New results from an ongoing study, which previously suggested that 'flushing' the fallopian tubes with poppyseed oil might increase the chances of conception and reduce the need for IVF, indicate that this procedure continues to improve the chances of conception three years after it has been carried out.
Two presentations at the European Society of Human Reproduction and Embryology (ESHRE) annual conference in Barcelona, Spain followed up the original H2Oil study in the New England Journal of Medicine (see BioNews 901).
The original study in 1119 women examined the effects of a century-old diagnostic method called hysterosalpingography, which uses an oil- or a water-based contrast medium in the fallopian tubes to help reveal potential fertility problems. It showed that 11 percent more women in the group randomised to receive oil were pregnant within six months, compared with those whose tubes were flushed with the water solution.
Now the same research team is reporting its three-year follow-up results. Dr Joukje van Rijswijk of the VU Medical Centre in Amsterdam told the ESHRE conference that the chances of having an ongoing pregnancy within three years was higher in women who had received the oil-based rather than the water-based contrast. Receiving the oil also increased the chance of conceiving naturally or following intrauterine insemination within three years.
The oil-based procedure also reduced the median time to ongoing pregnancy: this was 10.3 months in the oil group, compared with 15.3 months in the group which received the water-based solution.
The second presentation focused on subsequent pregnancies in the study cohort. Dr Nienke van Welie, also at the VU Medical Centre, said that the initial result had 'raised the questions – is the effect still applicable to a second child, does it increase the chance of a second child?'.
A slightly higher proportion of women in the oil group (26 percent) than women in the water group (23 percent) had a second pregnancy, but this difference was not considered statistically significant.
'Though not statistically significant, better rates were found after using the oil-based contrast, with more second ongoing pregnancies and more natural conceptions' Dr van Welie added.
Professor Sjoerd Repping, an embryologist at the AMC Centre for Reproductive Medicine in Amsterdam, noted that the study did not rule out the possibility that the different results in the oil group and the water group were due to detrimental effects of the water-based solution, rather than positive effects of the oil-based solution. Dr van Welie agreed that the current study did not rule out this possibility.
Speaking to BioNews, Professor Repping said: 'We don't know what happens. It could be that there is a positive effect early on but I'm not really convinced that it is not a negative effect. The ideal trial would be to compare oil with nothing.'