April 2008

Oral presentations at the 2nd ASPIRE & PRSFS conference

Two papers were accepted as oral presentations at the 2nd ASPIRE & PRSFS (11-14th April 2008) conference, an international meeting on fertility treatment. The titles were “How embryo transfer distance influences implantation and pregnancy rates” and “The eradication of Ovarian Hyperstimulation Syndrome (OHSS)?.” The topics of the two papers centred on both improving success and decreasing risk in fertility treatment.

Medical Director Dr Cheng Li Chang's presentation on “The eradication of Ovarian Hyperstimulation Syndrome (OHSS)?” won first prize of the Serono Young Investigator's Award.

The authors of the first paper (Drs Preeja S, CM Chia and LC Cheng) studied how embryos transferred at three different distances from the uterine fundus affected implantation and pregnancy rates.

Their study showed that the position of the embryo transfer has a significant impact on implantation and pregnancy rates and the highest implantation and pregnancy rates were obtained when embryos were transferred at a distance of 2-2.99 cm from uterine fundus.

The second paper which won the Serono's Young Investigator's Award is one of the largest studies using GnRH agonist as trigger for ovulation in lieu of hCG in a GnRH antagonist ovarian hyperstimulation. OHSS remains the most serious complication affecting women undergoing IVF. This study evaluates the incidence of OHSS in high risk individuals using this protocol.

All existing protocols that use hCG to trigger final oocyte maturation are associated with a risk of OHSS.

The doctors did a preliminary analysis of Polycystic ovarian (PCO) high-responders in IVF cycles using the Antagonist protocol where a GnRH-agonist was used for triggering final oocyte maturation instead of hCG.

The successful use of protocol has been reported (Kol S et al, 2000) with no adverse effect except for poor pregnancy outcome (Kolibianakis etal, 2005). This was thought to be related to a luteal phase defect caused by the GnRH agonist. This is similar to the doctors’ experience (2 live births out of 37 transfers).

The most significant finding from the use of agonist as a trigger for ovulation is eliminating the risk of Moderate/ Severe OHSS in high risk patients and the need to cancel the cycle. Freezing all embryos would also eliminate the risk of late onset OHSS and high pregnancy rates were achieved in subsequent thaw cycles.