To assess the association of zona pellucida micromanipulation and subsequent development of monozygotic twins, cases of assisted embryo hatching (AH) and intracytoplasmic sperm injection (ICSI) were identified and related to treatment type, implantation and zygosity data. Embryology records from all patients undergoing in-vitro fertilization (IVF) at this centre from January 1995 to March 1998 ...

BACKGROUND Cryopreservation of embryos may lead to zona hardening that may compromise in vivo hatching and implantation following thawing and transfer. Assisted hatching (AH) has been advocated as a means of assisting the natural hatching process and enhancing implantation. METHODS The aim of this study was to assess in a prospective randomized manner the effect of laser-assisted hatching (LA...

BACKGROUND Human chorionic gonadotropin (HCG), one of the initial embryonic signals, is probably a major regulator of the embryo-endometrial relationship. This study aims to assess the advantage of HCG supplementation during the secretory phase of hormonally prepared cycles for the transfer of cryopreserved-thawed embryos. MATERIALS AND METHODS This study was a randomized clinical trial. Infe...

STUDY QUESTION Are there differences in estrogen and progesterone secretion in singleton pregnancies, up to Week 11, between spontaneous pregnancies, after controlled ovarian hyperstimulation and fresh embryo transfer (COH + ET) and after frozen embryo transfer in a spontaneous cycle (FET)? SUMMARY ANSWER Serum progesterone and estradiol (E2) concentrations after COH + ET were higher in early...

BACKGROUND Embryo implantation process is a complex phenomenon and depends on fetal and maternal factors interaction. Endometrial thickness is needed for successful implantation. OBJECTIVE We designed this study in order to assess adding human chorionic gonadotropin (HCG) to the conventional protocol in endometrial preparation in women with thin endometrium and a history of in vitro fertiliza...

The ultimate challenge for all in vitro fertilisation (IVF) clinics is to develop the ability to select for transfer the best single embryo first, from the patient’s cohort of embryos, thereby maximising the chance of pregnancy while the incidence of multiple pregnancies is kept to a minimum and fewer transfer cycles are required. This ambition has driven extensive research and development into...

A major cause of cycle cancellation during controlled ovarian hyperstimulation (COH) in women undergoing in vitro fertilization (IVF) is the occurrence of premature luteinizing hormone (LH) surges. Steroidal preparations can modulate the secretion of gonadotropins (Gn); however, few studies using progesterone to inhibit the premature LH surges in COH have been published. The purpose of the stud...

Case To present an extremely rare case of bilateral tubal pregnancies following a single-embryo transfer in a woman with a 4 year history of infertility prior to seeking assisted reproductive technology. Outcome A pregnancy resulted from the transfer of an embryo that had been thawed from a frozen blastocyst during a hormone replacement cycle. An ultrasound that was performed at 5 weeks and 5...

This paper provides a concise review of single embryo transfer (SET) in cycles using fresh embryos as well as in cycles using frozen-thawed embryos. Relevant studies were identified by a computerized search in PubMed for the period 1995-2004. The pregnancy rates, delivery rates and multiple pregnancy/birth rates were evaluated after fresh or frozen embryo transfer as well as cumulative delivery...

On a worldwide basis, more than 750,000 embryos are produced annually from superovulated donors and more than 450,000 embryos are produced using in vitro techniques. Superovulation and embryo collection are done as frequently as every 30 days. Cryopreservation and direct transfer of frozen-thawed embryos results in pregnancy rates near that of fresh embryos. Since the zona pellucida-intact in v...