Intrauterine insemination - known more familiarly as IUI - is a procedure with a long record in fertility care but now enjoying a resurgence in popularity. IUI was most commonly used with donor sperm in cases of male infertility, but that approach was superseded in the mid-1990s by the sperm injection technique of ICSI. Today there has been an upturn in its use, first as a favoured path to pregnancy for single and lesbian women, and next as the preferred first-line treatment in cases of unexplained infertility.
Most cases of infertility can be explained, either by abnormalities in the male partner or in the female; maybe problems with sperm (too few, too sluggish) or with hormones (irregular cycles, absent periods). But there are many cases - as many as one in three - which defy diagnosis and are simply bundled together by clinics as ‘unexplained infertility’. Although no specific diagnosis can be found, such cases may yield to treatment and the just-published European guidelines on unexplained infertility list IUI with hormonal stimulation as first-line treatment. The evidence in favour, say the guidelines, is ‘strong’.
Today, however, the most prominent patient groups to benefit from IUI are single women and lesbian couples. The latter, like so many patients using fertility techniques today, are unlikely to be biologically infertile, but are unable to conceive naturally because they have no male partner. IUI in these patient groups - and in couples with unexplained infertility - is usually performed with donated sperm and is an increasingly popular treatment. Indeed, the latest data from the regulator of the UK’s fertility sector, the HFEA, show that IUI treatments with donor sperm increased from 5810 to 7069 between 2019 and 2021, a rise of 22%. In its 2022 report, the HFEA said that this increase ‘was driven by single patients, and patients in female same-sex relationships’.
This trend has led to an increased demand for donor sperm in the UK. Unlike the dire predictions from the early 2000’s, the British men have proven to be generous and altruistic, answering the calls for increased donations. London Sperm Bank has been the British success story for the past decade and is the leading provider of British donor sperm. From nearly 20,000 applicants annually, over 200 new donors from broad and diverse backgrounds are made available through an online catalogue every year. With the most stringent regulatory framework in the world, the British donor sperm is safe, proven high quality, and easy to obtain, with the London Sperm Bank’s wide network of collaborating HFEA licensed clinics in the UK.
As with most fertility treatments, predicting success is not an exact science. Studies show that results are better when the female partner has had a short course of ovarian stimulation with fertility drugs, and, as in all cases and in all types of infertility, the chances of pregnancy decline with advancing female age. While ovarian stimulation before IUI raises success rates, it also raises the risk of multiple pregnancy, so ultrasound monitoring of the ovaries is essential.
A recent large study from London Women’s Clinic has reviewed almost 9000 IUI treatments in 3333 consecutive patients treated between 2004 and 2016. No other clinic can claim such a detailed record over such a long period of time and results showed that almost one in ten patients (8.9%) had a baby after just one treatment. When the treatment course was extended over six attempts, delivery rates as high as 66% could be expected.
However, as in many studies looking at the outcomes of different fertility treatments, this LWC study found that the age of the patient was crucial in determining success, with overall live birth rates declining steadily with advancing female age. For example, live birth rates from one insemination were found to be 12.5% in the under 35s, 9.7% in the 35–37s, 8.2% in the 38–39s, 5.4% in the 40–42s, but only 0.4% in those aged 43 or above. Almost all the patients in the study were either single (45%) or lesbian (42%) women, with a further 12% female partners in heterosexual relationships.
An important review of more than 30,000 IUI treatments in UK patients with unexplained infertility recorded a birth rate of around 12%, which also increased cumulatively with additional IUI treatments. The cumulative birth rates associated with IUI is the reason that the London Sperm Bank, and most clinics, including the London Women’s Clinic, recommend a short course of up to six IUI treatments for fertility patients, not just one. The review also found IUI more cost-effective than IVF in delivering one live birth and was associated with a lower risk of maternal and neonatal complications. Success rates in single women and couples in same-sex female relationships are considerably higher, usually because of their younger age and their normal fertility.
The new European guidelines recommending IUI as first-line treatment in cases of unexplained infertility mark another step forward for this long tried and tested treatment. The recommendations, mainly for reasons of cost and convenience, prefer IUI over IVF in these cases, a conclusion which will be controversial to some but is now underpinned by strong guideline evidence. For its part, IVF is only recommended after a course of unsuccessful IUI, with its use based on patient age, duration of infertility, previous treatment, and previous pregnancy. As in all fertility treatments, the chances of success decline with advancing maternal age, so IUI is likely to be less effective in cases of age-related infertility (Figure 1, HFEA data)
London Sperm Bank has the largest selection of British donor sperm available for IUI treatment. In collaboration with London Women’s Clinic, a specialist centre with the largest donor insemination program in the UK, and with experience for over a decade treating single women and lesbian couples, the path to IUI treatment with donor sperm has never been easier and faster.
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