Gestational hypertension resident survival guide

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Samah Obiah, MD[2], Rinky Agnes Botleroo, M.B.B.S.

Synonyms and keywords: Pregnancy-induced hypertension; PIH; Gestational hypertension

Overview

Gestational hypertension or Pregnancy-induced hypertension (PIH) , is defined as systolic blood pressure (SBP) >140 mmHg and diastolic blood pressure (DBP) >90 mmHg on at least two occasions at least 6 hours apart after the 20th week of gestation in women known to be normotensive before pregnancy and before 20 weeks’ gestation. The BP recordings used to establish the diagnosis should be no more than 7 days apart. Gestational hypertension is considered severe if there is sustained elevations in systolic BP to at least 160 mm Hg and/or in diastolic BP to at least 110 mm Hg for at least 6 hours. It is classified as mild , moderate , and severe . The WHO classified it is one of the main causes of maternal, fetal, and neonatal mortality and morbidity.gestational hypertension is one of the most common medical disorders affecting pregnancy. The most serious maternal complications of gestational hypertension include intracerebral hemorrhage, eclampsia, and renal failure, as well as hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome and posterior reversible encephalopathy syndrome (PRES).Treatment of gestational hypertension depends on blood pressure levels, gestational age, presence of symptoms and associated risk factors.

Causes

The cause of gestational hypertension is unknown. If untreated will be life-threatening, severe gestational hypertension may cause dangerous seizures (eclampsia) and even death in the mother and fetus. Because of these risks, it may be necessary for the baby to be delivered early, before the full term of pregnancy. Some conditions may increase the risk of developing the condition, including the following:

• History of hypertension
• Kidney disease
• Diabetes
• Hypertension with a previous pregnancy
• Mother's age younger than 20 or older than 40
• Multiple fetuses (twins, triplets)
• African-American race

Common Causes

Pathogenesis theories developed about the passable causes:-

• Insufficient blood flow to the uterus or abnormal placental implantation
• Damage to the blood vessels
• A problem with the immune system
• Certain genes
• Platelet activation
• Hyperlipidaemia and insulin resistance

Diagnosis

Shown below is an algorithm summarizing the diagnosis of [[disease name]] according the the [...] guidelines.

Pregnant woman previously normotensive BP ≥140/90 mmHg >20 weeks' gestation absence of symptoms that suggest preeclampsia nulligravidity black or Hispanic ethnicity obesity mother small for gestational age

Treatment

Management of gestational hypertension remains controversial, as does the classification of its severity. Delaying the interruption of pregnancy may lead to the progression of pre-eclampsia, eventually resulting in placental insufficiency and maternal organ dysfunction, with increased risk of maternal and perinatal mortality. Aims of management are minimizing further pregnancy-related complications, avoiding unnecessary prematurity, and maximizing maternal and infant survival.

Shown below is an algorithm summarizing the treatment of gestational hypertension

Woman comes with gestational hypertension

Non- pharmacological treatment

Pharmacological treatment

❑ 30 minutes of moderate exercise on most days of the week to stimulate placental angiogenesis and improve maternal endothelial dysfunction. ❑ Strict bed rest should be avoided and encouraged to maintain normal physical activity levels, as prolonged bed rest can increase the risk for venous thromboembolism, especially given the physiological hypercoagulability of pregnancy.

❑ Methyl-dopa: a centrally acting alpha-2 adrenergic agonist, used as a first line agent mainly because of its longstanding history of safety and use in pregnancy. Blood pressure control is gradual over 6-8 hours because of the indirect mechanism of action and is best for treatment of mild hypertension rather than moderate or severe hypertension. ❑ Labetalol: a nonselective beta-blocker. Should not be given in patients withasthma as it can cause bronchospasm. It is used widely in pregnancy and has proven effective in the treatment of mild to moderate hypertension, though some data shows a slight increase in small for gestational age (SGA) infants. ❑ Procardia: a calcium channel blocker, often used in pregnancy to treat mild to moderate hypertension. It has shown indication of adverse perinatal outcomes or decreased uterine blood flow. ❑ Diuretics: can be used as second line medication. It has some usefulness in pregnancy, specifically with salt-sensitive hypertension and for patients with reduced renal function. It should be carefully prescribed to avoid hypokalemia and fetal growth restriction from intravascular volume depletion. ❑ Hydralazine and clonidine have been used in certain circumstances, but are not commonly used in the longitudinal treatment of gestational or chronic hypertension. ❑ ACE inhibitors, angiotensin receptor blockers, mineralocorticoid receptor antagonists, and nitroprusside are contraindicated in pregnancy as these are teratogenic. ❑ Nitroprusside can be used as a last resort in treatment-resistant hypertension. ❑ Low dose aspirin of 81 mg or less to be initiated before 20 weeks of gestation to prevent preeclampsia as a sequelae of hypertension.

Fetal evaluation ❑ An ultrasound should be done at 16-20 weeks to provide an accurate baseline reading to evaluate the baby’s growth. ❑ Fetal movement should be counted by checking the kicks and movements. Any change in the number of kicks or how often the baby kicks may mean it is under stress. ❑ Non-stress test: this measures baby’s heart rate in response to his or her movements. ❑ Biophysical profile: this test combines a non-stress test with an ultrasound to observe the baby. ❑ Doppler flow studies: ultrasound that uses sound waves to measure the flow of the baby’s blood through a blood vessel.

Indications for preterm delivery a

The recommendations for delivery are as follows: ❑ 38-39 6/7 weeks of gestation for women not requiring medication. ❑ 37- 39 6/7 weeks of gestation for women with hypertension controlled with medication. ❑36-37 6/7 weeks of gestation for women with severe hypertension difficult to control

Intrapartum management: ❑ It is outside of the scope of the primary care provider and includes intravenous medications for acute blood pressure treatment, intravenous magnesium sulfate administration for seizure prophylaxis with suspected preeclampsia and serial serology.

Postpartum management: ❑ Postpartum hypertension until 12 weeks postpartum should be managed with medications that are safe for breastfeeding should be chosen.

Do's

• Pregnant woman should be advised to visit her health care provider regularly throughout the pregnancy.
• Patient should be encouraged to take her blood pressure medication as prescribed.
• The health care provider should prescribe the safest medication at the most appropriate dose.
• Pregnant woman should stay active and follow her health care provider's recommendations for physical activity.
• Pregnant woman should have a healthy diet and if additional help is needed, she can speak with a nutritionist.
• Pregnant woman should talk to her health care provider before taking over-the-counter medications.

Don'ts

• Strength training and pure isometric exercise, such as lifting weights and aerobic exercise should be discouraged as it can acutely elevate blood pressure to severe levels. It can also increase the risk for adverse events such as stroke.
• There is no evidence that suggest benefits in restricting sodium intake during pregnancy, thus it is not recommended to limit the intake in the prevention of preeclampsia.

References

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