Standard Treatment Guidelines For Hypertension In Pregnancy, Preeclampsia

Hypertension is the most common medical problem encountered during pregnancy, complicating 2-3% of pregnancies.

The Ministry of Health and Family Welfare has issued the Obstetrics and Gynecology Guidelines for Hypertension In Pregnancy, Preeclampsia. Following are the major recommendations:

Case Definition:

when high blood pressure is noted during pregnancy, it may be one of the following:

1. Gestational Hypertension: new onset BP elevation of systolic >140 mm Hg/ diastolic >90 mm Hg on 2 occasions 6 hrs apart after 20 wks gestation in a previously normotensive woman


2. Preeclampsia - gestational hypertension and persistent proteinuria ≥ 1+ on dipstick urine analysis or >300mg/24 hours occurring >20 weeks pregnancy in a previously normotensive, non proteinuric woman. Oedema is not a defining sign of PE.


3. Eclampsia - Generalized convulsions occurring after the 20th week of pregnancy in a patient with underlying pre-ecclampsia

Incidence: 2-8%

A higher incidence is seen in women with age > 40, nulliparity, family or prior pregnancy h/o PIH, past h/o diabetes mellitus, chronic hypertension, renal disease, antiphospholipid syndrome, and present pregnancy with multifetal gestation and vesicular mole.

Complications

If not recognized and managed appropriately, preeclampsia can result in complications such as eclampsia, hypertensive encephalopathy, pulmonary edema, liver haematoma/rupture, renal failure, ARDS, HELLP syndrome, disseminated intravascular coagulation, cortical blindness.

Prediction

In situation 1

Roll over test at 28 -30 wks: increased blood pressure of 20 mm Hg when patient rolls over from lateral to supine position means a positive test. The test has a high negative predictive value although the positive predictive value is low.

In situation 2

If the facility for colour doppler is available it can be performed at 24-26 weeks: Persistence of diastolic notching in uterine artery after second trimester can be predictive of preeclampsia.

Prevention

Low dose Aspirin (50-100mg/d) may reduce the risk of PE by 15%. It can be started in high risk at 20 weeks and has to be stopped at 34 weeks gestation.

Optimal Diagnostic Criteria, Investigations, Treatment & Referral Criteria

Optimal Standards in Situations where technology and resources are limited

PHC

The patient should be transferred to higher centre as soon as a diagnosis of preeclampsia is made. However, if the patient presents with eclampsia/impending eclampsia, she should be started on MgSO4 and anti hypertensive (described later) and transferred after stabilizing.

Non-Metro situations

Patient should be hospitalized and evaluated in detail to assess the severity of disease, gestational age, maternal and fetal well being:

History:

Present illness - symptoms of impending eclampsia

Past- diabetes mellitus, chronic hypertension, renal disease, anti-phospholipid syndrome

Family - hypertension, diabetes mellitus

Obstetric - h/o PE in previous pregnancy, preterm birth, IUGR, stillbirth or neonatal death

Examination:

Complete general physical and systemic examination should be carried out including record of maternal weight, BMI, pulse, B.P in all four limbs, and testing of limb reflexes (presence of hyper-reflexia indicates impending eclampsia).

Obstetric Examination:

Assess for presentation, fetal heart rate, estimated fetal weight, IUGR and accidental hemorrhage in severe cases. Per-vaginal examination may be done if patient is complaining of pain abdomen, or if termination of pregnancy is decided.

Investigations:

 CBC, hematocrit, platelets, P/S for haemolysis

 Serum uric Acid, creatinine, blood urea

 S. Bilirubin, SGOT, SGPT, LDH

 Urine R/E, M/E, C&S*

 Total urinary protein excretion on 24-hr specimen*

 Fundoscopy

Diagnosis of severe preeclampsia is made if any of the following is present:

 SBP > 160 or DBP 110 mm Hg on 2 occasions six hours apart

 Proteinuria > 2+ or > 5 gms/ 24 hours

 Oliguria (urine output< 400 ml/24 hours)

 Sign and Symptoms of impending eclampsia (Nausea, vomiting, persistent headache, epigastric pain, visual disturbances)  Placental abruption, IUGR

 Platelets< 100,000 /cubic mm

 Micro angiopathic hemolysis (increased LDH)

 Elevated liver enzymes (SGOT > 70 IU/ L)

 Serum Creatinine> 1.2 mg % unless previously elevated

Referral Criteria - All cases of severe PE and threatened eclampsia should be referred to situation 2 following the initial management and stabilization, as the clinical course of these patients is unpredictable and may necessitate maternal and fetal intensive care and monitoring.

