Everything you need to know about IVF success rates:

• Under the age of 35, success rates are 40–50% per transfer; over 40, they drop to just 7–13%.
• Single embryo transfer drastically reduces risks for both mother and child.
• With normal sperm quality, IVF shows better results than ICSI.
• IVF treatment itself does not increase the risk of miscarriage – it corresponds to the age-specific natural rates.
• Preimplantation genetic testing allows for the targeted selection of chromosomally healthy embryos.

If you and your partner are considering in vitro fertilisation (IVF), one of the first questions you might ask is: What are my chances of success? IVF is one of the most widely used forms of medically assisted reproduction, and for many couples it offers real hope. Thanks to advances in reproductive medicine, outcomes have improved dramatically in recent years. But results vary, and factors such as a woman’s average age, egg quality, sperm health, and overall wellbeing all play an important role.

This article explains the current IVF success rates, how age and other factors affect your outcome, and what you can do to improve your own chances of success.

IVF Success: A Story of Progress

When IVF was first introduced in the early 1980s, the pregnancy rates per cycle were only around 6%. For couples facing infertility, that meant many attempts with little certainty of success. Today, however, IVF is one of the most effective forms of assisted reproductive technology.

In 2019, 5,993 couples underwent IVF or ICSI treatment, resulting in 2,204 live births — which corresponds to about 3% of all births in Switzerland. The vast majority of cycles were ICSI (84%), while conventional IVF accounted for 15%. Success rates are typically reported per embryo transfer or per cycle: for example, the live birth rate per embryo transferred was 21.2% after a fresh cycle and 24.1% after a frozen-thawed cycle.

This progress is due to:

• More precise ovarian stimulation that produces a higher number of oocytes and is tailored to each woman’s hormone levels and ovarian reserve.
• Advanced laboratory techniques such as ICSI (intracytoplasmic sperm injection), which allows fertilisation even with severe male infertility.
• Cryopreservation: with modern vitrification, more than 95% of frozen embryos survive and can be used in later transfer cycles.

Together, these developments have turned IVF into a cornerstone of modern human reproduction.

IVF Success Rates by Age

Despite these advances, a woman’s age remains the single most important factor for IVF success. Egg quality declines naturally over time, which reduces the likelihood of implantation and increases the risk of miscarriage.

• Under 35 years: Women in this group have the best outlook. The pregnancy rate per embryo transfer is about 40–55%, and cumulative birth rates reach up to 86% after several cycles.

A large study with over 6,000 patients shows: After six IVF cycles, up to 86% of women under 35 were able to give birth. Even with a cautious estimate, the figure was still 65%. By comparison, for women over 40, the likelihood after six cycles was only 23–42%.

• Ages 35–37: Success rates drop to around 25–40%. Swiss and US data show that live births occur in about 32% of cases in this age group, compared with 42% in women under 35.
• Ages 38–40: The rate falls further to 20–27%. At this stage, oocytes are more likely to carry chromosome abnormalities, which increase miscarriage risk. Data from the US confirm this trend: Among women aged 38 to 40, IVF treatments resulted in a live birth in only about 22% of cases – compared with nearly one third in women aged 35–37.
• Over 40 years: The chances of success fall sharply to 7–13% per cycle, while miscarriage rates climb to over 40%. For women aged 41–42, live birth rates are about 12%; by age 43–44 they drop to 5%, and over 44 they are just 1%.

If you’d like to learn more about treatment options and realistic chances after 40, see our dedicated article on IVF success rates over 40

IVF or ICSI – Which Is More Effective?

The development of ICSI revolutionised the treatment of male infertility by enabling fertilisation even with very poor sperm quality. However, when sperm quality is normal, conventional IVF can actually yield better outcomes:

• Fertilisation rates: 58% with IVF vs. 53% with ICSI
• Live births: 47% with IVF vs. 43% with ICSI
• First pregnancy: 33% with IVF vs. 27% with ICSI

This means ICSI is invaluable when male infertility is severe, but it is not automatically the better choice in every case.

What If It Doesn’t Work the First Time?

It’s common for couples to hope IVF will succeed on the first attempt. While that does happen, many need more than one transfer cycle. The first attempt typically results in pregnancy in 30–48% of cases, depending on age. But the chances of success increase significantly over time:

• After two cycles, 54–61% of couples achieve pregnancy.
• After three cycles, cumulative birth rates rise to 61–67%.

This is why most fertility specialists recommend planning several treatment cycles from the outset.

Key Advances in IVF

Cryopreservation of Embryos

Freezing embryos has transformed IVF treatment. Extra embryos from one cycle can be safely stored at -196°C and transferred later at the optimal time. This reduces the physical and emotional burden of repeated stimulation and allows couples more flexibility.

Single Embryo Transfer (SET)

In the past, transferring multiple embryos was common, which led to high rates of multiple births. Today, most clinics in Switzerland recommend single embryo transfer. According to the Federal Statistical Office (FSO), the rate of multiple pregnancies after IVF has dropped from 17.4% in 2002 to just 2.8% in 2023.

This reduction has enormous benefits, lowering the risks of premature birth, low birth weight, and pregnancy complications.

At the Cada fertility clinic in Zurich, we also follow this approach to ensure the safest possible outcome for both mother and child.

Lifestyle and Male Fertility: How You Can Make a Difference

While age and genetics can’t be changed, lifestyle has a clear impact on IVF outcomes. Research shows that nutrition, physical activity, sleep quality, and exposure to environmental toxins all influence fertility. A balanced diet rich in vegetables, whole grains, and healthy fats supports hormone balance and egg quality, while maintaining a healthy weight helps reduce risks. Avoiding smoking and reducing alcohol intake can also improve both oocyte and sperm health.

Supplements such as folic acid are strongly recommended before starting IVF, and some studies suggest antioxidants may support sperm quality. Regular but moderate exercise helps circulation and reduces stress, while good sleep habits support hormonal regulation.

It’s also important to look at male fertility. Poor sperm quality contributes to infertility in almost half of cases. In milder cases, insemination (IUI) may be recommended before moving to IVF or ICSI. In severe cases, ICSI is the best option because it bypasses natural barriers to fertilisation. Where sperm quality is extremely limited or absent, sperm donation may be discussed as an alternative, though it is carefully regulated in Switzerland. Addressing male fertility alongside female factors ensures couples achieve the best possible chances of success with IVF or ICSI.

Factors That Influence IVF Outcomes

Beyond age and lifestyle, other factors can influence IVF results:

• Egg reserve and hormones: Blood tests (AMH, FSH) and ultrasound scans determine the number of available oocytes.
• Embryo quality: Growing embryos to the blastocyst stage (Day 5) helps select the healthiest ones for transfer.
• Genetic testing: PGT-A and PGD allow for the detection of chromosome abnormalities, reducing miscarriage risk and improving success rates in selected cases.