Late hCG administration yields more good quality embryos and favors the overall IVF outcome

摘要

Context: Optimal timing of hCG administration is a crucial step for successful IVF. Currently used standard hCG administration timing is not always practically possible due to weekends break or other reasons. Sometimes hCG needs to be administrated earlier or later than standard timing. Aim: To find out whether earlier or later hCG administration gives better IVF outcome. Setting and Design: A retrospective study on patients who underwent conventional IVF treatment. Methods and Material: Based on hCG timing, the patients were divided into three groups: the early hCG group where the hCG was given when less than three follicles ≥ 17 mm;the standard hCG group where the hCG was given when three or more follicles ≥ 17 mm;and the late hCG group where the hCG was given 1 to 3 days after the standard timing. The number of retrieved mature oocytes, the fertilization rate, the number of good quality embryos, the pregnancy rate and the live birth rate were compared among three groups. Statistical Analysis: x2 test, fisher exact test and Student t-test were used. Results: in total, 289 patients, 305 IVF cycles and 2784 oocytes were analyzed. The late hCG group has significantly larger number of MII oocytes, fertilized oocytes and good quality embryos per IVF cycle, when compared with the early hCG group. The fertilization rate, the pregnancy rate and the live birth rate per IVF cycle were similar among the three groups. Conclusion: Although the delayed administration of hCG did not favor IVF outcome per IVF cycle, the cumulative pregnancy rate is likely to be improved with consideration of higher yield of good quality embryos.