At Super Speciality Hospital

Mild – Hospitalization is advised although complete bed rest is not advisable.

Severe- Immediate hospitalization is recommended if BP ≥ 160/100 or alarm signs.

Maternal Assessment:

• Blood pressure measurement: At least 4 times a day, more often in severe cases

• Urine quantification (24 hour protein ) on admission, repeat not required

• Blood tests: Monitor kidney function, electrolytes, full blood count, transaminases, bilirubin twice a week in mild preeclapsia and thrice a week in severe preeclampsia

Fetal Assessment:

The following tests should be carried out at diagnosis:

• Cardiotocography


• Ultrasound for fetal growth and amniotic fluid volume assessment


• Umbilical artery doppler velocimetry.

If the results of all fetal monitoring are normal, cardiotocography need not be repeated more than weekly unless if there is deterioration in maternal condition, vaginal bleeding, abdominal pain, or reduced fetal movement. Repeat ultrasound for fetal growth, amniotic fluid volume assessment or umbilical artery doppler velocimetry is also not required more than every 2 weeks.

Diet should be adequate in proteins; salt restriction is not advised in Preeclampsia.

Anti-hypertensive Therapy

It can be initiated if DBP >100 mm Hg. Lower threshold may be considered if disease has arisen before 28 wks. Aim is to keep DBP between 80–100 mm Hg, and SBP less than 150 mm Hg. In mild PE, it reduces the occurrence of severe hypertension, but there is no benefit in terms of maternal & fetal outcome. In severe hypertension therapy is mandatory to reduce the risk of CVA.

• Tab. Methydopa -250- 500 mg 3-4 times /day.

• Tab. Labetalol-100-200 mg 2-3 /day

• Labetalol: IV regimen: 20 mg stat. If DBP>110 after 20 min, give 40 mg; ↑ to 80 mg & then 80 mg to a total of 220mg. If no response, discuss with senior physicians and anaesthetists.

• Use of ACE inhibitors is contraindicated in pregnant woman

• Nitroglycerine (NTG) drip may be useful in hypertensive crisis: Dose - 50mg in 500ml 5%dextrose, start at 10ml/h, ↑ by 5ml every 10-15‘ till SBP ≈ 140mm Hg

Anticonvulsants

Consider giving intravenous magnesium sulphate to women with severe pre-eclampsia who are in a critical care setting if birth is planned within 24 hours.

Termination of Pregnancy

Mild to moderate PE: Terminate at 34+0 to 36+6 weeks depending on maternal and fetal condition, risk factors and availability of neonatal intensive care.

Severe PE: Terminate at 34 weeks. Induction before 34 weeks may be indicated if:

 severe hypertension develops refractory to treatment

 maternal or fetal indications of worsening condition

Corticosteroid for Lung Maturity

Two doses of betamethasone 12 mg IM 24 hours apart are recommended between 24- 36 weeks.

Intrapartum care In women with severe pre-eclampsia

• Accurate recording of fluid balance (including delivery and postpartum blood loss, Intake/output chart) and Maintenance crystalloid infusion - 85 ml/hour, or urinary output in preceding hour plus 30 ml. Diuretics and CVP monitoring may be required if pulmonary oedema is suspected.

• Measure blood pressure, hourly in women with mild or moderate hypertension and continually in women with severe hypertension. Continue use of antihypertensive treatment during labour.

• Do not routinely limit the duration of the second stage of labour in women with stable mild or moderate hypertension or if blood pressure is controlled within target ranges in women with severe hypertension. Operative birth is recommended in the second stage of labour if severe hypertension has not responded to initial treatment

• Use of Methergine is contraindicated for active management of 3rd stage.

Ceasarean Section is indicated for severe IUGR/ primi remote from term with unfavorable cervix, for fetal distress or other obstetric indications. Thrombo prophylaxis to be considered in severe PIH.

Analgesia & Anesthesia Issues:

• GA Risks: - Aspiration, laryngeal edema, difficult intubation, pulmonary edema/ arrythmias precipitated by pressor response to intubation, neuro-muscular blockade effect of mag sulf.

