In this guide, we'll explore the various IVF success factors that can impact the likelihood of a successful pregnancy. While there are many factors that impact IVF success rates, measuring the likelihood of getting pregnant is difficult to do. Influencing factors include things like the efficacy of your practitioner, the method and technology used, your personal health, lifestyle, and other complicating factors like age.
There's no perfect formula to determine your IVF success rate, nor is it possible to guarantee any outcomes. But we can look at many of the contributing variables as an educational resource on how IVF success can vary from case to case. In this guide, we'll cover factors like age, number of cycles, procedure type, and complicating factors to see how different variables impact IVF success rates.
Success Rate Definitions
With a complex, multi-step process like IVF, there are many ways to measure success in each phase of the process.
The Society for Assisted Reproductive Technology (SART) publishes comprehensive yearly reports that aggregate IVF data from all reported outcomes from U.S. clinics. SART calculates success rates based on your chances of a live birth if you were to do one egg retrieval and publishes both cumulative success rates and initial success rates.
Here's the difference between these types of success rates so you understand what different sets of data mean.
Initial Success Rates
Initial success rates provide insight into the chances of IVF success for the first embryo transfer procedure. This data looks at the success of a single embryo transfer procedure. Initial success rates calculate how likely it is for one egg retrieval and the first, initial embryo transfer to result in a live birth.
Cumulative Success Rates
This rate is a more holistic look at the entire fertility journey, rather than a single procedure. Cumulative IVF success rates offer a broader perspective on the chances of IVF success throughout the entire fertility journey, taking into account multiple embryo transfers. They calculate how likely a patient is to eventually have a live birth from a single egg retrieval cycle and one or more embryo transfers.
Many people who undergo IVF may need to do multiple egg transfers in the event that they do not get pregnant after the first try. Additionally, some may ultimately do more transfers with banked embryos for subsequent pregnancies. It's important to look at both percentages to get a more comprehensive understanding of what to expect throughout your IVF journey.
IVF Success Rates by Age
Chances of IVF success are closely tied to age, which is one of the most influential factors on IVF outcomes. Age is often used to organize both cumulative and initial IVF success rates. Positive outcomes typically lower with age, largely due to lower quality eggs and lower fertilization and implantation rates.
To understand the exact impact, we've broken down the data into age ranges to see the different experiences of women in various age groups. However, just because success rates are lower doesn't mean there's no chance of success for women past the age of 35. Your fertility doctor can help identify solutions to help improve your odds regardless of age.
IVF Success Rates Under Age 35
Initial success rate: Women who are under 35 years old have a live birth rate of 41.4% following the first embryo transfer cycle.
Cumulative success rate: In this same age range, the statistical chances that one egg retrieval cycle will eventually result in a live birth (accounting for all transfers) is 55.6%.
IVF Success Rates by Ages 35-37
Initial success rate: Between ages 35 and 37, the chances that the first embryo transfer cycle leads to a live birth is 31.6%.
Cumulative success rate: The cumulative success rate jumps to a 40.8% chance that one egg retrieval cycle will eventually result in a live birth (accounting for all transfers).
IVF Success Rates by Ages 38-40
Initial success rate: For those ages 38 to 40, the chances that the first embryo transfer cycle leads to a live birth is 22.3%.
Cumulative success rate: Overall, women in this age group have a 26.8% chance that one egg retrieval cycle will eventually result in a live birth (accounting for all transfers).
IVF Success Rates by Ages 41-42
Initial success rate: Women who are 41 or 42 years old have an 11.7% chance that the first embryo transfer cycle leads to a live birth.
Cumulative success rate: In that same age group, the statistical chances that one egg retrieval cycle will eventually result in a live birth (accounting for all transfers) is 13.4%.
IVF Success Rates Over Age 43
Initial success rate: For those ages 43 and over, the chances that the first embryo transfer cycle leads to a live birth is 3.8%.
Cumulative success rate: And in the same age range, the statistical chances that one egg retrieval cycle will eventually result in a live birth (accounting for all transfers) is 3.9%.
IVF Success Rates by Number of Cycles
Understanding the IVF transfer success rate for each cycle can help manage your expectations and provide insight into the success rates of IVF treatments. It's helpful to understand the rate of success for each embryo transfer cycle in order to mentally prepare your expectations. In fact, research shows that the success rate of IVF increases with each cycle.
First Cycle of IVF
According to one study, the average success rate for the first IVF attempt is 29.5%. This percentage was the average across all age groups. The results did vary based on age, with the highest success rate (32%) attributed to women under 40.
Second Cycle of IVF
The second cycle of IVF actually has a slightly lower success rate, likely because the selected egg may be of a lower quality than the one used in the first cycle. On the plus side, the odds could be improved thanks to an improved learning curve and potential adjustments.
Third Cycle of IVF
The third cycle of IVF actually comes with the highest chance of a successful pregnancy. The odds after the cumulative effect of three cycles of IVF becomes 45% to 53% across age ranges.
As a result, completing three full cycles is often recommended as the most effective amount to balance cost and likelihood rather than continuing beyond that threshold. Talk to your fertility doctor to establish a comprehensive IVF treatment plan based on your individual situation.
