Hypertensive diseases in pregnancy

Chapter 14 Hypertensive diseases in pregnancy



CHAPTER CONTENTS


Classification 117
Gestational hypertension 117

Pre-eclampsia 117

Chronic hypertension 118

Pre-eclampsia superimposed on chronic hypertension 118

Gestational hypertension 118

Pre-eclampsia 119
Pathogenesis 119

Prevention 119

Management 119

Eclampsia 120
Pathophysiology 120

Clinical picture 120

Management of eclampsia 120

Medical and drug treatment 121

Prognosis in pre-eclampsia and eclampsia 121

Chronic hypertension 121
Pathophysiology 121

Treatment 122

Renal disease in pregnancy 122

Between 5 and 8% of pregnancies are complicated by hypertensive diseases. These are gestational hypertension, pre-eclampsia, chronic hypertension, essential and secondary and superimposed pre-eclampsia.



CLASSIFICATION



Gestational hypertension


Gestational hypertension is classified as hypertension that arises after 20 weeks’ gestation without any of the other features of pre-eclampsia and resolves within 3 months of delivery.



Pre-eclampsia


Pre-eclampsia is a multisystem disorder; hypertension is usually the first manifestation, followed by proteinuria. The clinical diagnosis of pre-eclampsia requires the onset after 20 weeks’ gestation of hypertension and one or more of:


• Proteinuria – >300 mg/24 h or urine protein/creatinine ratio >30 mg/mmol

• Renal insufficiency – serum/plasma creatinine >0.09 mmol/L or oliguria

• Liver disease – raised serum transaminases and/or severe epigastric/right upper quadrant pain

• Neurological problems – convulsions (eclampsia); hyperreflexia with clonus; severe headaches with hyperreflexia; persistent visual disturbances (scotomata)

• Haematological disturbances – thrombocytopenia; disseminated intravascular coagulation; haemolysis

• Fetal growth restriction.

The hypertension of pre-eclampsia returns to normal within 3 months of delivery.



Chronic hypertension



• Essential hypertension: blood pressure ≥140 mmHg systolic and/or ≥90 mmHg diastolic (K5) prior to conception or in the first half of pregnancy without an apparent underlying cause.

• Secondary hypertension: hypertension associated with renal, renovascular and endocrine disorders and aortic coarctation.


Pre-eclampsia superimposed on chronic hypertension


This is diagnosed when one or more of the systemic features of pre-eclampsia develops after 20 weeks, i.e. in addition to a rise in blood pressure and/or a sudden increase in protein excretion.



GESTATIONAL HYPERTENSION


Pregnancies complicated by gestational hypertension have a good prognosis. The blood pressure should be carefully monitored and this can normally be done in a Day Assessment Unit or with ambulatory home blood pressure monitoring. Careful surveillance should be maintained to exclude the development of pre-eclampsia.


If the blood pressure exceeds 140/90 then antihypertensive therapy, as detailed in Table 14.1, is commenced, with the objective of maintaining the systolic pressure between 110 and 140 mmHg and the diastolic between 80 and 90 mmHg.


Table 14.1 Summary of the management of pregnancy-induced hypertension























Classification Observations Treatment
Gestational hypertension Report rise in blood pressure or excessive weight gain to obstetrician Assess in day assessment unit or ambulatory blood pressure monitoring at home
Moderate pre-eclampsia
In hospital:

Four-hourly recording of the blood pressure

Twice-daily urine testing for protein

Regular observation of the patient’s condition, including fluid intake and output

Bed rest, but toilet privileges allowed
Admit to hospital

Sedation (if indicated)

Methyldopa (starting) 250 mg two to three time daily increasing to max. 3 g daily

Labetalol (starting) 100 mg twice daily or atenolol (starting) 100 mg in evening or oxprenolol (starting) 20 mg three times daily or methyldopa (starting) 250 mg three times daily

Nifedipine 10–20 mg twice daily to max. 40 mg b.d.
Severe pre-eclampsia
Two-hourly blood pressure recording for 6 hours, then 4-hourly

Urine testing for protein twice daily

Fluid intake and output recorded

Careful observation of the patient for the signs of imminent eclampsia

Complete bed rest for 24 hours, thereafter possible toilet privileges
Admit to hospital

Depending on the severity of the illness give:
a. Magnesium sulphate (see p. 121).

b. Hydralazine – start 5–10 mg IV slowly, repeat 20–30 min. Continue infusion 50–300 μg/min, rate to keep BP around 140/90
Imminent eclampsia
The patient requires careful systematic observation as eclampsia is a possible outcome

The blood pressure requires frequent estimation, at intervals determined by the obstetrician

Fluid intake and urinary output must be measured meticulously, and the urine tested quantitatively for protein
Magnesium sulphate (see p. 121).

Hydralazine intravenously

Caesarean section


PRE-ECLAMPSIA



Pathogenesis

Related posts:

  1. Variations in the duration of pregnancy
  2. Miscarriage and abortion
  3. The epidemiology of obstetrics
  4. Ovulation and the menstrual cycle

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Jun 15, 2016 | Posted by in OBSTETRICS | Comments Off on Hypertensive diseases in pregnancy

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