IVF Success Rates Explained

Choosing a fertility clinic can feel overwhelming, and many patients naturally look at **success rates** first.

However, comparing clinics based on a single percentage can be misleading.

One clinic may advertise a **70% success rate**, while another reports **45%**—yet the second clinic may actually achieve better results for patients like you.

The key is understanding **what the numbers measure** and whether you're comparing similar patients.

What Does "IVF Success Rate" Mean?

There is no single IVF success rate.

Clinics may report several different outcomes, including:

Clinical Pregnancy Rate

The percentage of embryo transfers that result in a pregnancy confirmed by ultrasound.

This is encouraging, but **not every clinical pregnancy results in a live birth**.

Live Birth Rate

The percentage of treatment cycles or embryo transfers that result in the birth of a baby.

This is generally considered **the most meaningful measure of IVF success**, because it reflects the ultimate goal of treatment.

Implantation Rate

The percentage of embryos that successfully implant in the uterus.

This number is mainly used by fertility specialists to evaluate embryo performance rather than to compare clinics.

Cumulative Live Birth Rate

Some clinics report the chance of having a baby **after using all embryos created from one egg retrieval**, including both fresh and frozen embryo transfers.

Many experts consider this one of the most useful statistics because it reflects the outcome of an entire IVF cycle rather than a single embryo transfer.

Why Can Success Rates Be So Different?

A clinic's published success rate depends heavily on **who they treat**.

For example:

A clinic treating mostly women under 35 with good ovarian reserve will naturally report higher success rates than a clinic specializing in women over 40 or patients with multiple previous IVF failures.

That does **not** necessarily mean the first clinic provides better care.

Age Has a Major Impact

One of the strongest predictors of IVF success is **maternal age**.

As women get older:

• egg quality gradually declines,
• fewer embryos are chromosomally normal,
• implantation rates decrease,
• miscarriage rates increase.

This is why reputable clinics usually publish results by age group rather than one overall success rate.

Typical categories include:

• Under 35
• 35–37
• 38–40
• 41–42
• 43+

Always compare results from patients in **your own age group**.

Success Depends on More Than Age

Many factors influence IVF outcomes, including:

• Ovarian reserve (AMH and antral follicle count)
• Egg quality
• Sperm quality
• Sperm DNA fragmentation
• Body weight and general health
• Smoking
• Endometriosis
• PCOS
• Uterine abnormalities
• Previous IVF history
• Whether embryos have undergone genetic testing (PGT)

No clinic can accurately predict your chance of success using age alone.

Fresh vs Frozen Embryo Transfers

Some clinics report separate success rates for:

• Fresh embryo transfers
• Frozen embryo transfers (FET)

Frozen transfers often appear to have higher success rates.

However, this does **not** necessarily mean frozen embryos are better.

Patients undergoing frozen transfer often:

• have reached the blastocyst stage,
• have embryos suitable for freezing,
• may have undergone genetic testing,
• transfer embryos in a hormonally optimized cycle.

These factors can improve outcomes independently of freezing itself.

Does Genetic Testing Affect Success Rates?

Yes.

Some clinics routinely perform **PGT-A (Preimplantation Genetic Testing for Aneuploidy)**.

PGT-A identifies embryos with the correct number of chromosomes, allowing clinicians to prioritize embryos with the highest likelihood of implantation.

Because chromosomally normal embryos are selected for transfer, clinics performing large numbers of PGT-A cycles may report higher implantation rates or lower miscarriage rates.

However, this does **not** necessarily mean IVF itself is more effective, and PGT-A is not recommended for every patient.

When comparing clinics, always check whether published success rates include PGT-tested embryos.

Questions to Ask Before Comparing Clinics

Instead of asking:

**"What is your IVF success rate?"**

Ask:

• Is this **clinical pregnancy rate** or **live birth rate**?
• Is the result reported **per egg retrieval**, **per embryo transfer**, or **per patient**?
• Does it include **fresh transfers**, **frozen transfers**, or both?
• Are results reported by **age group**?
• Does the clinic routinely perform **PGT-A**?
• What are the success rates for **patients similar to me**?

These questions will give you a much more realistic picture of what to expect.

Don't Compare Percentages Alone

Imagine two clinics.

**Clinic A**

• Mostly treats women under 35
• Average patient age: 32
• Live birth rate: **62%**

**Clinic B**

• Specializes in women aged 40+
• Average patient age: 41
• Live birth rate: **32%**

At first glance, Clinic A appears much better.

But if you're 41 years old, Clinic B may actually have more experience treating patients with your profile and could be the better choice.

Context matters more than the headline percentage.

Bboom Tip

A clinic's published success rate is only meaningful if you understand **who was treated, what outcome was measured, and how the results were calculated**.

The best clinic isn't necessarily the one with the highest advertised percentage—it's the one with strong outcomes for patients whose age, fertility history, and medical profile are similar to yours.

When choosing a clinic, look beyond the numbers. Ask how they would personalize treatment for _your_ situation, not the average patient's.

**Related reading**

• _How to Choose a Fertility Clinic_
• _IVF Step by Step_
• _IVF vs. ICSI: What's the Difference?_
• _When Should I Freeze My Eggs?_
• _Egg Quantity vs. Egg Quality_