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Management of Pre Eclampsia

By: Dr. D.S. Merchant • The definitive treatment of pre eclampsia is delivery to prevent development of maternal or fetal complications from disease progression.
• Mild pre-eclampsia — At term, women are induced if there are no contraindications to vaginal birth. This minimizes the risk of progression to severe disease and its complications -- There is no reason to delay induction of women who are at least 37 weeks of gestation and have a favorable cervix (Bishop score greater than 6).
• Hospital Admission -- Close maternal monitoring upon diagnosis is important for disease severity and the rate of progression. Hospitalization is useful for making these assessments & facilitates rapid intervention in the event of fulminant progression to eclampsia, hypertensive crisis, abruptio placenta, or HELLP syndrome.
• Lab Follow up -- platelet count, serum creatinine, serum ALT and AST should be repeated once or twice weekly.
• Assessment of fetal well-being & fetal growth – Ultrasound Doppler and Biophysical profile.
• Antenatal corticosteroids -- to promote fetal lung maturity should be administered to women less than 34 weeks of gestation.

Expectant Management of Pre Eclampsia:

In women with severe preeclampsia remote from term, the decision to continue pregnancy beyond that interval required for the administration of corticosteroids depends upon daily maternal and fetal assessment with continual review of the ongoing risks of conservative management versus the benefit of further fetal maturation. Such women should be cared for in a hospitalized setting and by, or in consultation with, a maternal-fetal medicine specialist.

• Hospitalize until delivery.
• Keep the patient at bed rest, except for bathroom privileges.
• Monitor blood pressure every 2 to 4 hours while awake.
• Assess maternal symptoms every 2 to 4 hours while awake.
• Strict recording of fluid intake and urine output.
• Complete blood count, electrolytes, and liver and renal function tests twice weekly.
• Antenatal corticosteroids if not previously given.
• Regular assessment of fetal wellbeing.
• Elective delivery after 34 weeks.

Management of Pre Eclampsia:

• Sodium restriction and diuretics have no role in routine therapy.
• L-arginine supplementation lowered blood pressure or improved kidney function in pre eclamptic women. Effect of L-arginine therapy on the glomerular injury of preeclampsia:
--- a randomized controlled trial Hladunewich MA; Derby GC; Lafayette RA; Blouch KL; Druzin ML; Myers BD Obstet Gynecol. 2006 Apr;107(4):886-95
• Anti Hypertensive Treatment -- initiating antihypertensive therapy in pre-eclamptic/eclamptic women when the systolic blood pressure is >150 mm Hg & diastolic >100 mm Hg.
• Acute Therapy:
• Labetalol – Intermittent or continuous infusion fall in blood pressure begins within 5 to 10 minutes and lasts from 3 to 6 hours.
• Hydralazine -- The fall in blood pressure begins within 10 to 30 minutes and lasts from 2 to 4 hours.
• Calcium channel blockers – Nifedipine & Nicardipine.
• Diazoxide – used when BP control is not archived with Labetalol & Hydralazine

Drugs contraindicated in pregnancy:
• Sodium Nitroprusside
• ACE Inhibitors
• ARB’s

Target blood pressures:
• Systolic b/w 130 to 150 mmHg
• Diastolic b/w 80 to 100 mm Hg

Breastfeeding mothers:
Beta-adrenergic blockers & calcium channel blockers enter breast milk; but considered "compatible" with breastfeeding by the American Academy of Pediatrics.
ACEi & ARB’s are generally avoided during lactation in the neonatal period. Diuretics reduces milk volume.

Effects of BP Control on Fetus:
A 10 mmHg fall in mean arterial pressure was associated with a 176 g decrease in birth weight. This effect was unrelated to the type of hypertension or choice of medication.
Most experts agree that severe hypertension should be treated to prevent maternal vascular complications. However, there is no consensus as to the optimal blood pressure threshold for initiating therapy. We initiate antihypertensive therapy in adult women at systolic pressures between 150 and 160 mm Hg and diastolic blood pressures between 100 and 105 mm Hg.

