Intrauterine Insemination (IUI) 

What is Intrauterine Insemination (IUI)?

Intrauterine insemination (IUI) is a form of assisted reproductive treatment in Singapore in which laboratory-prepared sperm is placed directly into the uterus around the time of ovulation. This approach aims to increase the number of motile sperm that reach the fallopian tubes, thereby improving the likelihood of fertilisation.

The procedure is typically timed with the help of ultrasound scans to monitor the development of ovarian follicles. An injection of human chorionic gonadotropin (hCG) is often used to trigger ovulation, allowing the insemination to be performed at the most fertile point in the cycle.

IUI may be recommended in cases of unexplained infertility, mild male factor infertility, or difficulties with sperm delivery. It can be performed using a partner’s sperm or donor sperm, depending on individual circumstances.

When should I consider IUI?

IUI is a relatively simple and cost-effective fertility treatment, but its success rates are generally lower than more advanced techniques like in vitro fertilisation (IVF). It may be considered in the following situations:

• Mild male factor infertility — if a partner’s semen analysis shows slightly reduced sperm count, motility (movement), or abnormal morphology (shape), IUI may be recommended. In such cases, the sperm is specially processed to select the most motile sperm, which are then placed directly into the uterus near the fallopian tubes. This reduces the distance the sperm must travel to reach the egg, improving the chances of fertilisation.

• Endometriosis-related infertility — for women with mild to moderate endometriosis, IUI is often used in combination with ovulation induction medications and injections to encourage the development of multiple eggs. This approach can be especially effective in younger women trying to conceive.

• Ovulation disorders — IUI may be appropriate to expedite conception in women who do not ovulate regularly or young women who have a diminished ovarian reserve, provided there are no other factors impeding fertility. If ovulation induction alone is not successful, combining it with IUI can improve the chances of conception.

• Use of donor sperm — IUI can be used in cases where donor sperm is required, whether due to severe male factor infertility. 

What happens during the IUI process?

Intrauterine insemination involves several coordinated steps, each aimed at maximising the chances of fertilisation by carefully timing and preparing for ovulation and insemination.

Step 1: Ovulation monitoring 

Accurate timing is essential for IUI to be effective. Ovulation is monitored using transvaginal ultrasound scans, typically starting from day 10–12 of the menstrual cycle. These scans allow us to visualise the ovaries and measure the growth of the follicles (fluid-filled sacs containing the eggs), with follow-up scans every 2–3 days to assess follicular maturity.

When a follicle reaches a size of around 17–18mm, it is considered mature. At this point, an injection of human chorionic gonadotropin (hCG) is given to trigger ovulation. The insemination is usually scheduled about 40 hours after this injection to coincide with the expected release of the egg.

In most cases, oral medications from day 2–6 are prescribed to ensure ovulation. In some women daily hormone injections may be prescribed  to stimulate the development of multiple  follicles - this is called super ovulation. 

Step 2: Semen preparation

Around two hours before the scheduled procedure, the male partner provides a semen sample, either at home or in a private collection room at the clinic. The sample is then processed in the laboratory to select  the healthiest, most motile sperm.

If donor sperm is being used, a frozen vial is thawed and similarly prepared for insemination.

Step 3: Insemination

On the day of the procedure, patients are advised to arrive with a full bladder. A transvaginal scan is first performed to confirm ovulation.

A speculum is gently inserted into the vagina, and any cervical mucus is cleared to aid the process. The prepared sperm sample is drawn into a thin catheter, which is then carefully inserted through the cervix and into the uterus. The procedure is generally painless and does not require anaesthesia. Most women can resume normal activities immediately afterward.

Step 4: Luteal phase support and pregnancy testing 

After the insemination, hormone medications may be prescribed to support the uterine lining and enhance the chances of implantation. A pregnancy blood test is usually performed around two weeks after the procedure to determine whether the IUI was successful.

What is the difference between IVF and IUI? 

While both intrauterine insemination (IUI) and in vitro fertilisation (IVF) are assisted reproductive treatments, they differ significantly in how fertilisation occurs, the level of medical intervention involved, and their typical success rates. The choice between the two depends on the underlying fertility issue, age of the female partner, and previous treatment history.

The table below highlights the key differences between IUI and IVF:

Aspect	IUI (Intrauterine Insemination)	IVF (In Vitro Fertilisation)
Where fertilisation occurs	Inside the body, in the fallopian tubes	Outside the body, in the laboratory (petri dish)
Procedure	Sperm is prepared and placed into the uterus at ovulation	Eggs are retrieved, fertilised in the lab, and resulting embryos transferred to the uterus
Hormonal stimulation	Mild or none; oral medications or minimal injections	Intensive; daily hormone injections to stimulate multiple egg production
Level of intervention	Less invasive	More invasive
Use of laboratory techniques	Minimal	Extensive (e.g. egg retrieval, fertilisation, embryo culture)
Cost	Lower cost	Higher cost
Success rate	Lower per cycle (varies with age and condition)	Generally higher per cycle, especially in women under 35
Common indications	Mild male factor, unexplained infertility, ovulation issues, donor sperm use	Blocked fallopian tubes, severe male factor, endometriosis, repeated IUI failure, older age
Time and effort	Fewer clinic visits and simpler process	Requires more time, coordination, and monitoring

Who is a good candidate for IUI?

