Background: There is no clear evidence that any intervention improves the growth of growth limited fetuses in healthy pregnant women. In limited, randomized trials, a variety of therapies have been tested, including maternal nutritional supplementation, interventions to enhance blood flow to the placenta, such as low-dose aspirin, bed rest, and anticoagulation. The use of nitric oxide (NO) donors such isosorbid mononitrate appeared promising and was being researched.
Objective: Evaluation of the efficacy and tolerability of isosorbide mononitrate in reducing umbilical artery Doppler resistance index.
Methods: This randomized controlled trial included 46 pregnant women who had early onset fetal growth restriction. They were randomly assigned into two groups were group A received Isosorbide-5-mononitrate (Imdur®, 30 mg) and group B received Osteocare ®. Both were taken twice daily for 4 to 6 weeks them umbilical artery Doppler resistance index, fetal growth was compared before and after treatment.
Results: Mean umbilical artery Doppler resistance index was statistically significant improved in isosorbide mononitrate group 0.81 ± 0.02 versus 0.75 ± 0.05, before and after treatment respectively with a mean decrease of 0.06. In the isosorbide mononitrate group, the mean EFW is 1113.22 gm before treatment that is increased to 1419.78 gm after treatment, showing an increase in weight by 27.538 %.  Also, the mean gestational age at delivery was statistically non-significant difference between the two groups where in group A it was 36.75 weeks ± 0.8 while in group B 36.25 weeks ± 0.95.
Conclusion: NO donor plays no role in the therapy of FGR with minor Doppler alterations and maternal side effects. It had a minor positive effect on the umbilical artery Doppler and placental circulation.