OBJECTIVETo study the relationship between sperm morphology and the outcomes of in vitro fertilization-embryo transfer (IVF-ET) before and after swim-up treatment of sperm on the day of oocyte retrieval.

METHODSThis study included 94 couples to be treated by IVF-ET for tubal factor infertility. Sperm samples were collected on the day of oocyte retrieval and sperm morphology evaluated according to the Kruger criteria before and after swim-up treatment. Based on the results of morphological evaluation, the sperm samples were divided into groups A1 (morphologically normal sperm > or = 10% after swim-up treatment), A2 (morphologically normal sperm < 10% after swim-up treatment), B1 (morphologically normal sperm > or = 10% before swim-up treatment) and B2 (morphologically normal sperm < 10% before swim-up treatment). The outcomes of IVF-ET treatment were compared between groups A1 and A2 as well as between B1 and B2.

RESULTSAfter swim-up treatment, the rates of fertilization, cleavage, good quality embryo, clinical pregnancy and embryo implantation of group A1 were (72.72 +/- 3.35)%, (95.64 +/- 2.04)%, (24.39 +/- 4.57)%, 50.00% and 23.87%, respectively, while those of group A2 were (70.27 +/- 8.82)%, (94.82 +/- 4.94)%, (13.45 +/- 7.39)%, 9.52% and 6.25%, respectively, the latter three indexes remarkably higher in A1 than in A2 (P < 0.05), but the differences in the former two not statistically significant (P > 0.05). Before swim-up treatment, the above five indexes were (72.90 +/- 4.23)%, (95.20 +/- 2.61)%, (23.35 +/- 5.19)%, 39.58% and 18.35% in group B1, as compared with (71.33 +/- 5.10)%, (95.71 +/- 2.88)%, (20.18 +/- 6.15)%, 41.86% and 21.28% in group B2, with no statistically significant differences between the two groups (P > 0.05).

CONCLUSIONThe percentage of morphologically normal sperm after swim-up treatment on the day of oocyte retrieval may be a valuable predictor of the outcomes of IVF-ET.