Article No. 5

Hypertension in Pregnancy

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INTRODUCTION

Preeclampsia is seen in 5% of pregnancies & 20-25% in cases of chronic hypertension. PIH was a term popularized by Dr. Jack Pritchard. Now preferably the term gestational hypertension is used.

CLASSIFICATION OF HYPERTENSION IN PREGNANCY

The ACOG Task force on Hypertension (HT) in pregnancy chose to continue using the classification scheme first introduced in 1972 by the college & modified in 2000 report of National High Blood Pressure Education Programme Working Group. There are 4 categories of Hypertension in pregnancy:

1. Preeclampsia – eclampsia
2. Chronic Hypertension
3. Chronic Hypertension with superimposed preeclampsia
4. Gestational Hypertension

1. Preeclampsia - eclampsia : Preeclampsia is a pregnancy specific multisystem disorder, seen above 20 weeks gestation. There is a new onset hypertension & new onset proteinuria. It may be superimposed on another hypertensive disorder. There may be hypertension with reduced platelets, increased liver enzymes, renal insufficiency, pulmonary edema, cerebral/visual disturbances.
   Hypertension (HT) is defined as a systolic pressure > 140 & diastolic pressure > 90. It is said to be severe if the pressure is > 160 / 110. Proteinuria is significant when qualitative dipstick is 1+ or > 300mg/24hrs. Preeclampsia must not be considered as mild. The Task Force recommends that the term mild preeclampsia be replaced by preeclampsia without severe features. Eclampsia is the convulsive phase of the disorder. There may be premonitory symptoms like headache and hyperflexia.
2. Chronic Hypertension: Chronic Hypertension is defined as high BP (> 140/90) before conception or before 20 weeks. High BP is persistent after 12 weeks postpartum.
3. Chronic Hypertension with superimposed preeclampsia: Chronic Hypertension with superimposed preeclampsia worsens the prognosis. Hypertension may be present early & proteinuria may appear after 20 weeks. Proteinuria may be present before 20 weeks but hypertension may exacerbate. There may be sudden increase in liver enzymes, reduction in platelets, headache, pulmonary edema & renal insufficiency in women with pre-existing hypertension.
4. Gestational Hypertension : Gestational hypertension is a new onset hypertension after 20 weeks gestation ≥ 140/90. There is no proteinuria.

Postpartum Hypertension: It is important to remember that preeclampsia can first develop in the postpartum period. Women need to be instructed at discharge to report to the health care provider if there is any headache, visual disturbance or epigastric pain.

There is also a phenomenon called ‘Late postpartum hypertension’ – women who are normotensive in pregnancy and develop mild HT – 2 weeks to 6 months postpartum. Little is known about this entity.

MANAGEMENT OF PREECLAMPSIA

After diagnosis the next step is evaluation of the mother & fetus.

For maternal evaluation the tests recommended by ACOG are; CBC, Platelet count, Serum Creatinine, Liver function test & Urine Protein.

For fetal evaluation the tests recommended are; USG for fetal weight, AFI, NST & Biophysical profile.

Gestational age & maternal & fetal findings are the criteria for taking decisions in management of preeclampsia.

 

 

For mild HT / preeclampsia with BP less than 160 / 110, antihypertensive drugs are not recommended. They reduce the BP but also reduce fetal growth. Bed rest & salt restriction are also not currently recommended. Also, for ‘mild preeclampsia’ Magnesium Sulphate has no role.

On the other hand severe hypertension ≥ 160/110 in pregnancy has to be treated to prevent potential cardiovascular complication (CHF, MI) renal failure & cerebrovascular accidents. Hydralazine, Labetalol & Nifedipine are equally effective & safe. Any of these can be used.

 

 

Severe hypertension can cause serious complications to the mother & fetus.

For women with severe preeclampsia at or beyond 34 weeks of gestation delivery soon after maternal stabilization is recommended.

For women with chronic hypertension who are at increased risk of adverse pregnancy outcomes (eg. History of early preeclampsia), initiating administration of daily low dose aspirin 60 – 80 mg beginning in the late first trimester is suggested.

 

 

Expectant Management allows the baby to be delivered at a more advanced gestational age. It reduces NICU requirement, Respiratory distress syndrome, Necrotising enterocolitis, intraventricular haemorrhage. However, it increases the chances of IUGR or SGA babies.

If severe preeclampsia occurs before 24 weeks, then the patient should be delivered after stabilising the maternal condition. Neonatal outcome of expectant management is poor.

Patients with preeclampsia can be delivered by LSCS/vaginally depending on the obstetric situation.

Conclusion

The most important consideration in management of women with hypertension in pregnancy is the safety of the woman & her fetus. The second is delivery of a mature newborn that will not require NICU.