The effect of long zona dissection using ICSI pipettes for mechanical assisted hatching in vitrified-thawed blastocyst transfers

Abstract

To investigate the effect of long zona dissection (LZD) compared with partial zona dissection (PZD) using ICSI pipettes for mechanical assisted hatching (AH) in vitrified-thawed blastocyst transfers. Prospective study. University IVF clinic. A total of 120 women ≦ 38years old undergone vitrified-thawed blastocyst transfers with LZD or PZD. The culture of all pronucleate embryos to the blastocyst stage and the selection of blastocysts ≧ grade 3BB (Gardner and Schoolcraft score), followed by vitrified-thawed blastocyst transfers with LZD (n = 60) or with PZD (n = 60) Complete hatching rates, implantation rates, pregnancy rates. At 5h after thawing, complete hatching rates of blastocysts were significantly higher in LZD group compared with PZD group, 52.4% vs. 31.8% (P = 0.001). Implantation and clinical pregnancy rates were significantly higher in LZD group compared with PZD group, 40.9% vs. 25.7% and 63.0% vs. 40.0%, respectively (P = 0.010, P = 0.011). LZD using ICSI pipettes for mechanical AH improves significantly complete hatching, implantation and pregnancy rates in vitrified-thawed blastocyst transfers.