What Is IVF Success Rate? 10 Important Factors To Consider

Last Updated on March 11, 2020

Fertility clinics use the term IVF success rate to talk about how successful treatment is. People look at IVF success rate when they want to know how likely it will be to have a baby. But the term actually refers to a number of things. Success rates can be manipulated and therefore must be evaluated carefully.

Understanding IVF Success Rates

First, consider where the information about the success rates is coming from. Generally speaking, IVF success rates in the United States comes from the clinics themselves or from the Center for Disease Control and Prevention. The Society for Assisted Reproductive Technology and the American Society for Reproductive Medicine both contribute to the CDC data.

Which success rates matter? To most patients, all of the rates matter, but in reality, you should consider live birth rates only. The reason is that pregnancy rates include pregnancies that end prematurely or that don’t result in a live birth.

While pregnancy is definitely a sign of success – especially if a patient has been struggling to conceive – the ultimate sign of a successful fertility treatment is a vibrant, healthy baby. So success should mean more than just pregnancy.

At the same time, in older women, the IVF success rates can vary dramatically, and that’s why it’s so important to focus only on live births. For example, a clinic may have a very high pregnancy rate among older women, but a low live birth rate. Or, the rates may be quite high – 40% or even 50% – but only after four or five rounds. That makes a very big difference, especially in the overall cost of treatment!

So, no matter what the clinic’s success rates are, ask the clinic about their rates and what criteria they are using. Make sure you are very clear about how they got to the rate, and how many rounds on average it takes their patients to have a live birth.

IVF success rates vary in very big ways, especially when it comes to age. For this reason, consider all of the factors when it comes to IVF success, not just age. Consider the type of IVF, the clinic, the diagnosis, use of techniques such as ICSI, and history of previous births, too.

Trends in IVF Success Rates by Age

A woman’s age is the most important factor in conception if you are looking to use your own eggs. Egg quality is best under the age of 35 simply due to nature’s design. After 35, female eggs are more prone to making genetic errors, commonly described as “aneuploidy” in medical terms.

As egg quality declines with age, the success rates of IVF also head downhill. The 2017 National Summary Report on Assisted Reproductive Technology (ART) by the Center for Disease Control and Prevention (CDC) reports the following success rates in 5 different age groups:

Age <35 35-37 38-40 41-42 ≥43
Live birth rate 48.5% 43.0% 35.8% 24.9% 11.0%

You can see that women who are under 35 almost have a 50-50 chance of carrying a baby to term using IVF. However, the chance of success is halved by the age of 40.

Between the ages of 35-37 and 38-40, the live birth rate drops nearly 10%, which is also statistically significant.

Statistically, the biggest decline in live births happens between the ages of 40 and 42+. In other words, a woman who has just turned 40 has a much higher chance of conceiving and delivering a baby than a woman who has just turned 42. Of course, these numbers and trends concern women using their own eggs. With donor eggs, consider the age of the woman at the time the eggs were harvested and use that age.

Apart from poor egg quality at advanced maternal age, older women are also less likely to respond to ovarian stimulation hormones that cause the release of multiple eggs. Being able to produce a dozen of eggs significantly increases the odds of success. It allows your fertility practitioner to choose the egg with normal genetic makeup and best likelihood of implantation. In both nature and IVF, not all eggs are suitable to produce a pregnancy. Ideally, you would produce 8-15 eggs after ovarian hyperstimulation so that some of them are genetically normal and perfectly matured.

For these reasons, women aged over 40 who have a lack of viable eggs are usually recommended donor eggs to improve IVF success rates. Despite poor populational outcomes, your personal health condition may differ. Thus, it is not entirely impossible to have a pregnancy with your own eggs.

*The following reports on IVF success rate by age are base on the latest CDC data published in May 2020 (Final 2018 Data) with 20 or more transfers.

IVF success rates under 35 with own eggs (nondonor eggs)

IVF success rates at 35-37 with own eggs (nondonor eggs)

Average live births rate at 35-37 with own eggs is 42.8% in total 23777 IVF cycles. Average singleton live births is 35.1%.

