In vitro fertilisation (IVF) may lead to more pregnancies than other options for unexplained infertility, but the evidence is not conclusive

IVF is frequently used for couples with unexplained infertility as it may be able to bypass a variety of biological problems by ensuring fertilisation outside the body. However, it is expensive, invasive and can lead to complications (including multiple births). Other options for unexplained infertility include trying naturally for a pregnancy, drugs to stimulate the ovaries ('fertility drugs') and introduction of washed sperm within the womb (insemination). The review of trials found that IVF may result in more births than other techniques for couples with unexplained infertility, but the research is not conclusive. Adverse outcomes and costs have not been adequately addressed in the trials.

Authors' conclusions: 

IVF may be more effective than IUI+SO. Due to paucity of data from RCTs the effectiveness of IVF for unexplained infertility relative to expectant management, clomiphene citrate and IUI alone remains unproven. Adverse events and the costs associated with these interventions have not been adequately assessed.

Read the full abstract...

In vitro fertilisation (IVF) is a widely accepted treatment for unexplained infertility (NICE 2004), which affects up to a third of all infertile couples. With estimated live birth rates (LBRs) per cycle varying from 33.1% in women aged under 35 years down to 12.5% in women aged between 40 and 42 years (HFEA 2011), its effectiveness has not been rigorously evaluated in comparison with other treatments. With increasing awareness of the role of expectant management, less-invasive procedures such as intrauterine insemination (IUI), and concerns about multiple pregnancies and costs associated with IVF, it is important to evaluate the effectiveness of IVF against other treatment options in couples with unexplained infertility.


To evaluate the effectiveness and safety of IVF compared to expectant management, clomiphene citrate, IUI alone and intrauterine insemination plus controlled ovarian stimulation (IUI+SO).

Search strategy: 

Cochrane Menstrual Disorders and Subfertility Group Trials Register (searched July 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, first quarter), MEDLINE (1970 to July 2011), EMBASE (1985 to July 2011) and reference lists of articles were searched. Relevant conference proceedings were handsearched. Authors were contacted.

Selection criteria: 

Randomised controlled trials (RCTs) were included. LBR per woman was the primary outcome.

Data collection and analysis: 

Two review authors independently assessed eligibility and quality of trials.

Main results: 

Six RCTs were included in the final analysis. LBR per woman was significantly higher with IVF (45.8%) than expectant management (3.7%) (odds ratio (OR) 22.00, 95% confidence interval (CI) 2.56 to 189.37, 1 RCT, 51 women). There were no comparative data for clomiphene citrate. There was no evidence of a significant difference in LBR between IVF and IUI alone (OR 1.96, 95% CI 0.88 to 4.36, 1 RCT, 113 women), 40.7% with IVF versus 25.9% with IUI. In studies comparing IVF versus IUI+SO, LBR per woman did not differ significantly between the groups among treatment-naive women (OR 1.09, 95% CI 0.74 to 1.59, 2 RCTs, 234 women) but was significantly higher in a large RCT of women pretreated with IUI + clomiphene citrate (OR 2.66, 95% CI 1.94 to 3.63, 1 RCT, 341 women). These three studies could not be pooled due to high heterogeneity (I2 = 84%). There was no evidence of a significant difference in multiple pregnancy rate (MPR) or ovarian hyperstimulation syndrome (OHSS) between the two treatments (OR 0.64, 95% CI 0.31 to 1.29, 3 RCTs, 351 women; OR 1.53, 95% CI 0.25 to 9.49, 1 RCT, 118 women, respectively).