Is the timing of implantation affected by zona pellucida micromanipulation?

Our purpose was to examine the timing of implantation and early embryo development following uterine transfer of oocytes/embryos previously subjected to zona pellucida micromanipulation. A total of 68 singleton pregnancies resulting from IVF and embryo transfer with/without micromanipulation. Patients were divided into four groups according to the type of micromanipulation technique: assisted hatching, embryo biopsy, intracytoplasmic sperm injection, and no micromanipulation (control group). Serial serum beta-hCG levels were measured between 10 and 25 days after fertilization and log-transformed. Linear regression analyses were performed and extrapolated to hCG = 10 mIU/ml (hCG10) to estimate detectable implantation. The slopes of the regression lines were used to estimate the rising speed of hCG, an indirect sign of embryo development. There were no significant differences among groups with respect to hCG10, the slopes or intercepts of the regression lines. Various oocyte/embryo microsurgical procedures used in ART involving zona pellucida manipulation do not appear to affect the timing of implantation or early embryo development.