Is fine morphology of the human sperm nuclei affected by in vitro incubation at 37 degrees C?

OBJECTIVE: Incubation of ejaculated spermatozoa at 37 degrees C is recommended for IVF-intracytoplasmic sperm injection. Preselection of sperm cells with morphologically normal nuclei before microinjection, adapted in our laboratory, is usually a time-consuming procedure. Therefore, we aimed to verify whether incubation at 37 degrees C could affect the morphologic integrity of sperm nuclei. DESIGN: Time-kinetics studies testing fine morphology of the sperm nuclei upon prolonged in vitro incubation. SETTING: Male Fertility Laboratory at Bar-Ilan University, Ramat Gan, Israel. PATIENT(S): Forty-two males selected at random, who were referred for sperm preselection before ICSI. MAIN OUTCOME MEASURE(S): Morphologic integrity of the sperm nuclei, obtained by motile sperm organelle morphology examination. RESULT(S): After 2 hours of incubation at 37 degrees C a significant decrease occurred in the morphologic integrity of the sperm nuclei, compared with the initial state (4.7% +/- 2.8% vs. 6.8% +/- 3.5%, t = 3.2, Por=2 hours) sperm manipulations for assisted reproduction therapy should be performed at 21 degrees C rather than 37 degrees C.

Does the presence of nuclear vacuoles in human sperm selected for ICSI affect pregnancy outcome?

BACKGROUND: To verify whether or not microinjection of sperm with a normal nuclear shape but large vacuoles affects IVF-ICSI pregnancy outcome. METHODS: A comparative study testing IVF outcome parameters of IVF-ICSI, based on morphological selection of spermatozoa with normal nuclei against those based on microinjection of sperm with a normal nuclear shape but large vacuoles. An experimental group, including 28 IVF-ICSI cycles, where only embryos obtained from microinjection of spermatozoa with a normal nuclear shape but large vacuoles were transferred, was matched with a control group, including 28 IVF-ICSI cycles, where only embryos obtained from microinjection of spermatozoa with a strictly defined morphologically normal nuclear shape and content were transferred. The main outcome was IVF-ICSI pregnancy rate. RESULTS: The experimental group exhibited a significantly lower pregnancy rate per cycle and significantly higher abortion rate per pregnancy compared to the control group (18 versus 50%, and 80 versus 7%, respectively, P=0.01). CONCLUSION: Microinjection of vacuolated sperm appears to reduce the pregnancy rate and appears to be associated with early abortion.