cesarean scar pregnancy ( csp ) is a rare , albeit life - threatening , type of ectopic pregnancy in which the embryo implants in an iatrogenic cesarean scar left in the uterus . csp is a distinct entity compared with other types of ectopic pregnancies because it never occurs in the first pregnancy and it never occurs in a woman with no previous cesarean delivery . the reported rate of csp is 1 in 2,000 and accounts for 6% of ectopic pregnancies among women with a prior cesarean delivery . an exact and early diagnosis of csp is very important for prognosis because it can result in life - threatening conditions and even maternal death . here , we describe 4 women with csp and discuss their clinical presentations , diagnoses , and various management options , especially medical management of csp , along with the published literature . four women with a suspicion of csp or cervical pregnancy were referred to our hospital between august 2013 and january 2014 . all the patients had detailed ultrasonographic ( usg ) assessment and measurement of serial serum beta human chorionic gonadotropin (  - hcg ) levels . the benefits and potential risks of methotrexate ( mtx ) treatment were explained , and written informed consents were obtained . before the treatment , liver and kidney functions were evaluated . the age , parity , usg assessment , serum  - hcg level , management , and follow - up period of the 4 patients are summarized in table 1 . none of the women had any clinical symptoms such as vaginal bleeding and lower abdominal pain . the size of the gestational sac and the  - hcg levels were followed until the gestational sac shrank and the  - hcg level reached < 5 miu / ml ( defined as undetectable level ) . summary of the characteristics of the 4 patients treated with different conservative treatment methods at the time when the procedure was performed . usg : ultrasonography ; cs : cesarean section ; crl : crown - rump length ; ega : estimated gestational age ; fka : fetal cardiac activity ; -hcg : beta human chorionic gonadotropin ; gs : gestational sac ; mtx : methotrexate ; lcv : leucovorin ; kcl : potassium chloride the usg assessment of the 4 patients revealed common findings : a well defined gestational sac with or without a crown - rump length , a closed internal cervical ostium , a normal cervical length , and an empty uterus ( figure 1 ) . transvaginal ultrasonography of the cesarean scar pregnancy of the 4 women in the study is depicted here . the midline sagittal images demonstrate gestational sacs ( small arrows ) implanted at the isthmic region between a closed cervix ( star ) and an empty uterine cavity ( large arrows ) and the anatomical location of previous cesarean scars ( a - d ) . a crown - rump length is distinguished inside the gestational sac ( a , b ) . in all the pregnancies , moreover , 3 of the women had a fetal cardiac activity . since these clinical ( high serum  - hcg levels ) and usg findings were compatible with csp , further evaluations were considered unnecessary . systemic mtx treatment with a single - dose weight - based protocol ( 1 mg / kg intramuscular ) was given . serum  - hcg levels were checked before treatment and then on the 4th and 7th days of treatment . in the first and second women , the  - hcg levels increased from day 4 to day 7 from 128.318 to 132.493 miu / ml and from 30.213 to 34.600 miu / ml , respectively ( figure 2 ) . changes in serum beta human chorionic gonadotropin (  - hcg ) levels of the 4 patients with cesarean scar pregnancy before and after the medical treatment are illustrated here . the values on the curve represent the  - hcg measurements at each given week . since the expected serum  - hcg level decrease was not achieved , multi - dose mtx and leucovorin were administered consecutively ( in 8 days : 4 days of mtx [ 1 mg / d ] and 4 alternative days of leucovorin [ 0.1 mg / d ] ) . after the last dose , the first and second patients  - hcg levels were 62.514 miu / ml and 5.542 miu / ml , respectively . the  - hcg levels reached < 5 miu / ml 14 and 11 weeks after the first day of medical treatment . the complete remission of the gestational sac diameter took approximately 6 months . in the third patient , a single - dose systemic mtx ( 1 mg / kg ) was administered , and the serum  - hcg level increased to 9105 miu / ml on day 4 and remained elevated at 9225 miu / ml on day 7 ( figure 2 ) . a repeated usg scan revealed a stable intramural hypoechogenic gestational sac in the lower uterine segment . thereafter , the  - hcg level decreased to 5026 miu / ml and 2770 miu / ml on days 4 and 7 , respectively . eight weeks after the initial mtx dose , the  - hcg level was undetectable and usg revealed a stable 2.53.82.7 cm heterogeneous mass in the lower uterine segment . the mass eventually resolved 18 weeks after the treatment . in the fourth patient , after extensive counseling , the pregnancy was terminated through a transvaginal usg - guided injection of potassium chloride ( 0.1 nmol ) into the fetal cardiac cavity with the resultant cessation of the cardiac activity , followed by the administration of 50 mg of mtx into the gestational sac . the serum  - hcg level decreased to 49.003 miu / ml on day 4 and 8.640 miu / ml on day 7 . eight weeks after the injection , the  - hcg level reached the undetectable level . a follow - up usg showed the resolution of the gestational sac after 19 weeks . none of the patients experienced any adverse effects related to the treatment or reported any unexpected vaginal bleeding during the follow - up . their regular menstrual cycles started within 1 month after their  - hcg levels decreased to < 5 miu / ml . the rate of csp is expected to rise in the future due to the increasing number of cesarean sections . however , the ideal treatment protocol is still unknown . the reasons for the