BACKGROUND Focus on the hatching process has so far been in the field of fresh embryos. Cryopreserved-thawed embryos have a lower rate of pregnancy than fresh embryos, which might be due to hardening of the zona pellucida. METHODS During a 2 year period, a prospective randomized study enrolling 253 cryopreserved-thawed cycles was performed on day 2 embryos. Pseudorandomization to assisted hat...

The aim of the study was to compare the single pregnancy and neonate outcome after fresh and frozen-thawed embryo transfer in the in vitro fertilization programme (IVF). The study focused on clinical and laboratory factors affecting the abnormal placentation, especially placenta praevia, in patients conceiving in the IVF programme. The results confirm that neonates born after frozen-thawed embr...

OBJECTIVE To evaluate the maturation and post-thaw survival rates of immature oocytes to determine whether in vitro maturation (IVM) should be attempted prior to or after cryopreservation. DESIGN Nonrandomized observational study. SETTING Private academic and clinical reproductive center. PATIENT(S) Patients (n = 71) who donated immature unusable oocytes after vaginal oocyte retrieval (VO...

BACKGROUND Although routinely used in assisted reproductive technology, human sperm cryopreservation is not an entirely successful procedure. This study determined the effect of nerve growth factor (NGF) supplementation of cryopreservation medium on post-thaw viability, motility, intracellular nitric oxide (NO) concentration, and DNA fragmentation of human spermatozoa in asthenozoospermic men. ...

This study was prompted by the observation that fresh platelet suspensions--prepared by gel filtration or albumin density gradient centrifugation--possessed only minimal factor V activity, whereas frozen-and-thawed platelet suspensions possessed striking factor V activity. Results of experiments with fresh suspensions suggested that unaltered platelets did not bind plasma factor V. The factor V...

The value of the ability to cryopreserve and store germplasm has long been recognized for indefinite preservation of genetic material, especially for at-risk populations. In contrast to domestic livestock species, cryogenic storage of poultry semen is not reliable enough for germplasm preservation. The relatively low fertilizing ability of frozen/thawed poultry sperm most likely results from ph...

OBJECTIVE To investigate the effect of slow cryopreservation on the morphology and function of primate primordial follicles within ovarian tissue slices. DESIGN Fresh monkey ovarian tissue was frozen by slow cryopreservation and thawed for analysis of morphologic and functional parameters. SETTING University-affiliated laboratory. ANIMALS Rhesus monkey ovarian tissue. INTERVENTION(S) No...

Objective. To optimise the use of freeze/thaw testicular immotile spermatozoa from nonobstructive azoospermia patients and to analyse the outcome of intracytoplasmic sperm injection (ICSI) of such spermatozoa. Methods. Testicular specimens were retrieved and cryopreserved from forty patients with nonobstructive azoospermia and underwent one cycle with thawed spermatozoa (Group I) that led to pr...

OBJECTIVE This study aims to evaluate the effectiveness of GnRH agonist in comparison with hCG for triggering final oocyte maturation in endometrial preparation of letrozole stimulation protocols for frozen-thawed embryo transfer. METHODS The frozen-thawed embryo transfer cycles (FET) that use the letrozole stimulation protocols for endometrial preparation were divided into two groups accordi...

The present study was undertaken to examine the viability, motility and morphology of spermatozoa that were frozen-thawed at different temperature followed by the storage at 4oC until 10 hours under the condition of tropical area. The frozen semen derived from a Holstein-Friesian bull with the egg-yolkbase extender was thawed at 23oC or 37oC for 30 seconds or 15 seconds, respectively, and kept ...