6.7 Hypertensive Disorders in Pregnancy

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Hypertension in pregnancy is a condition affecting 5%–10% of pregnancies worldwide28. Recent survey by NIPORT 2022, MOHFW has revealed that prevalence of pregnancy induced hypertension (PIH) in Bangladesh is 10.1% (95% CI, 9.0, 11.2) among pregnant women with gestational age >20 weeks29. Preeclampsia and eclampsia are one of the common obstetric emergencies. About 4.6% of pregnancy are complicated with preeclampsia.20 Eclampsia is the cause of 24% maternal death in Bangladesh29.Most of the preeclampsia and eclampsia are preventable. Maternal risks include placental abruption, stroke, multiple organ failure (liver, kidney), disseminated vascular coagulation. Fetal risks include intra uterine growth retardation, preterm birth, intrauterine death.

Hypertensive disorders in pregnancy can be classified into the following groups:

1. Pregnancy induced hypertension or gestational hypertension: Defined as systolic blood pressure ≥140 mmHg and/or diastolic blood pressure (DBP) ≥90 mmHg in a previously normotensive pregnant woman after ≥20 weeks of gestation in the absence of proteinuria or new signs of end-organ dysfunction. The blood pressure readings should be documented on at least two occasions 4 hours apart.

2. Pre-eclampsia: Occurrence of new-onset hypertension plus new–onset proteinuria after 20 weeks of gestation with high blood pressure:

  • SBP ≥140 or DBP ≥90 mmHg on two occasions at least 4 hours apart after 20 weeks of gestation, at the time or after delivery in a woman with a previously normal blood pressure.

And significant proteinuria:

  • ≥ 300 mg / 24-hour urine collection or
  • Protein/creatinine ratio ≥0.3 (each measured as mg/dl)
  • Dipstick reading of 1+ (used only if other quantitative methods not available)
  1. Mild pre-eclampsia: SBP ≥140 to <160mmHg & DBP ≥90 to <110mmHg after 20 weeks gestation without significant proteinuria with no evidence of organ dysfunction
  2. Severe pre-eclampsia: SBP ≥ 160 mmHg and / or DBP ≥ 110 mmHg after 20 weeks gestation with significant proteinuria or new-onset hypertension with the new onset of any of the following:
  • Thrombocytopenia- platelet count <100000/microliter
  • Renal insufficiency- serum creatinine>1.1 mg dl or a doubling of serum creatinine concentration
  • Impaired liver functions- elevated liver transaminases ≥ twice normal concentration
  • Pulmonary edema
  • Cerebral or visual symptoms
    • Headache (increasing frequency, not relieved by regular analgesics).
    • Blurred vision.
  • Oliguria (passing less than 400 mL urine in 24 hours).
  • Upper abdominal pain (epigastric pain or pain in right upper quadrant)

3. Eclampsia: New onset hypertension after 20 weeks gestation with significant proteinuria or ≥1+ on dipstick and sometimes with altered sensorium or loss of consciousness with other symptoms and signs of severe preeclampsia along with convulsions.

4. Chronic Hypertension: Elevated blood pressure (≥ 140/90 mmHg) diagnosed before pregnancy or developed during pregnancy before 20 weeks and persists after delivery is known as chronic hypertension.

5. Chronic hypertension with superimposed preeclampsia: Women with hypertension only in early gestation who develop proteinuria after 20 weeks gestation. Women with hypertension with proteinuria before 20 weeks of gestation who-

a) Experience a sudden exacerbation of hypertension or need to escalate dose of antihypertensive drug in previously well controlled BP
b) Sudden increase in liver enzymes to abnormal levels
c) Presence with decrement in platelet levels to below 100,000/ microliter
d) Manifest symptoms such as right upper quadrant pain and severe headache
e) Develop pulmonary edema
f) Develop renal insufficiency
g) Have sudden, substantial and sustained increases in protein excretion

Diagnosis of Preeclampsia and Eclampsia

Diagnosis of Preeclampsia and Eclampsia30,31

Preeclampsia and Eclampsia is diagnosed mainly by symptoms and signs.

