it is a traumatic event that can have psychological consequences for the couples ( 1 ) .
threatened abortion , as demonstrated by vaginal bleeding with or without abdominal cramps , is a common complication of pregnancy .
it occurs in 20 percent of women during early gestation and approximately half of these pregnancies will abort ( 2 , 3 ) .
even if abortion does not follow early bleeding , these fetuses are at increased risk for preterm delivery , low birth weight and prenatal death ( 4 ) .
a number of recent studies suggest that progesterone can reduce pregnancy loss in women with threatened abortion ( 510 ) . by progression of pregnancy ,
the role of insufficient progesterone level declines and uterine structural malformation with or without cervical incompetency is responsible more than hormonal deficit . in this case
, some approaches like cervical cerclage can be effective more than medical interventions ( 11 ) .
progesterone plays a crucial role in the maintenance of pregnancy . in the presence of sufficient progesterone levels during pregnancy
, lymphocytes synthesize a mediator called progesterone induced blocking factor ( pibf ) , which is anti - abortive in mice ( 12 , 13 ) .
besides inducing secretary changes in the endometrium and supporting early pregnancy , it modulates the maternal immune response to prevent fetal rejection and relaxes the uterine smooth muscles ( 14 ) . despite this physiological evidence , which has led to progestogens being used in management of threatened abortion for many years
, there is little data available to support their routine use in this issue ( 15 ) .
the aim of this study was to determine whether progesterone is effective in allowing pregnancy to proceed beyond week 20 in women with threatened abortion .
this clinical trial study was done on 60 pregnant women with threatened abortion from april 2009 to march 2012 at taleghani hospital affiliated to shahid beheshti university of medical sciences .
this trial was a single - blind study , in which the researchers did not have any placebos for the control group and were unaware which patient had received progesterone .
the study was approved by the bioethics committee ( 400.11199/30 may 2012 ) of shahid beheshti university of medical sciences after the approval of the research group in the obstetrics and gynecology department .
verbal consent of all the pregnant women participating in the trial study was received as well .
pregnant women , who had vaginal bleeding until 20 weeks of their pregnancy , were assessed for inclusion .
participants underwent a general and pelvic examination , a pelvic ultrasound and a complete measurement of their blood count . in order to be included in the study , the women were required to have no systemic disease or fever and no loss of conception tissue .
the presence of singleton pregnancy and detection of fetal heart activity , besides gestational age of less than 20 weeks was verified by ultrasound .
women were excluded if they had reaction to cyclogest , multiple gestation , absence of fetus or fetal heart tone , uterine anomaly or fetal anomaly .
participants were divided into two groups ; the control group , which did not undergo any treatment and the case group .
the case group was given 400 mg of vaginal progesterone suppository ( cyclogest , actavis , uk ) each day until their bleeding stop - ped for several days , mostly less than one week .
progesterone in suppository and injection form and in a short time usage did not have any adverse effect on mother or fetus ( 4 , 6 ) .
those who had slight vaginal bleeding received progesterone sup - pository only for 2 days .
however , for those with moderate or severe vaginal bleeding , it continued up to one week .
the sample size was 60 based on p1 = 80% , p2 = 50% expected rate of abortion in threatened abortions , = 0.05 and  = 20% .
both groups consisted of 30 participants and were kept under standard care in terms of hydration and rest .
qualitative and quantitative variables were analyzed statistically by chi square and t - test respectively .
qualitative and quantitative variables were analyzed statistically by chi square and t - test respectively .
a total number of 60 pregnant women , with threatened miscarriage , participated in the study .
all of them were referred to the department of obstetrics and gynecology at taleghani hospital .
the total age range was from 18 to 37 years with a mean value of 274 .
there was no statistically significant difference between the case group and the control group in terms of mothers ages , gestational ages and parity score .
the mean value of mothers ages was 274 years in the case group and 275 years in the control group .
average gestational age was 9 weeks3 days in the case group and 10 weeks3 days in the control groups .
moreover , there were 20 nulliparous women in the case group and 18 in the control group , with the rest being multiparous .
five patients in the case group and nine patients in the control group had moderate to heavy uterine bleeding .
overall , 9 patients in the case group and 7 patients in the control had abdominal cramp with vaginal bleeding , but the outcome of ongoing pregnancy or abortion did not differ in both groups .
the number of abortions in the case group was lower than the control group ( 6 cases , 20% against 10 cases , 33.3% respectively ) . however , the difference was not statistically significant . as demonstrated in table 1 ,
80% of women in the case group and 66.7% of women in the control group had a successful term pregnancy .
approximately 66.7% of patients with successful delivery in the case group and 60% in the control group were nulliparous ( p = 0.592 ) .
moreover , 70% of the patients with successful delivery in the case group and 76.7% of them in the control group had no abdominal cramp ( p = 0.559 ) .
accordingly , neither parity nor abdominal cramp had any effect on the outcome of pregnancy . 
