If we only got 3 eggs and all 3 fertilized, that's going to be a good outcome for that cycle. However, that is the first step of fertilization. Then, depending on the age, what we want is day 5 embryos,
Women under 38 in our IVF program have acceptable live birth rates even with only 3 – 6 eggs, do better with more than 6 eggs, and do best with more than 10 eggs. Women 38-40 and 41-42 years old have low live birth rates with low egg numbers. Success rates are much better when relatively high egg numbers are obtained.
Women who have three chromosomally-normal embryos as a result of In Vitro Fertilization (IVF) have a 94.9% chance of achieving pregnancy, research conducted by Reproductive Medicine Associates (RMA) and presented at the annual meeting of the American Society for Reproductive Medicine (ASRM) shows.
An average of ten to 20 eggs are usually retrieved for IVF, but the number can be higher or lower. You would think more eggs is always better, but that's not the case. Researchers who analyzed thousands of IVF cycles found that the magic number of eggs retrieved from IVF treatment that lead to a live birth is 15.
As a general rule of thumb, at RMA New Jersey, which has one of the best embryology labs in the country (as evidenced by the clinic's high success rates), about 80 percent of eggs will fertilize (day 1 success), and of those, about 30-50 percent will make it to the blastocyst stage (day 5 or 6).
Anywhere from 60-80% of all fertilized eggs make it to Day 3, which is when they are about 8-10 cells in size.
The average rates of egg development are as follows: Maturity – 80% of all retrieved eggs. Fertilization – 80% of all mature eggs. Embryo utilization – 30-40% of fertilized eggs/total embryos.
On average (depending on the woman's age), about 80 percent of eggs will fertilize. So if your 15 mature eggs, let's say only about 12 fertilize.
“The proportion of fertilized eggs that produce a live full-term baby (in the absence of contraceptive measures) is not known precisely, but is probably only 40% 1. The other 60% die, at all stages from fertilization to late pregnancy.
The term fertilisation failure is used when none of the inseminated eggs have fertilised, or the fertilisation rate is very low. This situation takes place in 11% to 15% of traditional IVF cycles, and in about 3% of ICSI cycles. As you can imagine, the consequences are generally very traumatic for the couple.
One is best – most of the time.
Research still shows that transferring one embryo per cycle is the safest option. Transferring two increases the chance of a multiple pregnancy and associated complications. (Not by a huge margin, but the risk is still significant.)
Having 3 normal embryos gives you a 95% chance of becoming pregnant.
IVF Success Rates Under 35
The Society for Reproductive Technology (SART) states that for women under 35, the percentage of live births via IVF is 55.6%. Live births per first embryo transfer is 41.4%. With a later embryo transfer, the live births percentage is around 47%.
Transferring more than one embryo at a time increases pregnancy rates, but it also increases the chances of multiple implantations leading to twins, triplets, etc.
While there are couples who come in, are diagnosed, and get pregnant via IVF in the first round – they are an anomaly. Most couples have to undergo that previously mentioned three IVF rounds or more.
The first IVF cycle will often be successful at a high quality program. Unfortunately, many couples will not have successful first cycle IVF results and will need to consider a second cycle.
It's a complicated process. However, sometimes a fertilized egg doesn't make it to implantation. For every 10 fertilized eggs, between 4 and 6 won't make it to implantation (9,10).
In rare cases, two eggs can be fertilized at different times during two or more acts of sexual intercourse, resulting in fraternal twins with two different fathers, called bipaternization. Monozygotic, or identical twins, occur when one fertilized egg splits into two separate embryos.
A single embryo transfer during IVF is the standard of care for the majority of people trying to conceive. The CDC, American Society for Reproductive Medicine, and the Society for Assisted Reproductive Technology all recommend one embryo transfers for most IVF patients. Why is that?
Between one-third and one-half of all fertilized eggs never fully implant. A pregnancy is considered to be established only after implantation is complete. Source: American College of Obstetricans and Gynecologists.
During IVF, multiple eggs are harvested and fertilized. This often leads to multiple viable embryos, one or more of which may be transferred to the uterus. Our team explains single versus multiple embryo transfer at the Fertility Center of San Antonio in San Antonio, TX.
On average, only 30 to 50 percent of embryos make it to the blastocyst stage. The failure of some embryos to not make it to the blastocyst stage is most likely due to a defect in the embryo. If, for example, we have 10 embryos on day 3 and we select two to transfer on day 3, we may not select the right embryos.
In humans, a fertilized egg is no guarantee of reproductive success. Most embryos stop developing and perish within days of fertilization, usually because they have an abnormal number of chromosomes.