Intrauterine insemination, what do we really know? A critical appraisal of the literature
cervical factor, effectiveness/intrauterine insemination, male subfertility,
subfertility, unexplained sub -
fertility
Abstract
Intrauterine insemination (IUI) is the first line treatment in couples
with unexplained subfertility, cervical factor subfertility and male subfertility.
To appraise the effectiveness of IUI for these three indications, we performed
a systematic review and a comprehensive series of meta-analyses. We included
Cochrane reviews and searched the literature for additional studies. Outcomes
were live birth, ongoing pregnancy, clinical pregnancy and multiple pregnancy
.
We were able to include 14 studies reporting on IUI for unexplained subfertility,
two studies reporting on IUI for cervical factor subfertility and nine
studies reporting on IUI in male subfertility.
In couples with unexplained subfertility, IUI without controlled ovarian
hyperstimulation (COH) was associated with higher ongoing pregnancy rates
than expectant management (relative risk (RR) 1.3, [95% CI 0.84 to 1.9]),
whereas IUI with COH was more effective than IUI without COH (RR 1.8, [95%
CI 1.2 to 2.7]). However, in couples with relatively good prospects for
spontaneous pregnancy, there was no benefit from IUI with COH over expectant
management . In couples with a cervical factor, IUI without COH was
associated with higher pregnancy rates compared to expectant management
(RR 1.6, [95% CI 0.87 to 3.1]), but addition of COH did not further improve
the pregnancy rates (RR 1.0, [95% CI 0.59 to 1.8]). In couples with male
subfertility, IUI was more effective than expectant management, although
the limited power of the included studies hampers strong conclusions. In
these couples, addition of COH also had no extra benefit (RR 0.92, [95%
CI 0.46 to 1.8]). Studies comparing IUI and IVF were rare, limiting assess
ment of the strategy of IVF as first line treatment.
Despite the fact that IUI is one of the most frequently used treatments
in reproductive medicine, our review shows that the number of studies assessing
it’s effectiveness is limited and that most of these studies had small
sample sizes. This results in imprecise effect estimates, as demonstrated
by the non significant effects and large confidence intervals. Also, many
studies did not adhere to present quality standards for design, conduct
and report of clinical trials. Therefore, there is an urgent need for more
RCTs in which IUI is compared to expectant management or IVF.