• Continuous lumbar epidural preferred method of pain relief as well as for cesarean section provided there is no coagulopathy and platelet count is > 50,000/cu mm.

• Need adequate pre-hydration of 1000 cc, Level should be advanced slowly to avoid low BP

Postpartum Care

Women with PE who did not require anti-hypertensives: Measure BP at least four times a day while the woman is an inpatient, at least once between day 3 and day 5 after birth, and on alternate days thereafter until normal. Ask about severe headache and epigastric pain each time blood pressure is measured. Start antihypertensive treatment if blood pressure is ≥ 150/100 mmHg.

Women with PE who took antihypertensive treatment: Measure BP at least four times a day while the woman is an inpatient and every 1–2 days for up to 2 weeks after transfer to community care. Continue antenatal antihypertensive treatment, and reduce it if BP falls below 130/80 mmHg. If a woman has taken methyldopa to treat preeclampsia, stop within 2 days of birth, measure platelet count, transaminases and serum creatinine 48–72 hours after birth.

Discharge the women when there are no symptoms of pre-eclampsia, BP is ≤ 149/99 mmHg, with or without treatment, and blood test results are stable or improving.

All women who have had pre-eclampsia should have a medical review 6–8 weeks after birth to detect those women who still need antihypertensive treatment. Women who continue to have proteinuria (≥1+) a further review is required after 3 months to assess kidney function. Specific investigations like aPLa, LAC and thrombophilia screen may be needed.

Eclampsia

Generalized convulsions occurring after the 20th week of pregnancy with underlying pre-eclampsia

Incidence

Antepartum 40%, Intrapartum 20%, Postpartum 40%. Although seizures may occur as long as 3 weeks postpartum, majority of cases (98%) occur on the first day.

All cases of eclampsia are best managed at situation 2 or 3.

If a woman with eclampsia is seen at situation 1, she should be stabilized with Magsulph and antihypertensives and transferred to higher centre only when stable and with full life support system, to limit maternal and fetal morbidity. Immediate care is needed with airway support, adequate oxygenation, anticonvulsant therapy, and BP control. Delivery of neonate is the only definitive treatment, with Intensive postpartum care.

General Measures:

• Do not leave patient alone

• Call for help and inform consultants - obstetrician & anesthetist on call

• Prevent maternal injury: Place in semi-prone position, guardrails on the bed, padded tongue blade b/w teeth.

• Airway: Maintain patency, start oxygen inhalation, suction of mouth secretions.

• Breathing: Assess, Ventilate as required.

• Circulation: Left lateral tilt, If pulse, BP absent, initiate CPR, call ICU

• After the seizure has ended, a 16- to 18-gauge IV line should be obtained for drawing specimens for laboratory studies and administering fluids

• Attach ECG, automatic BP monitors, pulse oximeter

• Indwelling Urinary catheter - Fluid input / output chart

Treatment and prophylaxis of seizures:

Magnesium sulphate is the anticonvulsant drug of choice. After ABC:

• Loading Dose: 4 g IV over 10-15 minutes Prepared by adding 8 ml of 50% MgSO4 solution to 12 ml of N Saline/ 20 ml of 20% solution

 Maintainance Dose: 92 MgSO4 (50% solution) + 1ml Lidocaine 2% given IM every 4 hrs into alternate buttock

 Monitor the following parameters before giving a repeat dose

- respiratory rate > 16 breaths/minute

- urine output > 25 ml/hour, and

- patellar reflexes are present

• Remember to subtract volume infused from total maintenance infusion volume (85 ml/hour)

• A higher maintenance dose may be required initially to prevent recurrent seizures - consultant must make this decision

• If seizure continues, or if seizures recur, give a second bolus of magnesium sulphate: 2-4 g depending on weight of patient, over 5-10 minutes (2 g if < 70 kg and 4 g if > 70 kg)

• If seizures continue despite a further bolus of Mg sulphate, Diazepam (10 mg IV) or thiopentone (50 mg IV) can be given. Intubation may become necessary in such women. Further seizures to be managed by IPPV & muscle relaxation.

Magnesium Toxicity:

• If urine output < 100 ml in 4 hours withhold Magsulph and review overall management with attention to fluid balance and blood loss

• Absent patellar reflexes: Stop MgSO4 infusion until reflexes return

• Respiratory depression: Stop MgSO4 infusion, Give oxygen via facemask and place in recovery position and Monitor closely

• Respiratory arrest:

Stop MgSO4 infusion, Give Calcium gluconate (10 ml slow IV), Intubate and ventilate.