Symptoms:

  • Generalized or localized headache,
  • nausea, vomiting and epigastric pain,
  • restlessness, dizziness, blurred vision,
  • swelling of feet, hands and or face,
  • history of convulsions

Signs:

  • oedema of feet, hands and or face plus other signs of pre-eclampsia,
  • high blood pressure,
  • proteinuria,
  • eclamptic fit,
  • hypertensive retinal changes

Investigations

  • Complete blood count- platelet count <100000/microliter (Thrombocytopenia)
  • Random Blood sugar
  • Serum creatinine- serum creatinine >1.1 mg/dl or a doubling of serum creatinine concentration (Renal insufficiency)
  • Serum electrolytes
  • Liver Function Test- elevated liver transaminases ≥ twice normal concentration (impaired liver functions)
  • Coagulation profile
  • Bed side clotting test
  • Urine parameters
    • Test for 24 hours urinary protein- Greater than or equal to 300 mg per 24- hour urine collection
    • Urine for albumin and sugar
    • Protein creatinine ratio- 0.3 or ≥1+ on Dipstick (each measured as mg/dl
    • Dipstick reading of 1+ (used only if other quantitative methods not available)

Prevention of Hypertension in Pregnancy

Primary prevention

1. Right timing of pregnancy

  • Delaying the first pregnancy so that a woman can begin her gestation at the age of 20 or more
  • Women aged 35 years or more should not go for a baby if not absolutely necessary
  • Birth spacing of 2-5 years

2. Controlling weight

  • Those women whose pregnancy has begun with overweight should take balanced food regularly (an increase of 5-7 kgs of weight during pregnancy)

3. Calcium tablets during pregnancy

  • After 12th week of pregnancy, women should take one-gram (1000mg – 2 tablets of 500 mg) calcium tablet every day until delivery

4. Low dose aspirin during pregnancy

  • Intake of 150 mg of aspirin orally starting from 12fth week – 19th week of gestation by women at high risk for developing PE and continue until delivery.

Secondary prevention:

Secondary prevention includes measuring high blood pressure as well as albumin in urine at primary stage at all opportunity in 8 ANC, including self-measurement.

Management:

A) General Management

  • Close supervision, restriction of activities, Diet: high protein diet

B) Specific Management:

Gestational hypertension:

Start drug treatment if gestational hypertension with blood pressure levels >140/90mmHg, Hospitalization if blood pressure levels SBP ≥170 or DBP ≥110mmHg.

Anti-hypertensive drugs: -

  • Labetalol (The initial dose is 100mg twice daily, may be increased up to 200- 400mg twice daily, a maximum dose of 2.4 gm)
  • Methyl dopa (250 mg tds, max 8 g/ day)
  • Nifedipine 10-20 mg bid (extended release)

Severe Pre-eclampsia:

  • Anti-hypertensive drugs (IV)
  • Anti-convulsant (MgSO4 therapy for prevention of convulsion)

Anti-hypertensive drugs:

  • Labetalol regime
    • Injection labetalol 1 amp (50mg/10ml)
      • 4 ml (20mg) slow IV then 8-10ml (40-80 mg) every 15 min until DBP is 90 mmHg. Maximum dose 300 mg (60ml)
      • (Include maintaining dose)
  • Hydralazine regime
    • IV bolus regime
      • Injection hydralazine 1 amp (20mg) + 10 ml distilled water
      • ml (5mg) slow IV over 3 to 4 min
      • Repeat 1 ml (2mg) every 15 min until DBP is 90 mmHg
    • IV infusion regime
      • Injection hydralazine 1 amp (20mg) dissolved in NS (200ml) in IV infusion at 8-10 drops/min
      • BP checked at every 15 mins interval until DBP is 90 mmHg

Pre-eclampsia with pulmonary edema:

  • Diuretics: used only in cardiac failure and pulmonary edema (IV Frusemide).
  • Nitroglycerin: short term therapy may be given only when other drugs have failed.

Referral criteria

Consider referral for tertiary level care of women who have:

  • Oliguria that persists for 48 hours after delivery
  • Coagulation failure (e.g., coagulopathy)
  • Hemolysis, elevated liver enzymes and low platelets (HELLP syndrome)
  • Persistent coma lasting more than 24 hours after convulsion.
  • Women at risk of preeclampsia are defined based on the presence of one or more high risk factors such as history of preeclampsia, multifetal gestation, renal disease, autoimmune disease, type 1 or type 2 diabetes, chronic hypertension or presence of more than one of several moderate risk factors such as first pregnancy, maternal age of 35 years or older, body mass index greater than 30, family history of preeclampsia, sociodemographic characteristics, and personal history factors (LBW or previous adverse pregnancy outcome).