Clinic Name Live Births at 35-37 Singleton Live Births at 35-37 Total Transfers at 35-37
Sum 620
Avg = 70.8 Avg = 62.5 Avg = 62.0

IVF success rates at 38-40 wtih own eggs (nondonor eggs)

Average live births rate at 38-40 with own eggs is 35.5% in total 16486 IVF transfers. Average singleton live births is 30.4%.

Clinic Name Live Births at 38-40 Singleton Live Births at 38-40 Total Transfers at 38-40
Sum 623
Avg = 65.9 Avg = 62.2 Avg = 62.3

IVF success rates at 41-42 with own eggs (nondonor eggs)

IVF success rates over 42 with own eggs (nondonor eggs)

IVF sucess rates by Number of embryos transfer

Approximately 18% of IVF deliveries in the United States are multiple births, such as twins, compared to a mere 1-2% in natural pregnancies (CDC 2016).  This is a result of transferring multiple embryos in a woman’s uterus in the hope that at least one of them implants.

However, it turns out that implanting more than one embryo does not increase your chance of pregnancy, only a chance of multiple pregnancy. In fact, the percentage of live birth rate decreases significantly as the number of embryos transferred increases.

According to the 2016 CDC report, transferring 2 embryos can lead to an 8.4% decrease in success rate while transferring 3 embryos halves your success rate.

Number of Embryos transfer 1 2 3 4+
Live birth rate 30.4% 22.0% 15.0% 11.6%

A study presented at the British Fertility Society Annual Conference and covered by The Guardian reported that transferring two embryos where one is of poor quality would reduce the chance of pregnancy by 27%. It is thought that a bad embryo is rejected by the endometrium, compromising the implantation of both embryos. Cumulative research has supported the notion that egg quality outweighs quantity.

When transferring more than one embryo, the risk of pregnancy and newborn complications also increases.1 Among IVF babies, twins are 12 times more likely than singletons to be delivered prematurely, 16 times more likely to be underweight and 5 times more likely to suffer from respiratory complications. Among IVF mothers, mothers of twins are 2.5 times more likely to have pre-eclampsia, over 8 times more likely to have premature preterm rupture of membranes and 4 times more likely to require a Caesarean section.

Average number of embryos transfers per retrieval (Nondonor eggs, New patients)

*Base on the latest CDC data published in May 2020 (Final 2018 Data) with 20 or more transfers.

Clinic Name Age <35 Age 35-37 Age 38-40 Age 41-42 Age ≥43
Avg = 1.6 Avg = 1.0 Avg = 0.7 Avg = 0.4 Avg = 0.2
Min = 1.5 Min = 0.4 Min = 0.9 Min = 0.5 Min =
ivf-authority 2.0 ivf-authority 2.0 ivf-authority 1.0 ivf-authority 1.0 ivf-authority 1.1

Fresh or frozen egg

In your first IVF cycle, you would be prescribed ovarian hyperstimulation medications that induce multiple egg production. If a good number of eggs are collected and fertilized, you would be offered the option of a fresh embryo transfer or freeze the eggs/embryos until later.

It turns out frozen embryo transfers are better as compared to fresh transfers when using your own eggs. CDC reports a 11.6% better pregnancy rate and 9.6% better live birth rate using frozen embryos. This superiority is thought to be due to ovarian stimulating hormones that render the endometrium less welcoming in the current cycle.

Cause of infertility

There are many different types of infertility problems affecting both males and females. They need to be treated differently, which are very important in maximizing your IVF success.

The severity or complexity of infertility for you and your partner as a whole is also critical. Generally, patients are characterized as “subfertile” if there is only one infertility factor such as mild endometriosis, which can be improved through surgeries like laparoscopy. However, if both partners contribute infertility factors or one partner has multiple infertility factors, the chance of IVF success is significantly decreased.