IVF Success Rates by Procedure Type
There are several different types of IVF procedures, which can also impact success rates. Your fertility doctor will advise you on the pros and cons of each one and determine the best procedure for your unique needs. Different IVF procedures can impact the overall success rates, so it's crucial to work with your fertility doctor to determine the best approach for your specific situation. Here's an overview of some of the most common types so you can get a sense of what to expect.
Mini IVF
Also called minimal stimulation IVF, “Mini IVF” is a less invasive option for women who have fewer eggs, a concern tied to older age groups such as those who are older than 35.
According to one study, Mini IVF has higher success rates than that of conventional IVF. Success rates for Mini IVF were ⅓ higher in women 35 to 40 years old, and they were twice as high in women over 40.
Lupron Trigger IVF
Lupron trigger IVF is used to avoid triggering ovarian hyperstimulation syndrome (OHSS) in patients, which can be caused by the use of hCG shots. In-depth success rate comparisons are not well studied, but there is overall equivalency shown in regard to oocyte yield per cycle, embryo quality per cycle, and pregnancy rates per cycle. In fact, most clinicians now do either lupron or a hybrid hCG/lupron trigger to lower the risk of OHSS, particularly since there appears to be no significant difference in success rates.
IVF with Genetic Testing
This is an expensive and controversial procedure that has not been rigorously studied until recently. And while there is a common misconception that preimplantation genetic testing for aneuploidy, PGT-A, improves patients’ chances for successful IVF, studies actually reveal a more neutral conclusion. Women with three or more good quality blastocysts had approximately the same cumulative live-birth rate for both conventional IVF and PGT-A testing.
IVF with Frozen Blastocysts
The type of blastocyst used during IVF can also impact pregnancy rates. Data shows that there is improved implantation and pregnancy rates in frozen embryo transfer cycles involving vitrified blastocyst versus fresh blastocyst transfers during stimulated cycles.
For instance, some studies have revealed a better embryo survival rate and a lower rate of cooling damage.
IVF Success Rates with Complicating Factors
Some women experience complicating factors that may or may not impact the likelihood of success with IVF treatment. While some of these issues are within the patient's control to mitigate, others are not. But an experienced fertility doctor can help you navigate these challenges to maximize the chance of pregnancy as much as possible.
IVF for Smokers
Smoking can negatively impact IVF outcomes in multiple ways, both for female as well as male partners. One result is that smoking lowers the endometrial thickness in the days leading up to ovulation; in fact, on average, the endometrial lining of a smoker is 2 mm thinner than a non-smoker. By embryo transfer day, this lowers the chance of a successful implantation and pregnancy.
This endometrial damage, along with problems with follicle formation caused by smoking, can lower live birth chances by 28%. Additionally, smoking during IVF also results in higher miscarriage rates. Another study reveals that even donor eggs from non-smokers are subject to these lower success rates if the IVF patient is a smoker.
Finally, the impact of smoking on IVF success rates isn't limited to women. A study tracking male partners revealed a success rate of 21.1% for non-smoking males compared to just 7.8% for smoking male partners.
IVF with Obesity
Obesity also has an adverse effect on IVF pregnancy rates. Just how much of an impact depends on body mass index (BMI). For women with a BMI between 30.0 and 34.9, the odds of a live birth after IVF drop by 37% compared to those with a BMI between 18.5 and 24.9. A BMI between 35 and and 39.9 lowers the odds by 61%, and a BMI of 40 or higher reduces the chances of pregnancy by 68%.
Part of the reason for these lower success rates is that obesity can reduce both egg and embryo quality, as well as fertilization rates. The uterine lining can also be adversely affected by too much weight. Achieving a lower BMI could help improve patient success rates.
IVF with PCOS
PCOS does not automatically result in a lower IVF success rate. In fact, studies reveal that PCOS patients have similar success rates as those without it. One of the key differentiators is weight. One study revealed that women with PCOS who maintain a healthy weight were twice as likely to have a successful pregnancy compared to women who are obese.
IVF with Endometriosis
Endometriosis is one of the most common contributing factors of infertility in women, accounting for as much as 50%. And while many studies have been conducted on endometriosis and IVF success rates, the results are unclear. There are many individual factors, including the severity of the endometriosis, which can impact the success rates of IVF.
IVF with Donor Eggs
IVF success rates using donor eggs are quite high, which is encouraging since 12% of IVF patients use them for the embryo transfer. Success rates average around 52% and can dramatically increase the odds of a successful pregnancy for women who are 40 years or older. A donor can help improve egg quality or circumvent ovarian failure due to early menopause. And for women who are worried about genetically transmitted diseases, a donor egg can eliminate this risk.
Conclusion
The success rate statistics for IVF are incredibly complicated and impacted by many variables, some that are within our control and many that are not. For the best results, consult with a qualified fertility doctor that uses the latest in technology and stays up to date with the most current research in the field. By familiarizing yourself with the various factors that influence IVF success rates, you can make more informed decisions about your fertility journey and set realistic expectations.
Oma Fertility's team of specialists can help you maximize your fertility success rates through a combination of medical procedures and lifestyle consulting.
Last Updated: Jun 15, 2023 12:00 AM
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