Seang Lin Tan

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In order to achieve a clinical pregnancy rate higher than that achieved following initial adoption of in-vitro fertilization embryo transfers, more than one embryo is transferred. This has led to a substantial increase in unwanted multiple pregnancy rates with IVF as compared with natural conception. What is therefore required is a simple, clinically useful(More)
OBJECTIVE To compare the obstetric outcome of in vitro fertilization pregnancies with normally conceived pregnancies. STUDY DESIGN The obstetric outcome of in vitro fertilization pregnancies achieved in 763 British residents at two in vitro fertilization clinics resulting in the births of 961 babies were compared by means of the relative risk statistic(More)
BACKGROUND A large percentage of in-vitro generated cleavage stage human embryos are chromosomally mosaic, consisting of both normal (diploid) and abnormal (non-diploid) cells. The present study characterized mosaicism at each stage of cleavage division and examined its effect on preimplantation development in vitro. METHODS A total of 216 normally(More)
The present study examined whether the rates of oocyte maturation, fertilization and development, as well as pregnancy rate could be improved by human chorionic gonadotrophin (HCG) priming 36 h before immature oocyte retrieval in patients with polycystic ovarian syndrome (PCOS). Immature oocyte retrieval was performed on day 10-14 of the cycles and patients(More)
A total of 96 women undergoing in vitro fertilization (IVF) treatment were studied on the day of human chorionic gonadotropin (hCG) administration by transvaginal ultrasonography with color and pulsed Doppler ultrasound. We assessed endometrial thickness, endometrial morphology, presence or absence of subendometrial or intraendometrial color flow,(More)
OBJECTIVE To relate changes in serum and follicular fluid vascular endothelial growth factor (VEGF) concentrations to Doppler blood flow velocities within ovarian and uterine blood vessels during IVF cycles and to assess their relation to ovarian hyperstimulation syndrome (OHSS) and polycystic ovaries (PCO)/polycystic ovary syndrome (PCOS). DESIGN(More)
OBJECTIVE To investigate differences in immature oocyte maturation, fertilization, and pregnancy rates among women with unstimulated normal ovaries, polycystic ovaries (PCOs), or PCOS. DESIGN Prospective observational study. SETTING University fertility clinic. PATIENT(S) One hundred forty-four women undergoing 180 in vitro oocyte maturation treatment(More)
To assess the risk of miscarriage after in-vitro fertilization (IVF) with respect to age, cause of infertility, ovarian morphology and treatment regimen, a retrospective analysis was performed of the first 1060 pregnancies conceived between June 1984 and July 1990 as a result of 7623 IVF cycles. Superovulation induction was achieved with human menopausal(More)
OBJECTIVE To compare obstetric outcome and congenital abnormalities in pregnancies conceived after in vitro maturation (IVM), in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI) with those in spontaneously conceived controls. METHODS Data were collected from the McGill Obstetrics and Neonatal Database (MOND). All children were(More)
OBJECTIVE To assess whether a measure of uterine blood flow impedance (the pulsatility index, PI) as determined by transvaginal ultrasonography with color blood flow imaging, may be used to assess endometrial receptivity immediately before the time of embryo transfer (ET) after assisted conception. DESIGN A prospective study of infertile women who had(More)