Wednesday 2 May 2007
Fertility research round-up
Issue 09: 1 May 2007
Source: Fertility and Sterility 2007;87(suppl 2):S1-26
The 2007 annual meeting of the Pacific Coast Reproductive Society took place in Rancho Mirage, in California, USA, from 18-22 April. The abstracts of the papers and posters presented at the meeting are available in a supplement to the journal Fertility and Sterility, and below are the key findings of a small selection:
Effects of Asian ethnicity on presentation and outcomes
Asian ethnicity is associated with “a longer duration of infertility and possibly lower pregnancy rates” after intra-uterine insemination, according to a study by Lamb et al (San Francisco, USA). The researchers performed a retrospective study of 439 patients who underwent 1,563 cycles between December 2002 and December 2004. A total of 256 of the patients (58.3 percent) were Caucasian and 130 (29.6 percent) were Asian. The baseline demographic characteristics of the two groups were the same except for duration of infertility, which was significantly longer in Asian patients; for example, just over 10 percent of Asian patients had a history of infertility longer than 5 years, compared with 1.3 percent of Caucasians. The researchers also found that the pregnancy rate after four cycles was lower in the Asian patients (18.5 percent) than in the Caucasian patients (25.8 percent), although the difference was not statistically significant. They comment: “Determining if the duration of infertility prior to initial presentation contributes to the difference in pregnancy rates may allow an intervention to improve Asian treatment outcomes.” (pages S16)
Rapid embryo growth in vitro and in utero?
Shapiro et al (Las Vegas, USA) conducted a study to determine whether rapid embryo growth in vitro corresponds with initial rapid growth in utero. They studied 26 cycles of singleton pregnancies resulting from day 5 (10 cycles) and day 6 (16 cycles) blastocyst transfers, measuring serum levels of human chorionic gonadotropin (hCG) up to 13 days after transfer. The day 5 blastocyst transfers were found to yield a significantly more rapid rise in serum hCG levels than day 6 blastocyst transfers. For day 5 transfers, median serum hCG levels rose from 57.0 mIU/mL on day 6 to 1501.6 on day 13 post-transfer; for day 6 transfers, median levels rose from 56.9 on day 6 to 914.2 on day 13. The researchers conclude: “This suggests that embryos that grow more rapidly prior to transfer continue to develop more rapidly for several days after transfer.” (page S16)
A trial of “embryo glue”
Dietterich et al (Camden, USA) investigated whether the use of an “embryo glue” – a substance with the active ingredient hyaluronan, intended to help embryos attach to the endometrial wall – could improve pregnancy rates following embryo transfer in women who had previously failed to conceive despite at least three embryo transfers. The researchers investigated the use of glue in 28 fresh embryo transfers and in 13 frozen embryo transfers, and found that for both types of transfer the clinical and delivered pregnancy rates were not significantly higher when the glue was used than in matched women in whom glue was not used. (page S14)
Causes of recurrent pregnancy loss
Recurrent pregnancy loss in women over 35 is more often due to age-related aneuploidy than to underlying thrombophilias or abnormalities of the uterine cavity, a study by Lathi (Stanford, USA) has demonstrated. The retrospective review of medical records from 1999-2006 identified 38 women with a history of three or more miscarriages who were over 35 years old at the time of the third miscarriage. Embryonic genetic evaluation of 42 miscarriages in these women showed that the prevalence of chromosomal abnormalities was 74 percent. This was not significantly higher than the 71 percent incidence of chromosomal abnormalities seen in a comparison group of older women with sporadic miscarriages (defined as two losses). Of the 38 cases, 34 had thrombophilia evaluations of which 30 were normal; the remaining four had previously been diagnosed with antiphospholipid antibody syndrome. In addition, 35 out of the 37 cases who had uterine cavity evaluations had a normal result. The researchers say the study findings indicate that “aneuploidy is the primary reason for recurrent pregnancy loss in women over 35.” (page S8)
For more information about the annual meeting, and about the society, visit
www.pcrsonline.org.
http://www.orgyn.com/en/webzine/2007...92043204513889
Fertility research round-up 
