Page 63 - PCC14

50 fresh cycles found no statistically significant difference between ultrasound-guided and clinical touch transfers (51). In addition, a cohort study showed that the pregnancy rate was equivalent in 241 embryo transfers performed with and without ultrasound (52). Two underpowered RCTs showed a trend toward a benefit of TA ultrasound guidance that did not reach statistical significance (53, 54). Two RCTs showed no benefit of TA ultrasound guidance (55, 56).
The level of difficulty of embryo transfer has also been the subject of investigation. One RCT showed that ultrasound guidance offered no improvement if a mock transfer was per- formed and found to be easy (57), while another showed no improvement if the uterine cavity length had previously been recorded prior to embryo transfer (58). One cohort study suggested that ultrasound prior to embryo transfer helped identify potentially difficult transfers (59), while another sug- gested that tactile technique was not as reliable as ultrasound for confirmation of catheter placement (60). In cases of diffi- cult embryo transfer, two studies found benefit with ultra- sound guidance (43, 61).
Limited centers have utilized transvaginal (TV) ultra- sound for embryo transfer (62–65). A few studies have compared TA and TV ultrasound guidance for embryo transfer. One study found that TV guidance improved patient comfort relative to TA ultrasound due to the lack of bladder filling but increased the duration of the procedure (64). Similarly, an RCT comparing TA-guided transfer to TV uterine length measurement, immediately followed by an un- guided, cleaved embryo placement based on the calculated distance, showed no difference in pregnancy rates. However, in this study the TV approach had less moderate to severe discomfort largely attributable to lack of bladder filling (65).
Summary statements:
There is good evidence based on 10 RCTs to recommend TA ultrasound guidance during embryo transfer to improve clinical pregnancy rate and live-birth rate. (Grade A)
While selected ultrasound guidance for an anticipated difficult embryo transfer may be an alternative to routine ultrasound guidance, there is insufficient evidence to recommend for or against this practice. (Grade C)
Does Removing Mucus from the Endocervical Canal Improve Pregnancy and Live-birth Rates?
Some studies have indicated that cervical mucus interferes with embryo transfer by blocking the passage of embryos through the tip of the catheter, pulling embryos back from the site of expulsion, or contaminating the intrauterine envi- ronment with cervical flora. However, it has been suggested that removing cervical mucus might stimulate uterine contractility or cervical bleeding, with a possible negative impact on pregnancy outcomes.
One RCT (66) and a prospective cohort study (67) demon- strated that removing mucus from the endocervical canal with sterile cotton swabs or aspiration with a catheter, respec- tively, improves clinical outcomes. An additional published RCT was not comparable since the mucus was removed with
a cervical brush (68). A systematic review was unable to make a definitive conclusion on this topic, which was limited by the inclusion of an abstract that was never subsequently published and a study using the cytobrush (69). Therefore, data from the only well-designed RCT (N1⁄4530) and a pro- spective, controlled cohort study (N1⁄4286) were used for the recommendation (66, 67). The RCT showed improved clinical pregnancy rate (39.2% study vs 22.6% controls, P<.001) and live-birth rate (33.6% study vs 17.4% controls, P< .001) with the removal of cervical mucus (66). The clinical pregnancy rate was significantly higher in the group that had mucus aspiration compared with the group with no aspiration (P1⁄4 .003; OR 1⁄4 2.18, 95% CI 1⁄4 1.32–3.58) in the cohort study (67).
Summary statement:
ThereisfairevidencebasedononeRCTandoneprospec- tive cohort study that there is a benefit to removing cer- vical mucus at the time of embryo transfer to improve clinical pregnancy and live-birth rates. (Grade B)
Does the Type of Catheter Used for Embryo Transfer Affect Pregnancy and Live-birth Rates?
While the literature is fraught with ambiguity, there exist a number of controlled trials that provide insight into the role that the transfer catheter plays in IVF outcomes. The data as- sessing the influence of embryo transfer catheter type and IVF outcomes span almost three decades. Varying definitions of soft and firm (also called hard) catheters complicate the anal- ysis. For this analysis, any embryo transfer catheter with a soft inner catheter was classified as soft; the remainder were classified as hard catheters. In some cases, the catheters were reclassified.
Two RCTs were designed to determine if different firm catheters affected IVF outcomes (70, 71). In both trials, the Tight Difficult Transfer (TDT) catheter (Prodimed) appeared inferior. Of firm catheters studied, Tomcat (Meditech; Sherwood Medical) and FrydmanÒ (Eurosurgical; Prodimed) catheters seemed to confer a higher pregnancy rate than the Tefcat (Cook) or TDT (Meditech; Prodimed) (52, 70–73). However, data on firm catheters are mostly from the year 2000 or earlier and therefore are mainly of historical significance. Firm catheters are no longer used as a first choice for today's embryo transfer. The use of firm catheters has been supplanted by soft transfer catheters.
Two RCTs and two cohort studies favor soft over firm catheters as a means of improving IVF pregnancy rates (40, 74–76). In order to obtain pooled estimates from the two well-designed RCTs comparing soft vs firm catheters as currently defined, a meta-analysis was performed by the ASRM Practice Committee using a random-effects model. This analysis showed that pregnancy rates were higher using soft catheters for embryo transfer compared with firm cathe- ters (RR 1.36, 95% CI 1.16–1.59) (74, 75) (Fig. 3). No controlled trial favors firm over soft catheters (77).
A cohort study assessing the influence of catheter type on difficult embryo transfers failed to find benefit in using a soft catheter (78). In total, the data do not support benefit of using a firm catheter for routine use. In a trial in which patients were
Page 56 of 69
VOL. 107 NO. 4 / APRIL 2017 887
Fertility and Sterility®
PRECONGRESS COURSE 14 I BARCELONA, SPAIN – 1 JULY 2018 63