In Vitro Fertilization (IVF) or Intrauterine Insemination (IUI)? Which is the most suitable for the couple?

In vitro fertilization or intrauterine insemination? What is the most suitable procedure based on the couple’s fertility characteristics?

When a couple goes to a fertility center because pregnancy doesn’t come naturally, they undergo a series of tests. At the end of the exams, the preferable path is proposed to the aspiring parents, which should generally start from the  simplest if the characteristics of the couple allow it.

In vitro fertilization

In vitro fertilization, commonly called IVF, is a very common infertility treatment which involves the use of specific drugs to stimulate the maturation of several follicles. Once the oocytes are mature, they are recovered during a short operation ( pick-up ) under anesthesia. The oocytes are then fertilized in vitro in the laboratory.   The embryos obtained are allowed to grow  for 3-5 days before one or more are inserted into the uterus or vitrified for subsequent transfer.

Who is a good candidate for IVF?

IVF is the most successful infertility treatment for nearly all patients, including those with the following:

• ovulation problems
• tubal damage/blockage
• endometriosis
• pelvic adhesions
• poor seed quality
• unexplained infertility
• prolonged infertility.
• It can also be used to enable preimplantation genetic testing (PGT) of embryos.

IVF success rates

Age is the main factor that most influences IVF success rates. Women under the age of 35 may have an approximately 50% chance of having a baby with their first egg retrieval and subsequent embryo transfer. Women who do not get pregnant after the first IVF cycle still have a very good chance of getting pregnant in the second, third and even following IVF cycles.

According to the Society for Assisted Reproductive Technology (SART) clinical report , the cumulative average percentage odds of birth from IVF by age are:

• 55% for women under the age of 35
• 40% for women aged 35 to 37
• 26% for women aged 38-40
• 13% for women aged 40 to 42
• 4% for women over the age of 42

The cumulative success rate for carrying a baby increases for all women with additional IVF cycles. Success rates also depend on:

• type of patient,
• diagnosis, protocols used,
• amount of ovarian stimulation,
• laboratory quality,
• use of additional techniques,
• number of embryos transferred,
• other factors.

T he main factor limiting success with IVF is female age . The increasing age of the woman is linked to a progressive reduction of the ovarian reserve. The presence of low ovarian reserve is possible even in young women and in these cases often the only successful option is the use of heterologous fertilization (egg donor.

What are the advantages, disadvantages and risks of IVF?

In vitro fertilization is much more successful than intrauterine insemination (IUI), another commonly used fertility procedure.

Unlike IUI, it can help bypass almost any type of infertility problem. It can also allow access to pre-implantation diagnosis. Furthermore, in vitro fertilization has a greater ability to prevent twin births through the transfer of single embryos (SET = single embryo transfer).

It is a technique that allows you to shorten the time to get pregnant  because the success rates are higher than with IUI.

IVF can also be beneficial for couples who want more than one child. Often the excess embryos obtained during the stimulation and fertilization cycle are frozen to try to have other children in the future.

The disadvantages are obviously that IVF (or ICSI) costs much more, in terms of emotional, physical and financial commitment. IUI involves only mild ovarian stimulation, some monitoring and outpatient insemination.

IVF requires much stronger ovarian stimulation, frequent daily monitoring, egg retrieval under anesthesia, fertilization in the laboratory, embryo development in vitro, almost always cryopreservation (freezing) for embryo preservation, and finally the subsequent transfer of the embryo into the uterus following a specific endometrial preparation .

How to choose?

The choice is generally made with the help of the doctor (or the fertility center) who offers the couple the most suitable treatment based on their characteristics .

Various factors  such as age (especially of the woman), fertility diagnosis and family medical history are involved in the choice. If the couple’s conditions are such that even a homologous IVF could give very little results, it could be appropriate to consider resorting to gamete donation (oocytes or sperm).

The decision also involves the need or not to resort to pre-implantation diagnosis , the number of embryos to be obtained and frozen.

Whatever treatment you want to go through, it’s essential that the couple is supported throughout the process by a psychotherapist specialized in this area. 

When should IVF be used directly?

When the chances of pregnancy with IUI are very low and relatively higher with IVF.

For example, when the tubes are blocked or damaged, in the case of moderate to severe endometriosis, in the presence of pelvic adhesions and in the presence of a more than mild factor of male infertility.

