Best site for embryo transfer: the upper or lower half of endometrial cavity?

Abstract

The implantation or pregnancy rates were similar whether the embryos were deposited in the upper or lower half of the endometrial cavity.

Impact of embryo replacement depth on in vitro fertilization and embryo transfer outcomes

“…Among these factors are ultrasound guidance, transfer catheter type, catheter-loading technique, uterine cavity fluid, blood or mucus effects, retained embryos, mock transfer, myometrial contractions, and facility of the procedure. In addition to these variables, the site of embryo placement in the uterine cavity has recently been postulated to influence embryo implantation rates (9)(10)(11)(12)(13). In their study, Frankfurter et al (9) analyzed their videotapes of embryo transfers in pregnant and nonpregnant cycles.…”

“…Although the discussion regarding the best site within the endometrial cavity for embryo transfer preserves its actuality, a study by Franco et al (13) claimed that this question was of no importance as the site of embryo transfer did not influence implantation rates.…”

“…The common end-result achieved by these studies was that embryo transfer at or within 10 mm of the fundal endometrial surface was associated with a lower pregnancy rate (PR) compared with embryo transfer >10 mm below the fundal endometrial surface (10)(11)(12). But, in their study, Franco et al (13) found that the implantation rates or PRs were similar whether the embryos were deposited in the upper or lower half of the endometrial cavity. Finally, in a recent meta-analysis by Abou-Setta (14), all live birth rate, ongoing PR, and clinical PR were significantly higher for the approximately 20-mm versus approximately 10-mm distance from the uterine fundus.…”

“…Along with these factors on treatment success, the site of embryo transfer has also been debated by several investigators but lacks a consensus (9)(10)(11)(12)(13). Several studies demonstrated a significant effect of embryo transfer depth on IVF and embryo transfer outcomes (9)(10)(11)(12).…”

Air bubble migration is a random event post embryo transfer

“…The presence of air bubbles next to embryos in the uterus does not cause embryo expulsion, studied during mock transfers using methylene blue marker [8]. A wide window of implantation with similar pregnancy rates was observed when the uterus was divided into upper and lower half cavities [9]. Additional support of this practice came from studies that demonstrated that 80% of embryo implantations occurred in the original area of transfer [10].…”