Learn which factors can influence the success of an IUI and what you can do yourself to increase your chances.

Key Facts on How to Increase Your IUI Chances

  • IUI is a treatment option for mild male infertility or unexplained infertility.
  • The pregnancy rate per IUI cycle is 10–20%, depending on factors such as the woman’s age, sperm quality, and underlying cause of infertility.
  • Typically, 3–6 cycles are recommended before considering alternative treatments.
  • A healthy diet and relaxation can positively influence your chances of success.
  • Close collaboration with your fertility clinic and strict adherence to your treatment plan are essential.

Often the First Step for Mild Fertility Issues

The journey to parenthood isn’t always straightforward. When natural conception doesn’t occur, intrauterine insemination (IUI) is often the first step in fertility treatment. But what factors affect the success of this method, and how can you actively improve your chances? In this article, we explore the science behind IUI and provide evidence-based insights and practical tips.

What is IUI?

Intrauterine insemination (IUI) is a form of assisted reproductive technology (ART). In simple terms, IUI involves introducing prepared sperm directly into the woman’s uterus at the time of ovulation, maximising the chances of fertilisation.

What is the Pregnancy Rate for IUI?

IUI success rates vary depending on the treatment approach and individual factors. Studies show that the pregnancy rate per cycle in natural (unstimulated) cycles is around 8–10%, while in stimulated cycles, it can rise to 15–20%. After multiple cycles (3–6), the cumulative pregnancy rate increases to 40–60%.

What Factors Influence IUI Success?

The success of IUI depends on various factors, including:

1) Woman’s Age:

  • Women under 35 have an average success rate of 15–20% per cycle, whereas for women over 40, the rate drops to 5–10%.
  • A retrospective analysis of 4,246 insemination cycles showed that pregnancy rates remained stable in women up to 40, between 7.5% and 10%. However, success rates declined significantly with increasing age.
  • Due to the low probability of success, IUI is rarely performed after the age of 40.

2) Sperm Quality:

  • The quality of sperm directly impacts IUI success.
  • Lifestyle factors such as diet, smoking, and alcohol consumption significantly affect sperm quality.
  • Antioxidants like vitamins C and E have been shown to improve sperm motility and morphology (Showell et al., 2014).
  • A study by van Weert et al. found that the pregnancy rate per IUI cycle with prepared sperm is 10–20%, depending on sperm motility and morphology.

3) Hormonal Stimulation:

  • Some studies suggest that controlled ovarian stimulation with gonadotropins improves pregnancy rates compared to natural cycles, particularly for women with ovulation disorders.

How to Improve Your Chances of Success with IUI

While IUI is a medical procedure, there are steps you can take to optimise your chances:

Healthy Lifestyle:

A balanced diet supports egg development and improves fertilisation chances.

  • Research suggests that a Mediterranean diet, rich in fresh fruit, vegetables, whole grains, fish, and healthy fats, improves fertility in both men and women (Chavarro et al., 2007).
  • Maintaining a healthy weight is crucial. A study by Bellver et al. (2010) found that women with a BMI between 18.5 and 24.9 have significantly higher success rates in fertility treatments, including IUI.
  • Moderate exercise improves circulation and supports reproductive health (McKinnon et al., 2016).
  • Sufficient sleep (7–8 hours per night) is essential for hormonal balance and ovulation (Lin et al., 2024).

Stress Management:

  • Chronic stress can negatively impact fertility by disrupting hormone balance and implantation.
  • A study by Domar et al. (2011) found that women who participated in a mind-body programme increased their pregnancy rate after fertility treatment by 32%.
  • Psychological support can improve emotional well-being and enhance treatment outcomes (Matthiesen et al., 2011).

Additional Factors:

Learn more about IUI and how to increase your chances of a successful IUI:

Who is IUI Suitable For?

IUI is a relatively simple and cost-effective fertility treatment, suitable for couples struggling to conceive naturally. It is often the first treatment option before more advanced methods like IVF.

Common indications for IUI include:

  • Unexplained infertility – when no clear cause of infertility is found.
  • Mild male infertility – including low sperm count, reduced motility, or mild morphological abnormalities.
  • Endometriosis – particularly mild cases of endometriosis, although IVF or ICSI is often preferred.
  • Cervical factor infertility – when cervical mucus prevents sperm from reaching the uterus.
  • Ejaculation disorders – such as retrograde ejaculation.
  • Immunological infertility – where antibodies in cervical mucus affect sperm function.
  • Sperm donation – for cases of male infertility or genetic conditions.
  • Single women and lesbian couples – who wish to conceive using donor sperm.
  • Sexual dysfunction – when intercourse is not possible for medical or psychological reasons.
IUI is not suitable for severe infertility cases such as azoospermia (absence of sperm) or blocked fallopian tubes. In these cases, IVF or ICSI is recommended.

The IUI Procedure Explained

  1. Sperm Preparation: On the day of insemination, a sperm sample is collected (either from the partner or a donor). The sperm is processed in the laboratory to remove non-motile sperm and debris, improving the concentration of high-quality sperm. In addition, techniques such as the ‘swim-up’ method or density gradient centrifugation can be used to select the highest quality sperm.
  2. Ovulation Monitoring: IUI can be performed in a natural cycle or with hormonal stimulation. Ultrasound scans and blood tests monitor follicle growth and hormone levels to determine the optimal insemination time. IUI is often combined with hormone treatment to promote the growth and maturation of several follicles and increase the likelihood of successful fertilisation. Hormonal stimulation can take the form of tablets (e.g. clomiphene citrate) or injections (e.g. gonadotropins).
  3. Insemination: The prepared sperm is introduced into the uterus via a thin, flexible catheter. The procedure is quick, usually painless, and performed in the clinic.
  4. Post-Insemination: Your doctor will advise on the next steps and when to take a pregnancy test.

Takeaway: A Healthy Lifestyle Boosts Success

IUI is a valuable fertility treatment, and maintaining a healthy lifestyle, along with expert medical guidance, can significantly improve your chances of conception. Open communication with your fertility specialist ensures the best possible outcome.

At our fertility clinic in Zurich, we have helped many couples achieve pregnancy through IUI.

If you’d like to explore whether IUI is right for you, simply book an appointment at Cada Fertility Clinic and take the first step towards fulfilling your dream of parenthood.