Time Intervals in IUI Cycles Influences Success Rates

Home » IUI » Time Intervals in IUI Cycles Influences Success Rates

Time intervals in IUI cycles influences success rates

Time intervals between semen production, initiation of analysis, and IUI significantly influence clinical pregnancies and live births

A retrospective study of couples who underwent Intrauterine Insemination (IUI) cycles was carried out to explore the potential for improvements in outcomes, using IDEF mapping of the laboratory process, and statistical analysis.

The couples for this study were recruited from the Centre for Reproductive Medicine, at the Antwerp University Hospital in Belgium, between April 2013 and March 2018. A total of 662 couples were included, covering 1729 IUI cycles.

Exclusion criteria for males included abstinence less than 2 days or greater than 7 days, cryopreserved semen and semen preparation not carried out by density gradient centrifugation, while women older than 43 were also excluded from the analysis.

The IUI cycles was carried out with both natural (spontaneous) cycles and low dose stimulated cycles, using either clomiphene citrate or gonadotrophins. Semen analysis was performed within 60 minutes of ejaculation and processed using a two-step discontinuous density gradient method. All prepared samples had a final total inseminating motile count ≥ 2 Million with inseminating volume kept between 0.3 to 0.5mL.

Initial results showed that of the 1729 cycles, 254 (14.7%) resulted in a positive hCG leading to 206 live births (11.9%). Regarding other outcomes, the biochemical rate was 0.8%, with 12.4% spontaneous/induced abortions, two ectopic pregnancies, one immature and 2 stillborn. Interestingly a spontaneous LH surge (> 30 IU/L) was only seen in 19 of the 1729 cycles, with the other 1710 cycles requiring a hCG trigger shot.

Statistical analysis of the initial data found no difference in the concentration, motility or morphology of the sperm between the non-pregnant and pregnant groups. On the other hand age, was significantly linked to pregnancy outcome, with every 1 year increase in age linked to a 4% decrease in odds of pregnancy, for both male and females.

Advanced statistical analysis using the Youden index to identify the optimal time intervals, found that a limit of 21 minutes for the time between semen production and analysis, with a final limit of 107 minutes between semen production and IUI, produced the maximum Youden index.

Using these two time intervals to analyse the original data again, in a generalized linear effects model, a limit of 21 minutes between semen production and analysis approximately doubled the odds of a pregnancy outcome (positive hCG, clinical pregnancy, live birth). When the time between semen production and IUI was 107 minutes or less, the odds of a pregnancy outcome was 1.6 times greater. This result remained consistent even after adjusting for both male and female ages.


To ensure the maximum IUI success rate per cycle, the time between sperm production to analysis, and then IUI should be less than 21 minutes and 107 minutes respectively. This increases the odds of IUI success by 2 times, for first interval to analysis, and 1.6 times for the total interval to IUI.


  1. Semen was not assessed for DNA fragmentation
  2. Size of study too small to analyse unstimulated and stimulated cycles independently of each other

Similar studies

Horta F, et al. (2019). Male ageing is negatively associated with the chance of live birth in IVF/ICSI cycles for idiopathic infertility. https://doi.org/10.1093/humrep/dez223

Fauque P, et al. (2014). Clinical success of intrauterine insemination cycles is affected by the sperm preparation time. https://doi.org/10.1016/j.fertnstert.2014.03.015

Song G J, et al. (2007). Location of semen collection and time interval from collection to use for intrauterine insemination. https://doi.org/10.1016/j.fertnstert.2007.01.051

Yavas Y and Selub M R, (2004). Intrauterine insemination (IUI) pregnancy outcome is enhanced by shorter intervals from semen collection to sperm wash, from sperm wash to IUI time, and from semen collection to IUI time. https://doi.org/10.1016/j.fertnstert.2004.04.061


Low Sperm Count Overview

Low sperm count, also known as oligospermia or oligozoospermia, happens when a man has 15 million or less sperm per millilitre (mL) of…. Read more

Causes of Low Sperm Count

The causes of low sperm count fall into 3 main categories: medical, environmental and lifestyle. Medical causes of low sperm count include…. Read more

Questions or comments?