Use of technologies (PGS and ICSI)

Advanced technologies add to your IVF bill but may also make a huge difference to your success rate. Pre-implantation genetic screening (PGS) can improve implantation rate by selectively transferring genetically normal embryos. For couples with male factor infertility, Intracytoplasmic sperm injection (ICSI) can help deliver a sperm directly into the egg. Nevertheless, ICSI only improves success rate in couples with severe male infertility.

Day of embryo transfer

Depending on a particular IVF clinic’s protocol, a embryo may be transferred anytime in the next 1 to 6 days after fertilization. Currently, day 3 and day 5 are the most commonly used, but day 5 transfer offers a 10% higher success rate (CDC 2016).

Previous IVF outcome

After the first IVF cycle, only less than 30% of women have a live birth whereas 8.3% or 62.3% have a miscarriage or no pregnancy, respectively.2 What do the next cycles mean for those who did not succeed?

After 2 further cycles, those who miscarried in the first cycle are twice as likely to have a live birth compared to those with no pregnancy in the first cycle.

Competency of the clinic

Average national statistics do not represent the competency of individual clinics. A particular clinic’s success rate depends on its technology, staff experience and protocols followed.

You can check out the IVF clinics with the best success rates in the United States, or use IVF ihelper to find clinics that suit you the most.

Donor eggs and gestational carrier

Donor eggs are most often recommended to women at advanced maternal age. However, they may also be beneficial or necessary for patients who have severely damaged egg quality, such as due to cancer treatment.

Gestational carrier is an option to avoid miscarriages, pregnancy complications and improve success rates in women who have uterine abnormalities or prone to life-threatening complications during pregnancy.

Lifestyle factors

A number of modifiable lifestyle factors also contribute to IVF success rates.

  • Being overweight can reduce your fertility and put you at higher risks of miscarriage, diabetes and premature birth.3
  • The father’s weight can affect his sperm quality and hence your IVF success rates.4
  • Hypercaloric diets are associated with diabetes, obesity, and hyperlipidaemia, which reduces fertility.5
  • Smoking, alcohol drinking, drug use, environmental health are all lifestyle factors that affect IVF success.6

Conclusion

A lot goes into determining your odds of IVF success. No matter how small or big each factor is, you should try to optimize all of them for a happy outcome. Don’t forget, you can also use the success rate calculator for a personalized predication. It is also important to plan multiple full IVF cycles no matter what the first IVF cycle outcome is. 3 full IVF cycles are generally recommended to improve your cumulative success rates. About two thirds of patients will be successful after six or more cycles of IVF.

 

Resource:

1 Klitzman, R. Deciding how many embryos to transfer: ongoing challenges and dilemmas. Reprod Biomed Soc Online 3, 1-15, doi:10.1016/j.rbms.2016.07.001 (2016).

2 Cameron, N. J., Bhattacharya, S., Bhattacharya, S. & McLernon, D. J. Cumulative live birth rates following miscarriage in an initial complete cycle of IVF: a retrospective cohort study of 112 549 women. Hum Reprod 32, 2287-2297, doi:10.1093/humrep/dex293 (2017).

3 Silvestris, E., de Pergola, G., Rosania, R. & Loverro, G. Obesity as disruptor of the female fertility. Reprod Biol Endocrinol 16, 22, doi:10.1186/s12958-018-0336-z (2018).

4 Palmer, N. O., Bakos, H. W., Fullston, T. & Lane, M. Impact of obesity on male fertility, sperm function and molecular composition. Spermatogenesis 2, 253-263, doi:10.4161/spmg.21362 (2012).

5 Silvestris, E., Lovero, D. & Palmirotta, R. Nutrition and Female Fertility: An Interdependent Correlation. Front Endocrinol (Lausanne) 10, 346, doi:10.3389/fendo.2019.00346 (2019).

6 Zeinab, H., Zohreh, S. & Samadaee Gelehkolaee, K. Lifestyle and Outcomes of Assisted Reproductive Techniques: A Narrative Review. Glob J Health Sci 7, 11-22, doi:10.5539/gjhs.v7n5p11 (2015).

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