IVF Eggs and Embryos to Live Birth – Rates

IVF Eggs and Embryos to Live Birth – Rates

Question: What percentage of all Eggs become Babies?

Answer: 10% – 20%, as a basic average.


Question: What percentage of all Embryos become babies?

Answer: 30% – 40%, 1/3 as a basic average.


Understanding IVF Success Rates: From Eggs to Babies

For couples facing fertility issues, in vitro fertilization (IVF) offers a beacon of hope. IVF has emerged as a popular and effective solution for those struggling to conceive naturally. However, the journey from egg retrieval to a successful pregnancy is fraught with variables, and understanding the success rates at each stage can help manage expectations. Here, we break down the journey of IVF treatment from the initial stage of retrieving mature eggs to the final goal of achieving a live birth.


From Eggs to Embryos: The IVF Process Explained

The IVF process begins with the stimulation of the ovaries, followed by the retrieval of eggs. Not all eggs retrieved will be suitable for fertilization; only mature eggs are used. The overall fertilization rate for mature eggs in IVF treatments typically stands at about 80%. This means if 10 mature eggs are retrieved, approximately 8 will be successfully fertilized.

Once fertilization occurs, the next critical phase is the development of these fertilized eggs into blastocysts, which are the first stages as embryos. Statistically, about 40% of fertilized eggs reach the blastocyst stage. Thus, continuing with our example, out of the 8 fertilized eggs, around 3 or 4 will develop into blastocysts.


Chromosomal Normalcy and Its Impact

A key factor in the potential success of a blastocyst is its chromosomal makeup. Typically, about 60% of blastocysts will have the normal number of 46 chromosomes (euploid embryos). The classic examples of abnormal chromosome numbers, 47 chromosomes, are Trisomy resulting in Down, Edward and Patau syndromes. Carrying the statistical analysis forward, this means about 2-3 of those three or four blastocysts will be chromosomally normal.


The Final Hurdle: Achieving a Live Birth

The ultimate measure of IVF success is the live birth rate per embryo transfer. For euploid embryos, the likelihood the euploid embryo transfer to the womb is successful, eventually resulting in a live birth, is around 60%. This 60% also factors in things like miscarriage. Thus, transferring one of these normal embryos gives a fairly good chance of pregnancy.


Calculating the Odds: What Percentage of Eggs Become Babies?

Given these stages and rates, we can calculate the expected outcomes from IVF starting with the number of mature eggs. The formula for mature eggs to live birth, considering all aforementioned factors (fertilization, blastocyst formation, and euploidy rates, followed by live birth chances), is approximately:

Mature Eggs×0.8×0.4×0.6×0.6=12%

This calculation suggests that for every 100 mature eggs retrieved, about 12 might result in a live birth.


From Eggs to Embryos to Babies: A Closer Look at the Numbers

Start with the Number of Mature Eggs, then:

Mature Egg Fertilization Rate: 80%

Fertilized Egg to Blastocyst (Embryo): 40%

Of All Embryos, the number that are 46C Embryo (normal chromosome number of 46 – euploid): 60%

Live Birth per 46C Embryo transfer (considering miscarriage rate): 60%

Formula for Mature Eggs to Live Birth Using the Above number: (Mature Eggs x .8) x .4 x .6 x .6 = 12%

Formula Embryo/Blastocyst to Live Birth Using the Above number: (All Embryo/Blastocyst x .6) x .6 = 36%


Variability in Success Rates

It’s crucial to note that these figures are averages derived from multiple studies and diverse IVF clinics. Success rates can vary significantly based on the clinic’s technology and approach, as well as individual factors affecting the patients, such as age. Generally, younger women tend to have better outcomes with IVF and success rates decrease as women age into their 30s and beyond.



Navigating the world of IVF can be complex and emotionally challenging. Understanding the statistical journey from egg retrieval to live birth can help set realistic expectations for couples undergoing this treatment. While the averages provide a general guide, each couple’s experience can vary widely, influenced by many factors including the expertise of the clinic and the specific health profiles of the individuals involved.