Success rates achieved for in vitro fertilization treatments (IVF)

The real success of an in vitro fertilization (IVF) treatment is not only to achieve a pregnancy in the woman or couple with fertility problems.

What is really important is to achieve the birth of a healthy baby. For this reason, the most important success rates in assisted reproduction are delivery rates and live newborn rates.

Annually, the Spanish Fertility Society (SEF) publishes the results from all Spanish assisted reproduction clinics, which we are going to specify throughout this post (National Registry of Activity 2021-SEF Registry

IVF Success Factors

The most important factor influencing the outcome of IVF is the woman's age. As a result, success rates are often split between younger and older women.

However, there are many other aspects to consider in determining the likelihood of success of in vitro fertilization, such as:

Oocyte Quality

a woman's age decreases her ovarian reserve and also the quality of her eggs.

Fertilization technique

we differentiate between conventional IVF and ICSI (intracytoplasmic sperm injection). Although both have very similar success rates, ICSI has some specific indications, such as severe male factor.

Semen quality

some seminal alterations such as asthenozoospermia or teratozoospermia can hinder fertilization. In these cases, ICSI may be the solution.

Egg or embryo freezing

the vitrification technique used today offers high survival rates. However, the quality of the eggs and embryos may be somewhat affected and influence the outcome of IVF.

Embryo selection

it is essential to properly classify the embryos according to their quality and to choose the one with the highest implantation potential for the transfer. Advanced embryo selection techniques, such as preimplantation genetic testing (PGT) and time-lapse, offer higher success rates.

Number of embryos transferred

transferring more than one embryo increases the probability that at least one of them will implant and result in gestation. However, this also increases the likelihood of multiple pregnancy, something that nowadays is avoided at all costs due to the risks it poses to both the mother and the fetuses.

Cause of infertility

depending on the reason that is causing sterility in the couple, the probability of pregnancy will be higher or lower.

Medication protocol

the hormones the patient receives during ovarian stimulation and endometrial preparation will determine the number of eggs obtained for IVF and the characteristics of the uterus at the time of transfer, respectively.

Fertility clinic

each reproductive center has a different work protocol. In addition, the expertise of embryologists is critical to the success of the treatment.

Factors involved in IVF success rates

As we can see, there are many factors that, individually or collectively, can influence the outcome of IVF. Therefore, it may happen that, after a first unsuccessful IVF, pregnancy is achieved in successive attempts due to better control or improvement in some of these aspects.

Delivery rates

As we have said, there are a multitude of ways to express the results of a fertility treatment: implantation rate, pregnancy rate, delivery rate, live newborn rate, and so on.

Here we are going to detail the delivery rates for each embryo transfer, since this is a data provided by the SEF and that we consider important for assisted reproduction patients.

In addition, we will also differentiate these results according to the woman's age and the fertilization technique used in the IVF cycle.

Conventional IVF

In 2021, 4,395 conventional IVF cycles were performed in Spain (compared to 4,344 cycles in 2020), and results expressed as delivery rate per transfer are as follows:

Women < 35 years old

31.6%

Women 35-39 years old

27.2%

Women ≥ 40 years

12.8%

Success rates for conventional IVF

As we can see, age is a determining factor in the success of IVF.

IVF-ICSI and mixed IVF

The ICSI technique is the most widely used technique in all laboratories to fertilize eggs with sperm, as 41,120 IVF cycles were performed with this procedure in 2021.

In some cases, specialists decide to fertilize half of the eggs with the traditional method (conventional IVF) and the other half with the ICSI technique. This is what is known as mixed IVF.

The SEF statistical report collects the results of both procedures together, i.e. IVF-ICSI and mixed IVF. The delivery rates per transfer, in this case, were as follows:

Women < 35 years old

34.6%

Women 35-39 years old

25.2%

Women ≥ 40 years

12.8%

Birth rates from IVF-ICSI amd mixed IVF

If you are not sure about the differences between conventional IVF and IVF-ICSI, we recommend reading the following article: What is the difference between IVF and ICSI?

Other statistics

Other data provided by the SEF in its annual report are reasons for the procedure, percentages of single, double and triple transfers, pregnancy rates, miscarriage rates, multiple pregnancy rates, etc., for each type of assisted reproduction treatment.

Among these data, we will now discuss those that we consider important.

Reasons for the procedure

The main indication for IVF treatment in 2021 was female factor. Of the couples who used IVF in order to become parents, 41.2% had low ovarian reserve, uterine malformations, obstruction of the fallopian tubes, and so on.

The remaining indications for IVF were, from highest to lowest, as follows:

• Mixed causes.
• Male factor.
• Infertility of unknown origin.
• Woman without a male partner.
• Couples with communicable infectious diseases.

General success rates

By way of summary, the success rates achieved in 2021 for IVF treatment were generally as follows:

Pregnancy rate

34.4% (embryo transfer pregnancies).

