In addition, four articles were excluded after full text review as shown in Fig. risk [RR] 1.12; 95% confidence interval [CI] 0.93 to 1 1.34; and value of less than 0.05 was Catharanthine hemitartrate considered to be statistically significant. Results Study characteristics and quality assessment The literature selection process is presented in Fig.?1. In total, 380 articles were identified in the initial database search. After screening of abstracts and titles, 372 apparently irrelevant articles were excluded because they did not meet the inclusion and/or exclusion criteria. In addition, four articles were excluded after full text review as shown in Fig. ?Fig.1.1. Eventually, four eligible studies [14, 17C19] including 621 patients were considered for this meta-analysis. Of these patients, 309 and 312 were classified into Catharanthine hemitartrate the LE and LOD groups, respectively. The process of randomization was sufficient in all studies [14, 17C19]. Allocation sequence concealment was implemented and reported in only two studies [14, 19] and was unclear in the remainder [17, 18]. The participants and researchers were distinctly masked to the intervention in only one study [19], however, most of the remaining cases masking was unclear in the remaining three studies [14, 17, 18]. Both the characteristics of the studies included in the meta-analysis and the quality assessment of the included RCTs are presented in the supplemental material (Tables?1 and ?and2,2, respectively). Open in a separate window Fig. 1 Flowchart of study selection of the randomized controlled trials (RCTs) Table 1 Characteristics of the studies included in the review letrozole, laparoscopic ovarian drilling Table 2 Quality assessment of the included studies thead th rowspan=”1″ colspan=”1″ Author (year) /th th rowspan=”1″ colspan=”1″ Random sequence generation /th th rowspan=”1″ colspan=”1″ Allocation concealment /th th rowspan=”1″ colspan=”1″ Blinding of participants and personnel /th th rowspan=”1″ colspan=”1″ Blinding of outcome assessment /th th rowspan=”1″ colspan=”1″ Incomplete outcome data /th th rowspan=”1″ colspan=”1″ Selective reporting /th th rowspan=”1″ colspan=”1″ Other bias /th /thead Abu Hashim (2010)YesYesYesYesYesNoYesLiu (2015)YesNoNoNoNoNoYesIbrahim (2017)YesNoNoNoNoYesYesAbdellah (2011)YesYesNoNoNoNoYes Open in a separate window Ovulation rate Three studies [14, 17, 19] evaluated the ovulation rate. As shown in Rabbit Polyclonal to KCY Fig.?2a, there was no statistically significant difference between the LE group and LOD group when comparing ovulation rates (RR 1.12; 95% CI 0.93 to 1 1.34; em P /em ?=?0.12, I2?=?90%, 541 patients). Open in a separate window Fig. 2 Letrozole (LE) versus laparoscopic ovarian drilling (LOD): rates of ovulation and pregnancy. (a) Ovulation rate. (b) Pregnancy rate. (c) Live birth rate Pregnancy rate As presented in Fig. ?Fig.2b,2b, all four of the studies [14, 17C19] including 621 patients reported data on pregnancy rate. There was a statistically significant increase in the pregnancy rate in the LE group when compared with the LOD group (RR 1.21; 95% CI 0.95 to 1 1.53; em P /em ?=?0.12, I2?=?0%). Live birth rate The three studies [14, 17, 19] that evaluated live birth rate included 541 patients. As shown in Fig. ?Fig.2c,2c, there was no statistically significant difference when comparing LE with LOD in these studies (RR 1.27; 95% CI 0.96 to 1 1.68; em P /em ?=?0.09, I2?=?19%). Abortion rate As shown in Fig.?3a, four studies [14, 17C19] including 621 patients reported on abortion rate. There was no significant difference in the abortion rate between LE versus LOD treatment in the Catharanthine hemitartrate studies (RR 0.7; 95% CI 0.3 to 1 1.61; em P /em ?=?0.40, I2?=?0%). Open in a separate window Fig. 3 Letrozole (LE) versus laparoscopic ovarian drilling (LOD): abortion rate and endometrial thickness at human chorionic gonadotrophin (HCG) injection. (a) Abortion rate. (b) Endometrial thickness at HCG injection Endometrial thickness Two studies [14, 17] reported the endometrial thickness on the day of HCG injection. As shown in Fig. ?Fig.3b,3b, there was no obvious heterogeneity across the studies (I2?=?0%, em P /em ?=?0.48), and thus a fixed-effects model was used. The meta-analysis revealed a statistically significant increase in the endometrial thickness in the LE group relative to the LOD group (SMD 1.10; 95% CI 0.85 to 1 1.35; em P /em ? ?0.00001, Fig. ?Fig.33b). Publication bias A funnel plot was generated to qualitatively evaluate publication bias. The funnel plot for the outcome pregnancy rate shown in Fig.?4 is almost symmetrical, indicating that there was no potential publication bias in the four included studies. Open in a separate window Fig. 4 Funnel.