Effects of transdermal nitroglycerin on impedance to flow in the uterine, umbilical, and fetal middle cerebral arteries in pregnancies complicated by preeclampsia and intrauterine growth retardation

OBJECTIVE: We studied whether transdermal nitroglycerin, a donor of nitric oxide, affects uterine, umbilical, and fetal cerebral blood flow in pregnancies complicated by preeclampsia and impaired uteroplacental blood flow. STUDY DESIGN: Seventeen patients with preeclampsia were treated with a nitroglycerin patch, 10 mg per 24 hours, for three consecutive days between 28 and 36 weeks' gestation. The uterine, umbilical. and fetal middle cerebral artery pulsatility index and resistance index were assessed by color Doppler ultrasonography before the start of treatment, daily during treatment, and on the first 2 days after the removal of the last patch. RESULTS: The nitroglycerin patch caused a significant fall in the mean uterine pulsatility index and resistance index that reached its maximum (18% +/- 4% and 17% +/- 3%, respectively, from baseline) on the last treatment day. After the removal of the last patch, uterine pulsatility index and resistance index rose to the pretreatment value within 12 hours. No significant changes in umbilical or middle cerebral artery pulsatility index and resistance index were observed during treatment. Maternal mean arterial pressure fell from 122 +/- 8 to 117 +/- 7 mm Hg (P = .05). CONCLUSION: Transdermal administration of nitroglycerin may offer a potential for treatment for patients with preeclampsia who have increased uteroplacental impedance.