IUI is often recommended as a first-line fertility treatment for individuals or couples who meet certain clinical criteria. You may be a suitable candidate for IUI if you are <37 years old and if:

• You have unexplained infertility — when no clear cause of infertility is identified after basic investigations, IUI is often suggested as an initial treatment.

• There are mild male factor issues — slightly low sperm count, motility, or abnormal shape can sometimes be improved through semen processing, which makes IUI a viable option in such cases.

• You have ovulation disorders — if you do not ovulate regularly, IUI combined with ovulation induction can help increase the chances of conception.

• You have mild endometriosis — in selected cases, IUI may be considered for women with minimal or mild endometriosis, especially when paired with fertility medications.

• You require donor sperm — IUI is commonly used by single women or same-sex female couples using donor sperm.

• You are younger and have good ovarian reserve — IUI is generally more effective in women under 37 with healthy egg reserves and no significant tubal or uterine abnormalities.

However, IUI may not be suitable for individuals with blocked fallopian tubes, moderate to severe endometriosis, or significantly low sperm parameters. Your fertility specialist will assess your medical history, test results, and personal circumstances before recommending the most appropriate treatment.

What are the risks or side effects of IUI?

IUI is generally considered a safe and low-risk fertility procedure. However, as with any medical treatment, there are a few potential side effects and risks to be aware of:

• Mild cramping or spotting — some women experience light cramping or spotting during or shortly after the procedure, usually caused by the insertion of the catheter through the cervix. This typically resolves within a day.

• Ovarian hyperstimulation — if fertility medications are used to stimulate ovulation, there’s a small risk of ovarian hyperstimulation syndrome (OHSS), where the ovaries become swollen and painful. This is more likely when injectable medications are used and is monitored closely by your doctor.

• Multiple pregnancy — when ovulation induction leads to the release of more than one egg, the risk of twins or higher-order multiples increases. While some patients may see this as a benefit, multiple pregnancies carry higher risks for both mother and babies.

• Infection — although rare, there is a slight risk of introducing infection into the uterus during the insemination process. Clinics follow strict sterile techniques to minimise this risk.

Overall, most women tolerate IUI well with minimal complications. Your fertility specialist will monitor your response to medication and provide guidance throughout the process to ensure your safety.

What should I do to prepare for an IUI cycle?

Preparing well for an IUI cycle can help optimise your chances of success. Your fertility team will guide you through the medical aspects, but here are a few general steps you can take:

• Attend all scheduled appointments — regular ultrasounds and blood tests are essential for tracking your ovulation and ensuring the IUI is timed correctly.

• Take prescribed medications as directed — if your doctor has recommended fertility medications to stimulate ovulation, be sure to take them exactly as instructed. This may include oral tablets or injectable hormones.

• Maintain a healthy lifestyle — eating a balanced diet, getting regular exercise, and maintaining a healthy weight in the 2-3 months prior to conception can support your fertility. Avoid smoking, excessive alcohol, and unnecessary stress.

• Track your cycle — familiarising yourself with your menstrual cycle and ovulation patterns can help you feel more in control and understand the process better.

• Abstain from ejaculation for 2–3 days before the procedure — if using a partner’s sperm, this helps ensure an optimal sperm sample for the IUI.

• Ask questions and stay informed — don’t hesitate to raise any concerns or ask about the steps ahead. Feeling prepared and informed can ease anxiety and help you approach the cycle with confidence.

Each patient’s IUI journey may differ slightly depending on their individual fertility history, so it’s important to follow the plan tailored for you by your fertility specialist.

What can I expect after the IUI procedure?

After intrauterine insemination, most women can return to their normal daily activities immediately. The procedure is quick and minimally invasive, with little to no recovery time needed.

You may experience some mild symptoms, which are usually harmless:

• Light cramping or spotting — some women feel mild cramping similar to period pain or notice light spotting. This is typically due to the catheter passing through the cervix and should resolve within a day or two.

• Bloating or breast tenderness — these symptoms may occur due to hormonal medications used during the cycle, not necessarily the IUI itself.

• Emotional ups and downs — the two-week wait between the IUI and pregnancy test can be emotionally challenging. It’s normal to feel anxious, hopeful, or uncertain during this time.

Your doctor may prescribe medications to support the luteal phase (the second half of your cycle) and improve the chances of implantation. A blood test is usually scheduled around 14 days after the procedure to check for pregnancy.