• Cardiac arrest:

Commence CPR, Stop MgSO4 infusion, Give IV Calcium gluconate*, Intubate and ventilate; If antenatal, immediate delivery

Other Anticonvulsant Drugs

• Phenytoin

- 20 mg/kg diluted in 100ml saline infused at maximum rate of 50 mg/min IV over 15-20mts followed by 100mg IV 8 hrly. It may cause hypotension, arrythmias, local phlebitis, and requires ECG monitoring

• Diazepam

- 10 mg IV at a rate of 1mg/min. It can cause maternal sedation, fetal respiratory depression, hypotonia and ↓ beat-to-beat fetal heart variability

Treatment of Hypertension :

• Reduction of severe hypertension is mandatory to reduce the risk of CVA & further seizures.

• Insufficient evidence to recommend one antihypertensive in preference to another and so the choice of which drug to use should depend on personal preference and availability.

• Labetalol (20mg IV ↑ to 40 and 80mg every 20’ to max. 220mg) It may precipitate fetal distress, thereby necessitates continuous fetal heart rate monitoring.

• NTG drip (5µg/m iv infusion, ↑to max 100µg/m)

Fluid therapy:

• Close monitoring of fluid intake and urine output is mandatory. Fluid therapy should be limited to maintenance crystalloid (85ml/h or urine output in preceding hour plus 30ml) to avoid tissue overload, pulmonary edema & ARDS. Colloids remain in vascular tree and unless used carefully can cause circulatory overload.

Antibiotics:

Inj. Ampiciliin 500 mg x 6hrly IV to prevent infection

Associated Complications:

HELLP syndrome (3%), Disseminated intravascular coagulation (3%), renal failure (4%), ARDS (3%)

Differential Diagnosis -

• Cerebral tumors, Cerebral venous thrombosis, Intracranial hemorrhage

• Drug overdoses, Electrolyte imbalance

• Epilepsy, head trauma, Stroke (ischemic/ non-ischemic)

Monitoring:

• Record BP every 10 minutes. Reduce DBP to 90-100 mm Hg with antihypertensive medication

• Auscultate lungs for aspiration after convulsion ended

• Monitor the neurologic status, urine output, respirations, and fetal status

Laboratory workup:

• CBC, RFT, LFT, Electrolytes, Glucose, PLT, Coagulation profile

• Urinalysis for proteinuria

• Blood gases & Invasive PCWP monitoring may be necessary for accurate fluid management in patients with pulmonary edema or anuria

• USG abdomen may be used to rule out abruptio placentae

• CT scan/ MRI if focal neurological deficits or prolonged coma

Delivery :

• The definitive treatment of eclampsia is delivery.

• Attempts to prolong pregnancy in order to improve fetal maturity are unlikely to be of value.

• However, it is inappropriate to deliver an unstable mother even if there is fetal distress.

• Once seizures are controlled, severe hypertension treated, and hypoxia corrected, delivery can be expedited.

• Vaginal delivery should be considered but caesarean section is likely to be required in primigravidae remote from term with an unfavourable cervix/ deteriorating maternal or fetal condition

• After delivery, high dependency care should be continued for a minimum of 24 hours.

During Post partum period :

• Mag sulf for 24 hrs after delivery or after last fit whichever is later

• Continue Vital monitoring, antihypertensives, antibiotics

• Counsel about next pregnancy

Can it be prevented?

Vigilant ANC & a well-timed delivery may prevent eclampsia, and Magnesium is routinely given to women with severe PE in the expectation that it prevents progression to eclampsia, but fits which occur without warning may be impossible to prevent.

Guidelines Developed Ministry of Health and Family Welfare-

Group Head Coordinater Dr Ashley J D'cruz Narayana Hrudyalya Hospital. Bangalore Dr. Garima Arora Gandhi & Dr. Lavanya.R Department of Obstetrics and Gynaecology Narayana Hrudyalya Hospital. Bangalore Dr. Sharath Damodhar ( HOD, Dept. of Haemotology), Narayana Hrudayalaya Karnataka, Dr.Basavaraju Narasimhaiah, DGO, Tumkur Government Hospital, Karnataka,