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Woman And Hypertension

Pregnancy Induced Hypertension / Gestational Hypertension

Introduction

Hypertension is the most common medical problem encountered during pregnancy, affecting two to three percent of pregnancies. It remains as one of common causes of direct maternal deaths in Malaysia, accounted for about 14.1 percent of total maternal deaths between 1997 until 2000. Hypertension during pregnancy carries risks for the woman and baby. It increases lifetime cardiovascular risk for the mother such as eclampsia, pulmonary edema, cerebral bleed. It can result in still birth, preterm delivery and intrauterine growth restriction for the baby.

It is defined as systolic blood pressure (SBP) ?140 mmHG and/or diastolic blood pressure (DBP) ?90mmHG

Hypertensive disorder in pregnancy basically can be divided into two : those with pre-existing chronic hypertension and those who develop new onset hypertension at or more then 20 weeks of gestation. There are various classifications available. The most recent classification of hypertension in pregnancy is endorsed by International Society for the Study of Hypertension in pregnancy (ISSHP). This classification includes the following:

  1. Pre-eclampsia – eclampsia
  2. Gestational hypertension
  3. Chronic hypertension
  4. Pre-eclampsia superimposed on chronic hypertension

Definition For Hypertensive Disorder In Pregnancy

Chronic Hypertension

Hypertension that is present before 20 weeks of gestation or if the woman is already taking anti-hypertensive drugs or if the gestational hypertension fails to resolve after delivery. It can be primary or secondary in etiology.

Secondary etiology means hypertension secondary to diseases such as chronic kidney disease, connective tissue disease e.g systemic lupus erythematosus (SLE), anti-phospholipid syndrome (APLS), endocrine disorder such as cushing’s disease, hyperaldosteronism and pheochromocytoma.

Gestational Hypertension

New hypertension occur after 20 weeks gestation without significant protein in the urine (proteinuria) followed by normalization of the BP by 3 months after delivery.

Pre-eclampsia

New hypertension presenting after 20 weeks gestation with significant proteinuria.

Eclampsia

Pre-eclampsia associated with seizure.

Severe Pre-eclampsia

Pre-eclampsia with severe hypertension and/or with symptoms, and/or blood investigation disorder.

Proteinuria

Urine dipstick protein 1+ or more should be quantified by using urine spot for urine protein creatine index (UPCI) or 24 hour urine protein. It is considered significant if more than 30mg/mmol and 300mg protein detected respectively.

NICE clinical guideline development group has defined mild, moderate and severe hypertension;

Mild Hypertension :        SBP:140-149 mmHG

DBP: 90-99 mmHG

Moderate Hypertension : SBP: 150-159 mmHG

DBP: 100-109 mmHG

Severe Hypertension :   SBP: ? 160 mmHG

DBP: ? 110 mmHG

MANAGEMENT

Antenatal (during pregnancy)

  1. The aim is to prevent, detect, monitor and manage the condition and its complication to a certain extent for the safety of the mother and the baby.
  1. Ideally it should involve multi-discipline team including primary care physician, obstetrician and physician.
  1. Women with pre-existing chronic hypertension may require prepregnancy counseling and drugs alteration to safer drugs such as metyldopa or labetolol. Angiotensin converting enzyme (ACE) inhibitor, angiotensin II receptor blocker (ARB) and chlorothiazide increase congenital abnormalities if these drugs are taken during pregnancy.
  1. Blood pressure is kept <150/90 mmHG and DBP more than 80 mmHG in women with uncomplicated chronic hypertension in order to maintain blood supply to the fetus/ baby.
  1. Chronic hypertension with target organ damage such as chronic kidney disease, BP is kept <140/90 mmHG
  1. Chronic hypertension with secondary etiology should be referred to specialist care/ combine care.
  1. Table1. Management of pregnancy with gestational hypertension
Mild Hypertension Moderate Hypertension Severe Hypertension
Admit To Hospital No No Yes. Until BP is 159/109 mmHg or lower

 

Treat No Yes. Keep SBP<150,

DBP : 80-100 mmHG

Drugs : Metyldopa/ labetolol

Second line: Nifedipine

Yes. Keep SBP <150

DBP : 80-100 mmHG

Drugs:Metyldopa/ labetolol

Second line: nifedipine

Measure Blood Pressure Not more than once a week At least twice a week At least four times a day

 

Test Proteinuria Urine dipstick or Urine protein creatinine index (UPCI) at each visit Urine dipstick or Urine protein creatinine index (UPCI) at each visit Daily using Urine dipstick or urine protein creatinine index (UPCI)

 

Blood Tests Only routine antenatal care Test kidney function, electrolytes, Blood count, liver fuction

# if no proteinuria at subsequent visit do not carry out further blood test

Test at presentation and monitor weekly
  1. Women with Pre-eclampsia should be admitted. Blood pressure should be measured four times a day or more if clinically warranted.
  1. Pre-eclampsia with moderate to severe hypertension, SBP is kept<150mmHG, DBP is kept between 80-100mmHg.
  1. Blood test should be monitored 3 times a week for pre-eclampsia with moderate to severe hypertension and 2 times a week for pre-eclampsia with mild hypertension.
  1. Women with moderate to high risk of pre-eclampsia, are advised to take aspirin 75 mg daily from 12 weeks till delivery.

