The attempt to use old medications for a new application is
not an uncommon occurrence in the medical world, as researching currently used
medications often circumvents many of the challenges clinical trials of new
molecules present. However, we were rather surprised to hear that there are
overseas fertility clinics that suggest the use of sildenafil may be beneficial
for some women undergoing IVF treatment.
The reasoning behind this comes from a handful of old
studies considering the potential link between sildenafil and the thickness of
a woman’s endometrium. The researchers of those studies argue that sildenafil,
which is the active ingredient in medications such as Viagra, could improve
uterine blood flow and combined with ovarian hyper-stimulation contribute to
production of endometrial lining.
Although one line of reasoning argues that the thickness of
the endometrium plays a key role in the fertilisation process, the studies to
date do not provide sufficient support for advocating the use of sildenafil for
these purposes.
First, it is worth noting that of all the studies published
only one had a somewhat suitable sample size of 105 women, whereas the other
studies included sizes from 4-30 participants. This is not surprising given
that the recruitment of participants may be particularly challenging in this
type of research. Nevertheless, we agree with the researchers conclusions that
it is not possible to make reliable conclusions based on those limited samples
and that more research needs to be done. Secondly, although the rates of
success have varied between the studies, no study has provided impressive or
significant results. Perhaps this was due to the fact that the participants
exhibited a range of problems that were impossible to exclude but caused
trouble in the data analysis. Thirdly, the nature of all the studies conducted
was correlational, thus making it impossible to establish causality. Lastly, it
is worth noting that all the studies within this area used sildenafil as a
vaginal suppository and not as an oral medication.
Since the publication of these studies, which
occurred between 2000 and 2006, the scientific community has remained quiet
regarding this topic. Given the long, complex and sensitive process of
conception to birth it is clear that no simple answer can help women with their
fertility. As such, more studies need to be conducted in a range of areas, but
for now it is safe to state that the evidence for using sildenafil to improve
IVF treatment is insufficient to convince us.