Women should resort directly to in vitro fertilization when they have little time to seek pregnancy due to age, reduced ovarian reserve , when there is a need to resort to preimplantation diagnosis and when there is a need to resort to heterologous .

The choice between IUI or IVF should be made by each patient together with their fertility specialist.

 Intrauterine insemination (IUI)

Intrauterine insemination is a type of insemination that has been performed for decades. For some couples it may be an option to try before resorting to IVF.

The general principle is that the best treatment should be adopted for any given patient by considering a number of factors.

The age of the woman and the type of infertility diagnosis are the two main considerations for choosing a treatment . But there are other factors to consider including wait times and costs.

What is intrauterine insemination?

Briefly, intrauterine insemination (IUI) is a fertility procedure in which the seminal fluid is capacitated in the laboratory to make it optimal and transferred to the uterus using a specific catheter through the cervix.

Insemination is performed just before the woman ovulates. This can occur during a natural cycle or in a cycle where drugs are used to stimulate ovulation. These drugs can be taken orally like clomid, or through injections.

IUI is often suggested by doctors as one of the first fertility treatments. This is because it is relatively simple, cheaper, and increases pregnancy rates when done with ovarian stimulation.

Which couples are candidates for IUI?

The IUI is proposed to couples in case of:

• unexplained infertility;
•  mild to moderate male infertility;
• stage I-II endometriosis and selected cases of stage III-IV of the American Fertility Society (AFS) classification, especially after surgery;
• repeated failures of pregnancy induction with ovulation stimulation and targeted intercourse;
• sexual and coital pathologies
• cervical factor.
• Prevention of the risk of transmission of infectious diseases in serodiscordant couples.

IUI is also a good option for those without fertility issues, including same-sex couples.

The male factor is very important in the selection of couples for IUI.

After capacitation (process performed in the laboratory on the collected seminal fluid, to select and concentrate the progressively motile and morphologically normal spermatozoa from the total sample), the minimum indispensable number of   progressively motile spermatozoa must be  1-2 million and as a percentage of physiological forms that of  4% according to  WHO criteria .

If we consider the semen collected before capacitation, the lower limit based on the literature available at the moment is:

• 3 million motile sperm ( Strandell et al., 2003 ),
• 5 million ( Khalil et al., 2008 )
• 10 milioni (Kahn et al., 1992, Van Voorhis et al., 2001).

Ultimately, after capacitation in order to resort to IUI, there is a tendency to have at least a concentration of spermatozoa between 0.8 and 5 million/ml and 4% of normal morphology.

What is the success rate of an IUI?

IUI success rates depend on age, cause of infertility, use of fertility drugs, and number of cycles performed.

The pregnancy rate with intrauterine insemination in women under the age of 35 is approximately 8%-10% per cycle.

The cumulative pregnancy rate (total pregnancies) after two cycles is about 18% and with 3 cycles about 25%.

Pregnancy rates decrease after 3 unsuccessful cycles.

After 6 cycles of ovarian stimulation and IUI, the cumulative or total number of pregnant women is about 35%.

Starting at age 38, pregnancy rates per cycle are usually 5% or less.

For couples with unexplained infertility, IUI has twice the success rate of trying natural routes.

What are the advantages, disadvantages and risks of IUI

The IUI procedure is relatively safe, simple, and noninvasive. It is also much faster and cheaper than IVF,

The main disadvantage of IUI is the significantly lower birth rate compared to IVF.

Ovulation-stimulating drugs such as clomiphene (CLOMID) can also . have side effects

The primary risk of IUI when accompanied by ovarian stimulation is twin pregnancy . Multiple pregnancies represent a complication of assisted reproduction treatments because they involve risks for the mother and the children ( preterm birth , disability, infant mortality, and health problems for the mother).

This risk can be substantially reduced if only 2 or at most 3 follicles are matured during ovarian stimulation.

If it is limited to 2 or 3 oocytes, the rate of twin pregnancies ranges from approximately 8% to 10%. And the rate of triplets is 1 in 200.

When to stop IUI attempts and switch to IVF

Each region in Italy provides for a maximum cycle (in the public) of IUI treatments before moving on to IVF. They can be on average 3 or 4.

Many doctors place a limit of three failed IUI cycles, but others can try up to six before moving on to more invasive treatments.