Complications of Pre-eclampsia:

Outcome measure Normal blood pressure, (percent) Mild preeclampsia (percent) Severe preeclampsia (percent)
Maternal
Outcome measure, Normal blood pressure, (percent), Mild preeclampsia (percent), Severe preeclampsia (percent)
Maternal
Liver dysfunction, 0.2, 3.2, 20.2
Kidney dysfunction, 0.3, 5.1, 12.8
Placental abruption, 0.7, 0.5, 3.7
Induced labor, 12.1, 41.5, 58.7
Cesarean delivery, 13.3, 30.9, 34.9
Delivery <34 weeks, 3.2, 1.9, 18.5
Fetal or neonatal
Growth restriction, 4.2, 10.2, 18.5
Admission to NICU, 12.9, 27.3, 42.6
Respiratory difficulty, 3.8, 3.2, 15.7
Brain hemorrhage, 0.2, 0.5, 0
Fetal death, 0.9, 0.5, 0.9
Neonatal death, 0.5, 0.5, 0.9

Adapted from data in Hauth, JC, Ewell, MG, Levine, RJ, et al. Obstet Gynecol 2000; 95:24.

Diagnosis of IUGR:

• Clinical examination
• Ultrasound biometry
• Uterine artery doppler studies
• Computerized cardiotocography
• Biophysical profile score

Clinical Examination:
- Abdominal palpation: has limited diagnostic accuracy (detects 30% cases of FGR)
- Sympyhseal fundal height in cms: approximates the number of gestational weeks (after 20 weeks)
- Sensitivity is reported from 60-85%

Ultrasound Assessment:

This includes:
- Fetal anatomic survey (16 to 20 weeks)
- Amniotic fluid volume
- Percentile ranks of fetal size measurement
- Growth interval since last study (32-34 weeks)
- Assessment of feto-placental unit with Doppler.

Ultrasound Findings:

• Biparietal diameter/ Head circumference
• Abdominal circumference
• Transverse cerebellar diameter
• Cephalic index
• FL to HC ratio
• Estimated fetal birth weight
• AC and EFW are the most accurate diagnostic measurements to diagnose FGR
RCOG Guidelines 2002

Ultrasound Doppler Studies:

• Dopplers give us information on vascular
resistance and on the blood flow.

• The use of Doppler ultrasound in high risk pregnancies appears to improve a number of obstetric care outcomes and helps to reduce perinatal deaths.

Doppler Parameters:

Commonly used parameters are:

• Systolic to diastolic ratio=
systolic peak velocity/ diastolic peak velocity
• Resistance index (Pourcelot index) =
systolic - end diastolic peak velocity/systolic peak velocity
• Pulsatility index (Gosling index)=
systolic - end diastolic peak velocity/ time averaged maximum velocity
• End- diastolic flow

Common vessels for doppler studies include:
• Uterine artery
• Umbilical artery
• Middle cerebral artery
• Venous dopplers (including ductus venosus, umbilical vein, IVC)

Uterine Artery Doppler:

• Uterine artery doppler is used in the prediction of IUGR.
• Pathological features include:
– elevation of uterine artery indices/ no fall in Resistance Index in mid trimester.
– persistence of early diastolic notch.
– Detection rates are better for severe than for mild disease.
– Detection rates 80-90 % for early onset pre-eclampsia while 41-45% for pre-eclampsia at any gestational age.

Umblical Artery Doppler:

• Umbilical arterial doppler waveforms reflect vascular resistance therefore provides information on downstream distribution of blood supply.

• Changes in blood flow resistance relate to vascular structure (placental histology) & vascular tone.

• Abnormal vascular tone as well as obliteration of fetal villous vessels raises umbilical artery Doppler resistance.

Ultrasound Obstet Gynecol 2004
Obstet- Gynecol Surv 2004
Middle Cerebral Artery Doppler:

Elevated placental blood flow resistance and impaired trans placental gas
Transfer

Increased venous shunting across ductus venosus

Increase proportion of umbilicus venous blood that bypasses the liver & reaches
left side of the heart through foramen ovale

Increased elevation of right ventricular afterload (placental resistance) forces
Redistribution of cardiac output towards the left ventricle and the LVO

Increase blood supply to brain Increase blood supply to heart

Tests for fetal well being:

• These include
– CTG
– Biophysical profile

• Reduced variability or decelerations is associated with increased peri natal morbidity and mortality

• Chronic fetal compromise is associated with decreased fetal body and breathing movements on BPP

Complications of IUGR:

• Congenital anomalies
• Hypoglycemia
• Hypothermia
• Respiratory distress
• Mental retardation
• Meconium aspiration
• Polycythemia
• Jaundice

Article Source: http://www.lifeweightloss.com

Dr. Syed Mujtaba H. Bilgrami, Resident Family Medicine (AKUH). He has written on a range of related issues as pregnancy planning, Pre Eclampsia and Pre Pregnancy stage.

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