Initial IVF-ET Experience with Assisted Hatching Performed 3 Days After Retrieval Followed by Day 5 Embryo Transfer

Objective: To report our initial IVF-ET experience combining assisted hatching performed 3 days after oocyte retrieval with day 5 embryo transfer (ET).

Design: Retrospective review of 110 consecutive IVF cycles not involving donor oocytes, including 16 cycles that involved assisted hatching performed 3 days after oocyte retrieval in combination with day 5 ET.

Setting: Academic teaching hospital IVF center.

Patient(s): Eighty-six consecutive IVF patients undergoing ET.

Intervention(s): Assisted hatching using acid Tyrode's solution performed 3 days after oocyte retrieval in selected cases in combination with day 3 or 5 ETs.

Main Outcome Measure(s): Clinical pregnancy rate per ET.

Result(s): Of the 16 women undergoing day 5 ET following day 3 assisted hatching, 14 had a clinical pregnancy. These included 11 ongoing/delivered singletons and 2 ongoing/delivered twin pregnancies, neither of which was monochorionic. These clinical and ongoing/delivered pregnancy rates compared very favorably with those of 54% and 46%, respectively, for the 35 patients undergoing day 5 ETs without assisted hatching, even though the latter group appeared to be better IVF candidates based on the prognostic factors commonly used to predict success.

Conclusion(s): Our experience suggests that day 3 assisted hatching followed by day 5 ET may be a useful combination in selected patients. Although not seen in our small series, an increased risk of monochorionic pregnancies remains a theoretical concern when such a combination is used, since both assisted hatching and blastocyst transfers have been independently linked to an increased risk in some reports.