If you experience severe pain, heavy bleeding, or fever after the IUI, you should contact your clinic, although such complications are rare.

How many IUI cycles should I try before considering other treatments?

The number of IUI cycles recommended varies depending on your age, fertility diagnosis, and response to treatment. In general, fertility specialists advise trying up to three to six IUI cycles before moving on to more advanced options like in vitro fertilisation (IVF).

Here’s a general guideline:

• Women under 35 — up to 3 to 6 IUI cycles may be attempted, especially if there are no major fertility issues or if the problem is unexplained.

• Women aged 35–40 — IUI may still be considered, but if there is no success after 3 cycles, IVF is usually recommended for higher success rates.

• Women over 40 — IVF is often considered the first-line treatment due to lower success rates of IUI and the importance of time.

If IUI has not led to pregnancy after several well-timed cycles with ovulation and good-quality sperm, it may be time to reassess your treatment plan. Your doctor will discuss your response to IUI, test results, and other factors to decide if moving to IVF or other options would give you a better chance of success.

Why does IUI not work 

Possible Reasons for IUI Failure is as follows:

1. Sperm Quality: Issues such as low sperm count, poor motility (swimming ability), or abnormal morphology (shape) can impede fertilization.
   
2. Ovulation Timing: Accurate synchronization of IUI with ovulation is vital. Irregular ovulation or misalignment in timing can lead to unsuccessful attempts.
   
3. Egg Quality: The quality of the eggs is essential for fertilization and implantation success. Women over 35 tend to experience a decline in egg quality, increasing the likelihood of IUI failure.
   
4. Uterine Factors: Anatomical issues such as uterine fibroids, polyps, or a thin endometrial lining can hinder successful implantation of the embryo.
   
5. Fallopian Tube Conditions: Blockages or damage to the fallopian tubes can prevent sperm from reaching the egg or obstruct the implantation of the fertilized embryo.
   
6. Age: Female fertility naturally decreases with age, and IUI success rates tend to be lower for women over 35.
   
7. Lifestyle Factors: Habits such as smoking, excessive alcohol consumption, and obesity, excessive overthinking or stress can adversely affect fertility.
   
8. Underlying Health Conditions: Disorders like Polycystic Ovary Syndrome (PCOS) or endometriosis can complicate the success of IUI.
   
9. Fertilization Issues: Healthy sperm and eggs do not guarantee fertilization, which may fail to occur.
   
10. Implantation Challenges: Even after fertilization, the embryo may not implant successfully in the uterine lining.
    
11. Unexplained Infertility: Some couples may face infertility without a clear cause, These couples can have reduced IUI outcomes.
    
12. Number of Cycles: Success rates can improve with multiple IUI attempts, as adjustments can be made based on previous outcomes.
    
13. Use of Frozen Sperm: While effective, IUI with frozen sperm may have slightly lower success rates compared to using fresh sperm.

What if IUI is unsuccessful and what are the next steps?

It’s natural to feel disappointed if an IUI cycle does not result in pregnancy, but this outcome is not uncommon. Fertility treatments often require more than one attempt, and many couples need several cycles before achieving success.

If you have completed a few IUI cycles without conceiving, your fertility specialist will review your overall progress and consider the following next steps:

• Repeat IUI with adjustments — depending on your age and fertility profile, your doctor may recommend trying additional IUI cycles with changes such as higher medication doses, closer monitoring, or switching to injectable hormones.

• Further diagnostic testing — if not already done, additional tests (e.g. hysterosalpingography, laparoscopy, advanced semen analysis with DNA fragmentation and HBA, or genetic screening) may be suggested to uncover any underlying issues that might be affecting success.

• Transition to IVF — if IUI is unsuccessful after multiple attempts or if new issues are identified, in vitro fertilisation (IVF) may be advised. IVF allows greater control over fertilisation and embryo development and generally offers higher success rates, particularly for older women or those with complex fertility issues.

• Explore other options — in some cases, options like using donor eggs, donor sperm, or considering surgical correction for conditions like severe endometriosis or fibroids, may be discussed.

Summary 

Intrauterine insemination (IUI) is a safe, minimally invasive fertility treatment that involves placing prepared sperm directly into the uterus to improve the chances of conception. It is often recommended for individuals or couples dealing with unexplained infertility, mild male factor issues, ovulation disorders, or those using donor sperm. 

The process involves careful monitoring of ovulation, semen preparation, and a quick, usually painless insemination procedure. While IUI offers a more affordable and less intensive option compared to IVF, its success depends on factors such as age, fertility diagnosis, and response to treatment. Most patients are advised to try several IUI cycles before considering other options like IVF. 

If you are considering IUI or exploring your fertility treatment options, schedule a consultation with Holistic Gynaecology & Fertility to receive personalised, expert guidance tailored to your needs.

Frequently Asked Questions (FAQs)