Page 65 - PCC14

placed through the internal os, 57.3% vs 43.1%, P1⁄4.0054 (103).
Summary statements:
Thereisfairevidencebasedonsixstudies(twoRCTsand four cohort studies) that embryo transfer catheter place- ment affects implantation and pregnancy rates. (Grade B)
Thereisfairevidencebasedonsevenstudies(threeRCTs and four cohort studies) that placement of the catheter tip in the upper or middle (central) area of the uterine cavity, greater than 1 cm from the fundus for embryo expulsion, optimizes pregnancy rates. (Grade B)
There is insufficient evidence for more specific recom- mendations regarding the positioning of the catheter at the time of embryo transfer. (Grade C)
Does the Time Interval before Withdrawing the Catheter Affect IVF-Embryo Transfer Pregnancy and Live-Birth Rates?
Once the embryo(s) is discharged from the embryo catheter the physician has the option of immediately withdrawing the transfer catheter or pausing before withdrawal of the catheter. A randomized, controlled study of 100 patients (104) compared immediate withdrawal to a 30-second delay and found no difference in pregnancy rates. A follow-up cohort study of 218 patients (105) examined immediate with- drawal compared with a 60-second delay before withdrawal, and similarly found no difference in pregnancy rates based on timing of catheter withdrawal. It can therefore be concluded that a delay in catheter withdrawal after embryo placement does not lead to improved pregnancy rates.
Summary statement:
There is fair evidence based on one RCT and one cohort study to recommend immediate withdrawal of the em- bryo transfer catheter after embryo expulsion. (Grade B)
Is the Presence of Mucus on the Catheter (after It Is Removed) Associated with Pregnancy and Live- birth Rates?
The goal of embryo transfer is to attain a smooth, atraumatic passage of the catheter through the endocervical canal and lower uterine segment. Clinicians have debated whether the presence of mucus on the catheter after the embryo transfer adversely affects IVF success rates.
Seven cohort studies (106–112) showed that the presence of mucus in or on the catheter (once it is withdrawn) does not adversely affect clinical pregnancy rate or live-birth rate. In a cohort study that compared direct embryo transfer with the afterload technique, a higher pregnancy rate, not statistically significant, was found with the afterload technique vs the direct technique. For the latter, more catheters were contam- inated with mucus, which was statistically significant (113). This was the only study that implicated a negative outcome with the presence of mucus contamination after withdrawing the catheter.
Summary statement:
There is fair evidence based on seven cohort studies that the presence of mucus on the embryo transfer catheter, once it is withdrawn, is not associated with a lower clinical pregnancy rate or live-birth rate. (Grade B)
Does the Presence of Blood on the Catheter (once It Is Withdrawn) Make a Difference in Pregnancy or Live-birth Rate?
The presence of blood on the catheter once removed at the time of embryo transfer and its possible implications have been studied often, suggesting an increased interest and concern about blood and embryo transfer techniques. A total of 17 studies (1 RCT, 1 systematic review/meta-analysis, and 15 cohort studies) were evaluated. Many of the cohort studies were performed 10 to 15 years ago. A small RCT (70) compared pregnancy outcomes in patients randomized to em- bryo transfer with the Tomcat catheter (n1⁄432) vs the TDT catheter (n1⁄434). They reported the presence of blood and/or mucus on the catheter as a secondary outcome measurement and found no impact of blood on clinical pregnancy rate and implantation rate. A large cohort study from an Australian database (109) also demonstrated no significant difference on clinical pregnancy rate based on catheter tip contamina- tion (30.2% no contamination, 24% mucus only, 30% blood only, 39.1% mucus and blood, 26.4% much mucus and blood, P1⁄4NS). One systematic review/meta-analysis (114) and six other cohort studies (78, 108, 110, 111, 115, 116) were in agreement.
In contrast to the RCT (70), meta-analysis (114), the recent large Australian cohort study (109), and five other cohort studies showing no adverse association between pregnancy rates and blood on the withdrawn embryo transfer catheter, eight other cohort studies (44, 106, 112, 117–121) demonstrated an opposite finding. A 2002 cohort study of 640 IVF-ICSI cycles showed that clinical pregnancy rate was significantly (P<.01) higher when there was no blood during transfer vs with blood. The OR was 0.54 (0.35–0.84) for diminished pregnancy rate in cycles with blood during embryo transfer vs bloodless (120). In another cohort study (584 consecutive cycles), blood on the catheter was the most important transfer characteristic in predicting implantation rate (P1⁄4.042) and clinical pregnancy rate (P1⁄4.018) (106). The presence of blood on the catheter was associated with decreased clinical pregnancy rate (31.7% blood vs 51.7% no blood, P1⁄4.004; strength of association: P1⁄4.01) or implanta- tion rate (19.5% blood vs 31.3% no blood, P1⁄4.015; strength of association: P1⁄4.04), when only high-grade embryos or blastocysts were transferred (106). There is a suggestion that embryos are more likely to be retained in a catheter when it is contaminated with mucus or blood, but retention of em- bryos has not been associated conclusively with poorer outcomes.
Summary statement:
Given the mixed results of studies, there is insufficient evidence to state conclusively that the presence of blood
Page 58 of 69
889
Fertility and Sterility®
VOL. 107 NO. 4 / APRIL 2017
PRECONGRESS COURSE 14 I BARCELONA, SPAIN – 1 JULY 2018 65