Background: In spite of the great deal of research in assisted reproductive techniques, more than 80% of transferred embryos by IVF/ICSI methods fail to be implanted. The causes for repeated implantation failures (RIF) may be reduced endometrial receptivity or other various uterine pathologies, such as thin endometrium, altered expression of adhesive molecules or immunological factors; whereas ...

The hatching of a blastocyst where the blastocyst portions on the inside and the outside of the zona pellucida feature a figure-of-eight shape is termed "8"-shaped hatching; this type of hatching has been reported to affect the proper presentation of the inner cell mass (ICM) in both human and mouse embryos. Here, our aim was to investigate the factors that affect ICM presentation during "8"-sh...

Chicks from 0 to 61 days post-hatching were gently folded into the hatching position and placed in artificial glass eggs. Within 0 to 2 min they began to produce a behavior that qualitatively resembled normal hatching. Furthermore, quantitative analysis of electromyographic records showed that under these conditions the intralimb and interlimb leg motor output patterns produced during each hatc...

OBJECTIVE To verify whether advantages can derive from the implementation of preimplantation genetic diagnosis for aneuploidy in patients with a poor prognosis of full-term pregnancy, compared with conventional treatment procedures. DESIGN A randomized, controlled study. SETTING Reproductive Medicine Unit of the Società Italiana Studi Medicina della Riproduzione, Bologna, Italy. PATIENT(S...

Objective This study was conducted to investigate the efficacy of laser-assisted hatching (LAH) and various vitrification times for embryonic development and blastocyst cell numbers. Methods First, 2-cell and 8-cell embryos were collected by flushing out the oviducts. In the control groups, they were vitrified for 8 or 10 minutes without LAH. The LAH groups underwent quarter laser zona thinni...

Many species alter the timing of hatching in response to egg or larval predators, pathogens, or physical risks. This plasticity depends on separation between the onset of hatching competence and physiological limits to embryonic development. I present a framework based on heterokairy to categorize developmental mechanisms and identify traits contributing to and limiting hatching plasticity, the...

Embryos attached to the female crab Sesarma haematocheir hatch synchronously within 1 h. Hatching is also synchronized near the time of the expected nocturnal high tide. These events are governed by a single circatidal clock (or pacemaker) in the female crab. The present study examined the role of the optic peduncle of the eyestalk on hatching and hatching synchrony. Surgery was performed eithe...

Increased variance in the reproductive success of males relative to females favors mothers that optimally allocate sons and daughters to maximize their fitness return. In altricial songbirds, one influence on the fitness prospects of offspring arises through the order in which nestlings hatch from their eggs, which affects individual mass and size before nest leaving. In house wrens (Troglodyte...