ectopic implantation of the conceptus into the cesarean scar as well as its diagnosis and treatment need further evaluation . jurkovic et al . hypothesized that a microscopic defect or the microtubular tract in the cesarean scar might be related to csp by a leading invasion of the conceptus into the myometrium . more than half of all cases of csp were in women with 1 prior cesarean delivery . the clinical manifestations of csp range from no symptoms to acute - onset lower abdominal pain , vaginal bleeding , and even hypovolemic shock . in a review of 57 patients with csp , 36.8% of the women were asymptomatic , 38.6% presented with painless vaginal bleeding , and only a minority ( 24.6% ) presented with abdominal pain . all of our patients were asymptomatic and referred to our hospital as a result of suspicious usg examinations . magnetic resonance imaging and hysteroscopy may be used for further evaluation of pregnancy location , but these are not compulsory for the diagnosis . in our patients , several treatment options for csp such as expectant , medical , and surgical management have been proposed . the expectation in expectant management is that the conceptional material will be reabsorbed and/or expelled by itself against the risk of uterine rupture and hemorrhage . medical management is systemic and is done via a local administration of mtx , potassium chloride , or a combination of these agents by laparoscopic or usg - guided injections . several surgical options have been suggested such as uterine artery embolization , hysteroscopy , and d&c . myometrial wedge excision and hysterectomy may also be needed when there are life - threatening clinical presentations . . showed that uterine rupture with severe hemorrhage occurred in half of the women who were only followed up without treatment . in a hemodynamically stable patient , medical or surgical options may be considered with the aim of eliminating the gestational sac and retaining fertility . the administration of local or systemic mtx has shown high success rates . a single intramuscular dose of 50 mg / m of mtx can be used for csp with a gestational age of less than 68 weeks without fetal cardiac activity . in some reviews , it is mentioned that systemic treatment with mtx is successful if the patient s  - hcg level is < 5000 miu / ml ; nevertheless , additional or alternative treatment interventions are necessary when the  - hcg level is > 6000 miu / ml . in our first 3 patients , since a single - dose mtx treatment was not adequate , complete remission was obtained with complementary medical treatment . it can be debated whether systemic mtx is the treatment of choice . due to the impaired vascularization of this fibrous tissue for this reason , some investigators have advocated a local injection of mtx into the gestational sac . four of these cases were successfully treated with local injections of mtx and potassium chloride . in our fourth patient , after the local injection of potassium chloride and mtx , complete remission was obtained within 8 weeks . in 3 of our 4 patients , the serum  - hcg levels initially increased after the first systemic mtx treatment but after the complementary medical treatment , they showed a steady decline . in contrast , local injections of potassium chloride and mtx caused an immediate decline in the serum  - hcg levels ( figure 2 ) . the serum  - hcg level is a good marker for following the response of patients to mtx treatment . although there are no guidelines on the optimal follow - up , it is recommended to measure the  - hcg level weekly until it reaches < 5 miu / ml . the decrease in the  - hcg levels and the shrinkage of the csp mass were found to be inconsistent . furthermore , the  - hcg levels reached the undetectable level within 814 weeks and the remission of the conceptions took a minimum of 18 weeks . based on this limited number of cases , it seems that csp should be treated conservatively even if there are visible fetal cardiac activity , fetal poles , large gestational sacs , and high initial  - hcg levels . although the complete remission of the lesion takes a relatively long time , medical management via a noninvasive approach and follow - up should be tried as the first choice of therapy .
cesarean scar pregnancy ( csp ) is a rare , but life - threatening type of ectopic pregnancy . 
 an exact and early diagnosis of csp is very important for prognosis . 
 the aim of the present study was to describe 4 women with csp and discuss their clinical presentations , diagnoses , and various management options along with the published literature . 
 four women with a suspicion of csp or cervical pregnancy were referred to our hospital between august 2013 and january 2014 . 
 all the patients were counseled about medical management options . 
 after the treatment , serum beta human chorionic gonadotropin (  - hcg ) levels were followed weekly until they reached < 5 miu / ml . all the patients were diagnosed at the first trimester , with the average gestational age of 6.40.9 weeks . 
 treatment was systemic methotrexate ( mtx ) treatment in 3 of the 4 women , requiring no further intervention . 
 the remaining 1 woman was treated with an intragestational administration of mtx . 
 the mean time passed until  - hcg reached < 5 miu / ml was 10.22.9 ( range , 814 ) weeks , and the mean time passed until the gestational sac resolved was 21.53.5 ( range , 1825 ) weeks . 
 based on this limited number of case - series experience , it seems that csp should be treated conservatively even if there are visible fetal cardiac activity , fetal poles , large gestational sacs , and high initial  - hcg levels . 
 although the complete remission of the lesion takes a relatively long time , medical management via a noninvasive approach and follow - up should be tried as the first choice of therapy .