Delivery rate

25.2% (embryo transfer deliveries).

Single birth rate

91.1% (single deliveries per total number of deliveries).

Twin delivery rate

8.7% (twin births per total number of births).

Miscarriage rate

23.9% (miscarriages per number of pregnancies).

Live newborn rate

27.4% (babies born by embryo transfer).

Other general success rates of IVF

Neither the age of the woman nor the number of embryos transferred is taken into account here, so we recommend consulting the SEF National Activity Registry 2021 for more detailed information.

As Dr. Gorka Barrenetxea tells us:

The rates that all assisted reproduction centers should consider are the healthy birth rates. These are the rates that we try to transmit to the National Registry of the Spanish Fertility Society.

Other IVF alternatives

Unfortunately, it can happen that a woman does not achieve pregnancy after several embryo transfers in different IVF cycles.

At this point, it will be necessary to make a decision and look for alternatives depending on the characteristics of each couple, since there are other treatments and complementary techniques that can increase the chances of pregnancy.

Specifically, PGT (pre-implantation genetic testing) and using donor eggs are the treatments indicated for women of advanced maternal age who cannot achieve pregnancy with their own eggs. As the following data indicate, transfer delivery rates can increase considerably:

IVF with own eggs

25.2%

IVF with PGT

39.7%

IVF with donor eggs

41.5%

Other variations of IVF and their success rates

Embryo transfer delivery rates with PGT and ovodonation are very similar. The reasons are obvious: PGT ensures the transfer of genetically healthy embryos with higher implantation potential and. IF using donated eggs, the eggs come from healthy and young girls, and are of very good quality.

However, it should be noted that here we are considering success rates per embryo transfer. The problem with PGT is that it is not always possible to obtain healthy embryos for transfer and sometimes the cycle has to be canceled.

For this reason, women with very low ovarian reserve or whose eggs accumulate genetic mutations due to age will have to resort to IVF with oocyte donation if they wish to become mothers.

Finally, although the age of the man does not affect the outcome of IVF equally, there is also a slight increase in the success rate of IVF with donor sperm with respect to IVF with the partner's own gametes.

FAQs from users

How many IVF attempts are recommended for a 39-year-old woman with good ovarian reserve?

The recommended number of attempts will depend on how many blasts are obtained in the first cycle. Depending on this, the situation will be studied together with the patient and, taking into account the results and her family planning, the most appropriate decisions will be made for each case. Normally up to 3 ovarian stimulations can be performed.

The percentage of aneuploidies increases exponentially with age. Aneuploidies are alterations that occur in sperm, eggs or embryos during their early development and can result in embryos with an incorrect number of chromosomes. Chromosomal abnormalities can cause miscarriages and are also associated with genetic diseases.

For this reason, having a good ovarian reserve at an advanced reproductive age is not synonymous with having a good oocyte quality and this may be the reason why pregnancy is not achieved to term.

Due to the above, the most advisable thing for a 39-year-old woman with reproductive problems would be to perform a PGT-A test, which is the genetic study of aneuploidy of embryos cultured up to day 5 (blastocyst stage). This test makes it possible to detect and discard for transfer those embryos with numerical anomalies.

To what extent does it depend on the patient whether embryo implantation is successful or not? Are there any specific precautions to be taken?

There are no specific measures that patients can take, except to follow the specific indications given by their physician regarding medication. It is true that sometimes it is recommended to avoid exertion or to take relative rest after the transfer. This is a measure which, from a psychological point of view, helps patients to feel fully involved in their cycle.

Is it easy to achieve successful in vitro fertilization the first time?

As we discussed in the article, the outcome of IVF depends on numerous factors. Therefore, depending on them, it will be more or less likely to achieve pregnancy in the first attempt.

There are women and couples who achieve gestation quickly, while others need two, three or four IVF treatments to achieve pregnancy.

Can I get pregnant by IVF if I am 39 years old?

The woman's age is a factor that greatly influences the success rate of IVF. This is because, with the passage of time, a woman's ovarian reserve decreases, especially after the age of 35.

Although natural pregnancy is complicated at 39 years of age, it is possible to achieve it with IVF. The probability of success will depend fundamentally on the quantity and quality of the eggs.

When is the beta result reliable after IVF?

It is usually indicated to wait at least 15 days after embryo transfer to obtain a reliable pregnancy test result. However, there are cases, such as when blastocysts are transferred, where the test can be reliable as early as 10 days after transfer.

Recommended reading

If you want to learn more about the success rates of assisted reproduction techniques, we encourage you to access the following article: Success rates of assisted reproduction treatments.

If you are interested in finding a fertility clinic with good success rates, we recommend you to read the following article with tips that will help you in your search: How to choose the best-assisted reproduction clinic for me?