physiological and haematological processes. If there are no complications, all these changes are reversible following a few days to few months after delivery, Maternal mortality still remains high in developing countries including India.
Hypertension is the most common medical problem encountered during pregnancy, complicating 2-3% of pregnancies. Hypertensive disorder of pregnancy represent a group of conditions with high BP during pregnancy,proteinuria and in some cases convulsion. The most serious consequences for the mother and baby are the result of preeclampsia and eclampsia.
The working group of National High Blood Pressure Education Programme (2000) classified Hypertensive disorders of pregnancy into following four types:
Gestational Hypertension
*Pre-eclampsia and Eclampsia syndrome
*Pre-eclampsia superimposed on chronic hypertension
Chronic Hypertension
Gestational Hypertension Systolic BP>140 or Diastolic BP>90 for the first time during pregnancy. With no proteinuria, BP returns to normal before 12 weeks in post partum period.
Pre eclampsia
* Minimum Criteria
* BP >140/90 after 20 wks of pregnancy
*Proleinuria>300mg/24 hrs or ? (+) on dipstick
Severe Preclampsia
*Systolic BP>160 mm of Hg
* Diastolic BP>110 mg of Hg
* With significant proteinuria>5.0g/day and evidence of endorgan damage.
* Eclampsia-Tonic, clonic convulsions not caused by coincidental neurological disorders in a patient with pre-eclampsia
* Eclampsia develop in antepartum intrapartum, and post partum period.
Chronic Hypertension
BP of > 140/90 mm before pregnancy or persisting more than six weeks after delivery.
Pathophysiology of High BP (Pre-eclampsia) in pregnancy
Pre-eclampsia is a syndrome which develops towards the end of pregnancy. Its pathogenesis is still not clearly defined hence there is no specific diagnostic tests for its predication.
The general consensus is preeclampsia. It is an endothetial cell disorder resulting in mild to severe microangiopathy of target organs such as brain, liver, kidney and placenta.
The Pathophysiology of pre-eclampsia involve maternal and fetal/placental factors. It has been considered a two stage disease, where the first stage involves abnormal placentation and the second the transition to the maternal systemic disor.
Pre eclampsia has been shown to be associated with platelet activation and excessive release of vaso constricting thromboxane pro-ceeding the onset of disease.
There may be diffuse placental thrombosis and inflammatory placental decedual vasculopathy or abnormal trophoblasic invasion of endometrium.
The wide spread endothelial dysfunction may manifest in pregnant women as dysfunction of multiple organ systems including CNS, renal, hepatic, pulmonary and heamatological system. The decrease in perfusion can manifest clinically as non-assuring fetal heart rate testing, low biophysical profile oligohydramnios and intra uterine growth restiction in seven cases.
Calcium and magnestium deficiency has been implicated as a possible cause of gestational hypertension. Dietary intake of calcium and magnesium is recommended for women during pregnancy.
Eclampsia
Eclampsia may follow pre eclampsia. It is difficult to predict which pre-eclamptic women may go on to have seizures the hallmark of eclampsia.
Prevention
Low dose aspirin (80-150mg/day) may reduce the risk of intra uterine death and perinatal death. ASA may reduce or modify the course of servere pre eclampsia. Sodium, restriction, calcium and magnesum substitution, calcium and magnesium substitution, fish oil substitution.
Anti-oxidants (Vit C and Vit E)
Medical management
Bed rest
When pre eclampsia develops at 32-34 weeks gestation often attempts are made to prolong pregnancy to allow further fetal growth and maturation.
* Monitor both fetal and maternal status.
* BP > 160/100 with proteinuria
* Decrease BP by drugs
* Like
*Labetalol (Oran or I/v)
* Alpha dopa
* Nifedipine
* Magnesium sulphate to prevent or reduce the rate of eclampsia and its complications.
* Maintaining a BP of 90mm Hg is the goal of anti hypertensive therapy.
Obstetric management
Delivery is the treatment of choice for severe pre eclampsia and eclampsia in a pregnancy over 28 weeks. For pregnancies <24 wks, the induction of labour is recommended, although the likelihood of aviable fetus is minimal
Prolonging such pregnancies results in maternal complications as well as fetal complications.
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