IUI Success Factors and How to Improve IUI Success Rates

Last Updated on July 8, 2021

Intrauterine insemination (IUI) is a relatively low-risk infertility treatment giving couples a painless and non-invasive option to conceive. The procedure involves placing sperm directly into a woman’s uterus putting it closer to the egg. IUI increases the chance of conception for couples who may be experiencing difficulty getting pregnant.

There are various factors that can come into play which can affect IUI success rates. For instance, the woman’s age, underlying infertility diagnosis, the use of fertility drugs, if any, and other underlying fertility concerns can all make a difference. Success rates following Intrauterine insemination can also depend on the reason for needing the fertility treatment.


What is the success rate of IUI

Overall, women have a 10-20 % IUI success rates on first try with each Intrauterine insemination cycle. Of course, based on this, it’s easy to assume that the more cycles you get, the greater your chances of conception.

Single women or couples who wish to give IUI a try are usually recommended three cycles of treatment. However, in some cases, this number can be increased to six treatment cycles. That said, the chances of success also drop with subsequent cycles.

If pregnancy is not achieved after 3 IUI cycles, your treatment plan may need some reevaluation. That is why most fertility experts will move onto other types of procedures after three unsuccessful tries at IUI.

IUI success rates by age

Typically, IUI success rates tend to decrease in women over the age of 40 and in others who have not been able to conceive after 3 treatment cycles.

As age progress for the female patient, the chance of successful IUI without the use of fertility drugs decreases. For some others, even younger patients may only experience success with the assistance of fertility drugs. And since age is considered one of the biggest determiners of the success rate, here is a breakdown of how Intrauterine insemination success rates can change with age.

Woman’s agePregnancy ratesDelivery rates
20-30 years17.6%13%
31- 35 years13.4%10%
36-38 years13.3%9%
39-40 years10.6%7%
40+ years5.4%3%

Given the very low IUI success rates for women in the over 40 group, a lot of fertility experts recommend that these patients forgo IUI altogether and opt for IVF instead. For those who do wish to proceed ahead with this procedure, doctors often recommend that only one cycle be attempted. After the first initial unsuccessful cycle, many would recommend moving on to other fertility treatments.

IUI with injectables success rate

Medication is sometimes used to bump up the odds of pregnancy, especially when a couple has been trying to conceive for 12 to 18 months. One way to help IUI treatment is to use injectable medication.

Injectable fertility medications contain either follicle stimulating hormone (FSH) alone or in combination with luteinizing hormone (LH). Injecting FSH with or without LH works on the ovaries to produce multiple follicles or cysts containing eggs. This procedure is known as superovulation.

Injectable drugs are administered on the third day of the menstrual cycle and are used for six to ten days. During this time the patient is monitored via bloodwork and ultrasounds to see how the eggs are growing and developing.

Once the lead egg, also called a follicle, reaches 20mm with the uterine lining thickness of at least 7mm, a trigger shot is administered. The trigger shot contains the human chorionic gonadotropin (hcG) hormone which triggers an ovary to mature and release an egg. The IUI is then scheduled 36 hours after the trigger medication is injected.

Once again, age is a crucial factor with younger patients responding better to fertility drugs than their older counterparts.

Age bracketSuccess rate per cycle
35- 40 years10%
40 years and above5%

IUI success rate with PCOS

About 10% of women of childbearing age suffer from PCOS where hormonal imbalances result in the adrenal glands or ovaries producing excess male hormones. At the same time, women with the condition produce too little FSH so that follicles which protect the maturing egg remain small and inactive. PCOS also present the challenge of the endometrial lining becoming overly thick resulting in irregular or extremely heavy menstruation.

However, women with PCOS generally make excellent candidates for treatment with Intrauterine insemination, presenting success rates that are far better than for other groups.