 
this study was conducted in order to assist pregnant women with threatened abortion , since miscarriage is a deeply distressing condition for couples ( 1 ) .
the study demonstrated that the rate of abortion was reduced clinically but not statistically in women treated with progesterone suppository as compared to women who received only supportive care .
these findings support recent studies on women with threatened abortion that have shown a reduction in pregnancy loss with progesterone treatment ( 3 , 710 , 21 ) .
pro - inflammatory cytokines associated with mis - carriage and progesterone- induced blocking factor ( pibf ) had inhibitory effect on immune reaction and shifting of cytokines from type 1 to type 2 cytokines caused an increase in the production of cytokines type 2 ( 22 ) .
pregnancy is often hampered by immunological factors , luteinic and neuroendocrine deficiencies and myometrial hyper - contractility .
this may explain the reduction in abortion in women treated with prophylactic progesterone ( 3 , 6 , 9 , 19 ) .
there are some studies , however , that show insufficient data on the effect of progestogens on threatened miscarriage ( 2 , 5 , 6 , 15 ) . according to one study from el - zibdeh , miscarriage rates were significantly lower in the group treated with dydrogesterone as compared to the untreated group ( 16 ) .
progestogens also have a direct pharmacologic effect by reducing the synthesis of prostaglandins , thereby relaxing uterine smooth musculature and preventing inappropriate contractions that may result in miscarriage and preterm labor pain ( 5 , 1820 ) .
some pregnant women have lower abdominal pain followed by missed period , but if lower abdominal pain is associated with uterine bleeding , it may predict impending abortion . in this study , however , most of the pregnant women had no abdominal pain in either the case group or the control group and the difference between two groups was not statistically significant . a study has shown that the use of progesterone is effective in both pain relief and decreasing the frequency of uterine contractions after 5 days of progesterone usage ( 8) . effect of progesterone on different gestational ages was also evaluated in this study . in gestational age of 8 weeks or less ,
80% of participants in the case group and 50% of participants in the control group had successful delivery .
in gestational age of 8 to 16 weeks , 80% of pregnant women treated with progesterone had successful delivery as compared to the 60% in the control group .
in gestational age of more than 16 weeks , 80% of pregnant women treated with progesterone and 50% of women in the control group had successful delivery .
in previous studies , there has been no report of comparison between case and control groups with respect to different gestational ages .
there are some studies which have reported some problems during the course of pregnancy in women with threatened abortion ( 4 , 16 ) .
however , in this study , all pregnant women who passed their course of threatened abortion had normal term pregnancies .
the study demonstrated that the rate of abortion was reduced in women treated with progesterone , irrespective of their gestational age .
nevertheless , its effect on prevention of abortion was not statistically meaningful , which may be due to the study 's small sample size .
the use of large sample sizes , double - blind and randomized controlled trials are recommended for future studies on this issue .
this article is extracted from the obstetrics and gynecology resident thesis in shahid beheshti university of medical sciences .
 backgroundthreatened abortion is a common complication of pregnancy . in order to prevent miscarriage in the cases with threatened abortion , this study was conducted to determine whether progesterone suppository is effective in allowing pregnancy to proceed beyond week 20 in women with threatened abortion.methodsthis single - blind clinical trial study was done on 60 pregnant women with threatened abortion . 
 pregnant women , who had vaginal bleeding until 20 weeks of their pregnancy , were assessed for inclusion . 
 participants were divided into two groups by random allocation ; the control group , which did not undergo any treatment and the case group . 
 the case group was given 400 mg of vaginal progesterone suppository ( cyclogest ) each day until their bleeding stopped in less than one week . 
 participants were followed up until the end of their pregnancy . 
 the treatment was considered successful if pregnancy continued beyond 20 weeks of gestation . 
 qualitative and quantitative variables were analyzed statistically by chi square and t- test respectively . 
 the p - values of less than 0.05 were considered significant.resultsthere was no statistically significant difference between the case and the control groups in terms of background variables . 
 the number of abortions in the case group ( 6 cases , 20% ) was lower than the control group which had 10 abortions ( 33.3%).conclusionthe study demonstrated that the rate of abortion was reduced in women treated with progesterone suppositories . 
 however , the difference was not statistically significant . 
Introduction
Methods
Statistical analysis
Results
Discussion
Conclusion
Conflict of Interest