High-risk : Hypertension during previous pregnancy, chronic kidney disease, autoimmune diseases such as SLE, APLS, Type 1 and 2 Diabetes, Chronic hypertension

Moderate risk : Family history of pre-eclampsia, multiple pregnancies, age ? 40 years old, last pregnancy ? 10 years and BMI ? 35kg/m2 at first visit.

Timing Of Delivery

  1. Women with uncomplicated hypertension, the pregnancy can be continued until 38 to 40 weeks, delivery can be as spontaneous or induction labour.
  1. Caesarian section is indicated when there is an obstetric reason.

Post-Natal (After Have Given Birth)

  1. Blood pressure should be measured daily for the first few days, once between 3 to 4 days or when indicated.
  1. The drug is used during pregnancy for the women with gestational hypertension can be stopped within 2 days after delivery if BP normal.
  1. Start anti-hypertensive drug if BP>149/99 mmHG for gestational hypertension or >150/100mmHg for pre-eclampsia.
  1. All patients with hypertension in pregnancy should have medical review at 6 to 8 weeks after delivery.

Contraception And Breast Feeding

  1. Oral contraceptive pill (OCP) can be used as a method of contraception. But caution should be taken in those obese or older mothers.
  1. Those whom develop hypertension while they are on OCP, the drug should be stopped.
  1. Blood pressure medications that are given during pregnancy are considered safe to take during breast feeding. There is limited information for ACE inhibitor, ARB and diuretics.

Fetal/Baby Monitoring

Chronic hypertension : Growth monitoring ultrasound is done at between 28 and 30 weeks and between 32 and 34 weeks.

Gestational hypertension: Growth monitoring ultrasound is done as per chronic hypertension if detected at less 34 weeks gestation. No need to repeat unless clinically indicated.,

  1. Doppler ultrasound to monitor placenta blood flow on the affected baby.
  1. Count fetal movement every day, at least 10 kicks a day. Seek obstetrician if fetal less active.

CASES:

A 40 year old lady, presented at 11 weeks gestation. Her BP was 150/99 mmHg. She was on ACE inhibitor.

Diagnosis: Chronic hypertension

Management: Stop ACE inhibitor. Switch to metyldopa/ labetolol. Add tablet Aspirin 75 mg daily

27 year old lady, first pregnancy, presented at 10 weeks pregnancy. Her BP was 140/90mmHg. She had persistent low potassium. No palpitation and excessive sweating.

Diagnosis: Chronic hypertension. Need to investigate for secondary etiology.

Management: No need to treat as mild hypertension, Potassium correction. Combine care. Monitor BP and urine dipstick each antenatal visit.

Third pregnancy, noted her BP at 28 weeks gestation was 150/100mmHG. Urine dipstick: 1+, UPCI was 20mg/mmol.

Diagnosis: Gestational hypertension

Management: Metyldopa/ labetolol. Monitor BP twice a week. Urine dipstick at each visit.

35 year old clerk, presented at 35 weeks of gestation. BP was 150/90mmHg. UPCI was 40mg/mmol.

Diagnosis: Preeclampsia

Management: Admit ward. BP monitoring 4 times a day. Keep BP <150/100 mmHg. Treat if BP is higher. Blood test at least twice a week.

References

  1. National Institute For Health And Clinical Excellence. (August 2010). Nice Clinical Guideline 107, national calloborating centre for womens’ and childrens’ health. Hypertension in pregnancy. The management of hypertensive disorder during pregnancy Retrieved from www.nice.org.uk/nicemedia/live/13098/50418/50418.pdf
  1. Ministry Of Health (February 2008). Clinical Practice Guidelines. Management of Hypertension. (3rd ed.) page 31-35 Retrieved from: www.moh.gov.my/attachments/3885
  2. Ellen W.Seely MD, Cynthia Maxwell MD. American Heart Association. Chronic Hypertension In Pregnancy. Retrieved from n.circ.ahajournals.org/content/115/7/e188.full.pdf+html
  1. Michael P Carson, MD (Feb 2012).Hypertension and pregnancy. Retrieved from http://emedicine.medscape.com/article/261435-overview#
Last Reviewed : 9 November 2015
Writer : Dr. Norliza Binti Zainudin
Translator : Dr. Norliza Binti Zainudin
Accreditor : Dr. Muhaini Othman

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