MANAGEMENT HTN IN PREGNANCY

DEFINITIONS

The definition of gestational hypertension is somewhat controversial. Some clinicians therefore recommend close observation of women with an incremental rise in blood pressure by 30 mm Hg systolic or 15 mm Hg diastolic even if absolute blood pressure does not exceed 140/90 mm Hg.

Gestational hypertension is the most frequent cause of hypertension during pregnancy. The incidence ranges between 6% and 29% in nulliparous women and between 2% and 4% in multiparous women. Maternal and perinatal morbidities are substantially increased in women with severe gestational hypertension. Indeed, these women have increased risk for morbidity compared with women with mild preeclampsia. The rates of abruptio placentae, preterm delivery (at less than 37 and 35 weeks), and small-for-gestational-age (SGA) infants in these women are similar to those seen in women with severe preeclampsia.

INCIDENCE OF CHRONIC HYPERTENSION The frequency of chronic hypertension in pregnancy is estimated at 1% to 5%. The etiology and severity of chronic hypertension are important considerations in the management of pregnancy Chronic hypertension is subdivided into primary (essential) and secondary. Chronic hypertension during pregnancy can be subclassified as either mild or severe, depending on the systolic and diastolic BP readings. Systolic and diastolic (Korotkoff phase V) BPs of at least 160 mm Hg or 110 mm Hg, respectively, constitute severe hypertension.

Pregnancies complicated by chronic hypertension are at increased risk for the development of superimposed preeclampsia and abruptio placentae. The reported rates of preeclampsia in the literature in mild hypertension range from 14% to 28%. The rate of preeclampsia in women with severe chronic hypertension ranges from 50% to 79%. The overall rate of superimposed preeclampsia was 25%. The rate was not affected by maternal age, race, or presence of proteinuria early in pregnancy. However, the rate was significantly greater in women who had hypertension for at least 4 years (31% versus 22%), in those who had preeclampsia during a previous pregnancy (32% versus 23%), and in those whose diastolic BP was 100 mm Hg or higher (42% versus 24%). 1

Antepartum Management of Mild GESTATIONAL HYPERTENSION These patients require close observation of maternal and fetal conditions. Maternal evaluations require weekly prenatal visits, education about reporting preeclamptic symptoms, and evaluation of complete blood count, platelet count, and liver enzymes.

Fetal evaluation includes ultrasound examination of fluid and estimated fetal weight at the time of diagnosis and weekly non stress testing. Restriction dietary salt as well as physical activity has not proved beneficial Control of maternal BP with antihypertensive drugs does not improve pregnancy outcome In the absence of progression to severe hypertension or preeclampsia, women with gestational hypertension can continue pregnancy until 37 weeks’ gestation

In women with gestational hypertension full assessment should be carried out in a secondary care setting by a healthcare professional who is trained in the management of hypertensive disorders. nulliparity age 40 years or older pregnancy interval of more than 10 years family history of pre-eclampsia multiple pregnancy BMI of 35 kg/m² or more gestational age at presentation previous history of pre-eclampsia or gestational hypertension pre-existing vascular disease pre-existing kidney disease.

In women with gestational hypertension who have given birth, measure blood pressure: daily for the first 2 days after birth at least once between day 3 and day 5 after birth as clinically indicated if antihypertensive treatment is changed after birth. In women with gestational hypertension who have given birth: continue use of antenatal antihypertensive treatment consider reducing antihypertensive treatment if their blood pressure falls below 140/90 mmHg reduce antihypertensive treatment if their blood pressure falls below 130/80 mmHg. If a woman has taken methyldopa † to treat gestational hypertension, stop within 2 days of birth. For women with gestational hypertension who did not take antihypertensive treatment and have given birth, start antihypertensive treatment if their blood pressure is higher than 149/99 mmHg.

Offer women who have had gestational hypertension and remain on antihypertensive treatment 2 weeks after transfer to community care, a medical review. Offer women who have had gestational hypertension a medical review at the postnatal review (6–8 weeks after the birth). Offer women who have had gestational hypertension and who still need antihypertensive treatment at the postnatal review (6–8 weeks after the birth) a specialist assessment of their hypertension. _______________ ____________________________________________

Recommended Management of chronic Hypertension Based on the avail- able data, there is no compelling evidence that short- term antihypertensive therapy is benefcial for the mother or the fetus in the setting of low-risk hypertension except for a reduction in the rate of exacerbation of hypertension.

Therapy suggested:  Secondary HTN  End organ damage  Dyslipidemia  Maternal age over 40  Microvascular disease  History stroke  Previous prenatal loss

Women with long-standing hypertension for several years, particularly those with a history of poor compliance or poor BP control, should be evaluated for target organ damage, including : left ventricular hypertrophy, Retinopathy, and renal injury an ECG examination and echocardiography if the ECG is abnormal, ophthalmologic evaluation, and creatinine clearance.

Methyldopa remains the drug most commonly recommended to treat hypertension during pregnancy For women with diabetes mellitus and vascular disease, oral nifedipine is recommended.

Systolic BP ≥ Diastolic BP ≥ Labetalol: 20 mg IV Constant Infusion: 1-2 mg/min Instead of intermitent therapy Hydralazine: 5 mg IV 5 mg up to min no response OR min no response

Calcium Cahnnel Blockers: SR nifidipine mg Q 30 min Nitroprusside: mcg/kg/min

Drugs Contraindicated in Pregnancy Nitroprusside mcg/kg/min can be considered an agent of last resort for urgent control of refractory severe HTN. Angiotensin Converting Enzime (ACE) Inhibitors

Do not offer birth to women with chronic hypertension whose blood pressure is lower than 160/110 mmHg, with or without antihypertensive treatment, before 37 weeks. Offer birth to women with refractory severe chronic hypertension, after a course of corticosteroids (if required) has been completed.