الفهرس 
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Abstract
According to ACOG guidelines, a fetus with intrauterine growth restriction (IUGR) is fetus with an estimated weight less than the 10th percentile for gestational age. With a prevalence of the 5–8%in the general population, IUGR can complicate 10%to15% of all pregnancies.
IUGR represents the second cause of perinatal mortality, after prematurity, and it is related to an increased risk of perinatal complication as hypoxemia, low Apgar scores, and cord blood acidemia, with possible negative effects for neonatal outcome.
The conversion of spiral arteries into utero-placental artery plays a basic role in the establishment of the physiology of placental blood supply. The reduced utero-placental blood flow due to inadequate trophoblastic infiltration of placental vascular bed can be the cause of variety of pregnancy complications as FGR and preeclampsia.
Myometrial small arteries from pregnancies complicated by FGR show increased vasoconstriction and reduced endothelium-dependent relaxation compared with that seen in normal pregnancy. The decreased utero-placental flow suggested by abnormal uterine artery Doppler in a significant number of women whose pregnancies are complicated by FGR may be a direct result of inappropriately increased vasoconstriction/ reduced endothelium-dependent relaxation.
The management of pregnancies complicated by FGR is currently limited to fetal surveillance, usually by Doppler ultrasound of feto-placental circulation, to allow timing of delivery, such that the pregnancy can be prolonged to gain maximum fetal maturity without exposing the fetus to an excessively adverse in utero environment. Summary and C o nclusion 87
Reduced flow and increased resistance in uterine and umbilical arteries, indicative of reduced utero-placental flow in pregnancies with fetal growth restriction, has been documented by non-invasive Doppler ultrasound velocimetry. Fetal brain perfusion in pregnancies with fetal growth restriction shows clear regional variations, which changes with progression of hemodynamic deterioration.
Sildenafil citrate is the PDE5-specific inhibitor that enhances NO mediated relaxation in small myometrial arteries isolated from women with pregnancies complicated by FGR. The rationale behind this hypothesis stems from the similarities between the pathophysiologies associated with preeclampsia and FGR.
PDE5 inhibitor sildenafil citrate limits the effects of vasoconstrictors in both normal pregnancy and FGR. A similar phenomenon has been suggested in the peripheral vasculature where sildenafil displays the characteristics of a mild NO donor; however, the major effects of sildenafil have been clearly demonstrated to be primarily a result of increases in cytosolic GMP.
In this current study, we selected a group of pregnant women (54) whose pregnancy complicated by FGR and associated with abnormal utero-placental Doppler indices and they divided in two group one received sildenafil and the other received the placebo to test the hypothesis that can sildenafil improve utero-placental blood flow which later improve fetal outcome.
Sildenafil citrate was given to these women to examine uterine blood flow and Doppler indices (UTA-UA-MCA) of fetal well-being before and 2-hours after drug administration. We concluded that oral sildenafil citrate in a dose of 50 mg is capable of improving utero-
placental perfusion in pregnancies complicated by FGR when compared to placebo.
In our study two hours following sildenafil ingestion, 2 patients expressed headache, 4 reported flushing and 1 had nausea but no adverse reactions in the placebo group.
Umbilical artery Doppler has been the mainstay for diagnosing placental insufficiency for 2 decades. Therefore, we measured all Doppler indices of the umbilical artery because evidence showed that umbilical artery Doppler can be used to distinguish between the high-risk small fetus that is truly growth-restricted and the lower-risk small fetus.
The CPR was a better predictor of FGR and adverse perinatal outcome than either the MCA PI or UA PI alone, with a high specificity and PPV. In early-onset FGR, CPR becomes abnormal earlier than does the MCA-PI. So CPR is an earlier and more sensitive predictor of adverse outcome than either the MCA or UA alone, both in severe and in mild forms of FGR.
In this current study before treatment there were no significant differences in the umbilical artery (UA) Doppler indices between both treatment groups. Two hours later when sildenafil citrate or placebo was given according to treatment assignment, patients in the sildenafil group showed significant improvement in all measured umbilical artery Doppler indices. These results were in-line with the results of Dastjerdi et al., (2012) who studied the effect of sildenafil on utero-placental perfusion in growth restricted fetuses and showed that the means (95% CI) of the umbilical artery pulsatility index (PI) and systolic/diastolic ratio (S/D) significantly decreased 2 hours after sildenafil ingestion as compared to the placebo group.