Two groups of unexplained recurrent spontaneous abortion, each included 65 participants.
scheduled randomly into; the study group received Sildenafil Citrate and Placebo group. The
intervention started from day 21-23 of the cycle preceding spontaneous pregnancy and
continued till the 12th-week of gestation.
The primary outcome measure was the difference in the live birth between both groups.
Secondary outcome measures were the differences between both groups regard pulsatility index
(PI) and resistance index (RI), a number of take-home babies, the reported side-effects of
treatment and the pregnancy-related complications.