One of the aspects that patients take into account when looking for the best fertility clinic is their success rates for in vitro fertilization cycles. However, this success rate depends not only on the clinic but also on other factors such as the age of the woman or the assisted reproduction technique for example.
Below you have an index with the 6 points we are going to deal with in this article.
Predictive success factors
To determine the success rates of in vitro fertilization (IVF), different aspects must be taken into account. Among them we highlight the following:
- Women's age
- is the most important factor for the success of IVF. It is vitally important to know that as a woman's age increases, the quantity and quality of her eggs decrease. For this reason, women under 39 years of age obtain better results, although after 35 years of age the results are somewhat lower.
- IVF with own or donor eggs
- IVF cycles performed with egg donation have higher success rates because eggs from young donor women are used..
- Seminal quality
- fertilization can be altered if there are seminal alterations such as asthenozoospermia or teratozoospermia. In these cases, intracytoplasmic sperm injection (ICSI) may be the solution.
- egg and/or embryo freezing
- Currently, the vitrification technique offers high survival rates, although both embryos and eggs can be altered. This could have a negative effect on the outcome of IVF.
- Embryo quality and selection
- It is necessary to make an adequate classification of the embryos in order to choose the one with the greatest implantation power for the transfer to the woman's uterus. For this purpose, preimplantation genetic diagnosis (PGD) and time-lapse are some of the advanced techniques of embryo selection that offer higher success rates.
- Number of transferred embryos
- In most cases, the transfer of a single embryo should be considered to avoid multiple pregnancies, an undesirable effect on assisted reproduction techniques. However, it must be taken into account that the greater the number of embryos transferred, the higher the probability that at least one of them will implant and give rise to a pregnancy.
- Fertility clinic
- the working protocol in each reproduction center is different, so their success rates are not the same. In addition, the training and experience of the embryologist constitute one of the most important predictive factors in the success of the treatment.
Bodyweight, obstetric history, medication protocol, or the number of previous cycles are other aspects that alter the success rates of fertility treatments.
As we can see, there are numerous factors that can influence the outcome of IVF, either individually or by combination of several. Therefore, it is necessary to keep these aspects in mind for a first cycle, but also to try to improve them for the following IVF cycles.
Importance of the woman's age
As mentioned before, a woman's age has a substantial influence on the outcome of fertility treatments.
As the woman's age progresses, her quality and quantity of eggs decreases, and consequently, the success rate of in vitro fertilization declines.
- Women under 35: the rate of gestation by transfer is about 43 percent and the rate of delivery by transfer is about 21 percent.
- Women aged 35-39 years: have a probability of becoming pregnant of about 37% and a birth rate of about 16%.
- Women 40 years of age or older: the probability of pregnancy reaching term decreases to about 7% by transfer. The rate of gestation by transfer is around 24%
As we can see, success rates drop dramatically as women age, mainly due to loss of oocyte quality. This is why egg donation is so important for these women, as it can be the solution to their infertility problem.
In brief, we could say that the percentage of birth with own eggs varies from 20 to 7% depending on age. Therefore, women over the age of 35 are advised to consider egg donation as an option.
Gestation rates vary from about 38% when using own eggs to 54% when resorting to donor eggs, and the rate of pregnancy at term (delivery rate) goes from 22% (own eggs) to 32% when resorting to egg donation.
When egg donation and surrogacy are used, success rates can be as high as 70%. However, in most destinations, surrogacy is only available if the intended mother has a justifiable medical reason.
IVF or ICSI
Many people prefer to perform ICSI rather than conventional in vitro fertilization because they believe that, by inserting semen directly into the egg, the likelihood of pregnancy increases.
However, the rates of pregnancy and delivery by transfer performed using IVF are 39.5% and 22.9% respectively and if we apply the ICSI are around 38% and 22%.
As we can see, the variations are not drastic, but there is a general increase when IVF is applied. However, the application of one or the other technique will depend on the cause of infertility, especially the male factor, as there are pathologies such as obstructive azoospermia or severe asthenozoospermia that necessarily require the application of ICSI.
ICSI is also necessary when preimplantation genetic diagnosis (PGD) treatment is performed. The birth rate per transfer in a PGD cycle is close to 32.6%.
Embryos vitrification or freezing can also vary success rates. Thus, the rate of birth by transfer of cryopreserved embryos from their own oocytes is close to 18% and if they come from donor eggs is 22.5%. These fresh rates are 22% and 32% respectively, so these indicate that the cryopreservation of embryos slightly decreases success rates.
FAQs from users
Can pregnancy be achieved in the first ivf cycle?
The outcome of an IVF treatment depends on numerous factors such as the age of the woman, the technique used, the clinic, etc. Therefore, depending on all of them, it will be more or less likely to achieve pregnancy on the first attempt.
In some cases, gestation is achieved quickly and at the first attempt. However, in other situations, two, three or four IVF treatments are necessary to achieve pregnancy.
Is a woman's age important for IVF success?
Yes. As a woman's age progresses, her ovarian reserve decreases, especially from the age of 35. Besides, the quality of the oocytes is also affected, so achieving a pregnancy with one's own oocytes can be complicated in elderly women, although not impossible.
Is there a maximum number of IVF attempts a woman can undergo?
No. However, it is necessary to rely on the prognosis of the woman and on the statistics of the results.
Therefore, when deciding whether more IVF attempts should be made, it is essential to evaluate the results obtained in previous cycles. If pregnancy has not been achieved in three or four in vitro fertilisation treatments, it is advisable to change the reproductive strategy.
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