Reversed End-Diastolic Flow

Reversed end diastolic flow is retrograde blood flow in the umbilical artery during diastole on Doppler. It indicates near complete obliteration of the placental small vessels and severe fetal compromise. It matters because it carries a very high risk of fetal acidosis, stillbirth and neonatal death, and delivery is usually needed within days.

• Often seen with severe early onset growth restriction.
• Risk factors: severe preeclampsia, antiphospholipid syndrome, chronic hypertension, kidney disease.
• Rapid deterioration is possible within 24 to 48 hours.

Women may have reduced or absent fetal movements, hypertension, proteinuria and a small fundal height, or may be asymptomatic. The fetus often has oligohydramnios.

• Very small abdomen for gestation.
• Low or absent liquor.
• Differential diagnosis: technical artefact (fetal heart rate below 100 beats per minute or above 160 beats per minute, probe pressure), chromosomal abnormality, severe congenital infection, fetal anomaly.
• Complications: stillbirth, fetal acidosis, extreme preterm birth, intraventricular haemorrhage, necrotising enterocolitis, cerebral palsy, neonatal death.

The approach is confirmation by repeat Doppler with assessment of fetal acid base risk.

• Umbilical artery Doppler repeated within 12 to 24 hours in a free loop at normal fetal heart rate; confirm reversed diastolic flow over several cycles.
• Ductus venosus Doppler (absent or reversed a wave), middle cerebral artery Doppler, deepest pocket, estimated fetal weight.
• Cardiotocography daily or twice daily; computerised short term variation below 3.5 ms before 32 weeks where available.
• Maternal: blood pressure, urine protein to creatinine ratio, platelets, liver enzymes, creatinine, antiphospholipid antibodies.

The principle is delivery by caesarean section at 30 to 32 weeks, or at once if the ductus venosus or cardiotocography is abnormal.

• Supportive: admit to a facility with neonatal intensive care; left lateral rest; continuous or twice daily cardiotocography; Doppler every 1 to 2 days; blood group and cross-match; counselling about viability and prognosis before 26 weeks.
• Pharmacological: betamethasone 12 mg IM twice, 24 hours apart, from 24 weeks to 34 weeks and 6 days (delivery 24 to 48 hours after the first dose where the fetus is stable); magnesium sulphate 4 g IV over 20 minutes then 1 g per hour until delivery for 24 hours at most before 32 weeks (stop for absent patellar reflexes, respiratory rate below 12 per minute or urine below 30 mL per hour, with calcium gluconate 1 g IV over 10 minutes for toxicity); labetalol 20 mg IV then 40 mg, 80 mg and 80 mg at 10 minute intervals (maximum 220 mg) or nifedipine modified release 30 to 60 mg oral once daily (maximum 120 mg) for blood pressure above 160/110 mmHg; oxytocin 10 IU IM at birth.
• Procedures: caesarean section at 30 to 32 weeks; immediate delivery for abnormal ductus venosus, pathological cardiotocography, absent fetal movements or maternal deterioration; no induction.
• Special groups: severe preeclampsia needs magnesium sulphate for 24 hours after birth; newborns need warmth, kangaroo mother care, feeding within 30 minutes, haematocrit, and glucose checks at 2 hours, with glucose below 2.6 mmol/L treated by dextrose 10 percent 2 mL/kg IV over 10 minutes then 80 mL/kg per day.
• Red flags: abnormal ductus venosus, pathological cardiotocography, bradycardia, absent fetal movements, severe hypertension, abruption.
• Follow-up: Doppler every 1 to 2 days; cardiotocography daily; neonatal intensive care follow-up with developmental review at 2 years.