IUI that is paired with gonadotropins for PCOS sufferers shows success rates between 14-26% per cycle. This is higher than almost any other patient class working with Intrauterine insemination treatment. That said, patients with PCOS who take gonadotropins during treatment also have a very high risk of multiple births. Here are what study statistics for IUI success rates with PCOS in women under the age of 38 looks like:

Treatment typeLive birth per cycleMultiples per pregnancy
Clomid or Letrozole with IUI5-7%9%
Gonadotropin with IUI20-26%36%

How to improve IUI success rates

If you seem to fit the profile for the ideal Intrauterine insemination candidate, then you would want to make sure that you do everything to make your treatment successful. Here are some tips you need to consider to improve your IUI success rates.

1. The best candidates for IUI

Since the success rates are only moderate at best, IUI may not be the right procedure for everyone. The best candidates for Intrauterine insemination are cases where the following apply:

  • Mild to moderate male infertility instead of severe male infertility
  • Female partner has cervical mucus problems
  • Irregular or absent ovulation
  • Unexplained infertility
  • Using donor sperm
  • PCOS sufferers
  • Lesbian couples

2. The type of artificial insemination procedure

Artificial insemination is the broader term for certain procedures of which IUI is just one option. The other popular one is intracervical insemination (ICI). In terms of success rates, IUI has shown better results than ICI with the main difference between the two being the condition of the sperm.

The sperm used for ICI insertion, for instance is unwashed. This simply means that all the natural fluids and cells are held together with the sperm instead of being washed or removed. IUI, on the other hand, uses washed sperm where sperm cells are separated from the seminal fluid through density gradient. The sample is then washed and added to a cryopreservative medium.

Unwashed sperm, as used in ICI is feasible for placement in the cervix. But if the same were to be used for IUI, it could cause uterine cramping, so is never used for an intrauterine insemination.

Washed sperm samples, as used in IUI treatment, are believed to raise the success rate of the procedure.

3. Age of the female patient

Finding success with Intrauterine insemination largely depends on the woman’s age. As seen above, the younger the patient, the higher the chance of a successful pregnancy.

4. Use of fertility drugs

Some women, especially those over the age of 35, may be advised to use fertility medication to induce superovulation. This state allows the body to release more eggs during ovulation to boost the chance of pregnancy. Using fertility drugs that first start off with oral options like Clomid alongside IUI can raise the chance of a successful pregnancy.

Where the Clomid-IUI combination doesn’t show positive results for the initial treatment cycles, doctors may recommend using injectable medications for later cycles.

5. The number of inseminations per cycle

To boost the chance of pregnancy with intrauterine insemination, your fertility expert may do two instead of one insemination per cycle. The result for this remains mixed as some research indicates that two inseminations may be better than one. At the same time, other studies show that a single insemination per cycle has a higher rate of success than two inseminations per cycle.

6. After the procedure

Research-based findings show that women who lie down for fifteen minutes after the IUI procedure were 10% more likely to conceive during that cycle than others who got up following the insemination.

Out of the 400 couples studied for this research, the group that rested showed 27% IUI success rate while women who got up sooner after the insemination showed a success rate of 17%.

7. Using donor sperm

Where male infertility factor is present, using donor sperm for IUI can boost the chance of pregnancy. Couples who opt for this option may suffer with the male partner having no sperm or having a poor semen analysis. There could also be a genetic problem which could be inherited from the male.

8. Lifestyle considerations

While IUI may well be the beginning of your fertility treatment, it is equally important to take care of yourself before and after the procedure. Creating a healthy environment for the pregnancy is vital for IUI success. As you move ahead with your treatment, keep the following considerations in mind:

  • Pare down your exercise regimen keeping things simple and low impact
  • Support a healthy pregnancy by taking prenatal vitamins
  • Eat well to promote overall health after iui for success
  • Stay hydrated and toxin-free by drinking lots of water
  • Find ways to reduce stress (a lot of evidence shows stress can reduce your chances of getting pregnant)


Trying to conceive can quickly become an emotional struggle for couples and repeated attempts can leave many people exhausted in various capacities. Getting in touch with a qualified fertility expert is a good starting point and if IUI is your choice of treatment, then you should know all the factors that come into play when considering this option. If your reproductive endocrinologist considers you a good candidate, then knowing that there are ways to boost IUI success rates can help you achieve the pregnancy you so desire.