RESUMEN
BACKGROUND: Degeneration of oocytes occurs even when maximum care is exercised during ICSI, especially when the oolemma is very fragile and/or the zona pellucida is resistant. In order to be able to minimize the risk of degeneration associated with microinjection this study applied a new method: a microhole on the zona pellucida of the oocyte was drilled by laser beam just prior to ICSI to permit the penetration of the microneedle without any trauma. METHODS: A total of 32 patients (32 cycles) who had one or more previously failed ICSI cycles with a high degeneration rate of oocytes (>20%) were included in the study. Oocytes of the same patients were randomly divided into the study group [laser-assisted ICSI (LA-ICSI)] and the control group [conventional ICSI (C-ICSI)]. The outcomes of the cycles were compared and analysed. RESULTS: After LA-ICSI compared with C-ICSI, survival rates of oocytes were 99.6 and 84% (P < 0.0001), fertilization rates were 76.6 and 68.6% (not significant) and embryo development rates ( vertical line 6 cells on day 3) were 76.5 and 57.3% (P = 0.0024) respectively. CONCLUSIONS: Creating a microhole on the zona pellucida of the oocyte by laser beam prior to ICSI provides a less traumatic penetration of the injection needle into the ooplasm and results in lower degeneration and higher embryo development rates than C-ICSI in patients with fragile oocytes.
Asunto(s)
Embrión de Mamíferos/fisiología , Rayos Láser , Oocitos/fisiología , Inyecciones de Esperma Intracitoplasmáticas/métodos , Adulto , Transferencia de Embrión , Desarrollo Embrionario y Fetal , Femenino , Hormona Folículo Estimulante/administración & dosificación , Humanos , Leuprolida/administración & dosificación , Masculino , Microinyecciones/métodos , Oocitos/ultraestructura , Embarazo , Recolección de Tejidos y Órganos , Resultado del Tratamiento , Zona Pelúcida/ultraestructuraRESUMEN
The incidence of monozygotic twinning (MZT) is higher in pregnancies conceived after assisted reproduction than after natural conception. Alterations, produced by ovarian stimulation, in-vitro culture conditions and specifically alterations of zona pellucida are mentioned as possible causes of this phenomenon. A retrospective review was performed of the incidence of MZT in pregnancies generated in our centre during the period of January 1996 to December 1999. This variable was compared in 129 gestations that resulted from blastocyst transfer (occurring from September 1998 to August 1999) with 814 pregnancies produced by transfers of 4- to 8-cell embryos. Follicular development was induced with human menopausal gonadotrophin and urinary FSH during 1996 and 1997 and with recombinant FSH during 1998 and 1999. Blastocysts were cultured in sequential media using S1 or G1 up to 72 h and S2 or G2 to day 5. Five of the 129 pregnancies generated by blastocyst transfers were complicated by MZT gestation (3.9%). In comparison, only six of 814 pregnancies occurred from 4- to 8-cell transfers (0.7%), a difference that is statistically significant (P< 0.001 with Yates correction). The results confirm an increase of MZT in pregnancies from intracytoplasmic sperm injection as compared to the natural incidence. Moreover, the frequency of MZT was significantly higher when transfers were performed at the blastocyst stage, suggesting that extended in-vitro culture of embryos may be associated with alterations of the zona pellucida and the hatching process.
Asunto(s)
Transferencia de Embrión/efectos adversos , Transferencia de Embrión/métodos , Inyecciones de Esperma Intracitoplasmáticas , Gemelos Monocigóticos , Adulto , Blastocisto , Femenino , Humanos , Técnicas In Vitro , Recién Nacido , Masculino , Embarazo , Resultado del Embarazo , Embarazo Múltiple , Estudios RetrospectivosRESUMEN
The two main causes of complete or nearly complete asthenozoospermia are necrozoospermia (presence of only non-viable spermatozoa) and the different ultrastructural abnormalities of spermatozoa. Ultrastructural alterations may affect also the function of the sperm centrosome, which can result in impaired motility. Because in human the inheritance of the centrosome is paternal and thus linked to the sperm, morphological or functional alterations of it can also be associated with fertilization abnormalities of the oocyte and cleavage irregularities of the embryo. Most of the cases of asthenozoospermia can be treated efficiently by intracytoplasmic sperm injection (ICSI) using ejaculated sperm (from repeated ejaculation) in combination with hypo-osmotic swelling test (HOST) or using testicular sperm depending on the etiology of the impairment. Replacement of abnormal centriole using donor sperm is a theoretical possibility, but at present it is not an efficient method.