The chances of an individual couple of having a baby following one completed cycle of IVF treatment depends on two main factors.
Firstly, the overall success rate of the treatment clinic (centre) and secondly the characteristics of the couple seeking treatment.
The overall live birth rate per treatment cycle has been rising steadily by approximately 1% per year globally. Each age group has experienced significant increase in success rates.
The overall success rate per IVF treatment cycle could range from 10% to 50% depending on many factors.
1. Skills and Experience: skills and experience of the team including doctors, nurses and embryologists.
Even in the same clinic with the same clinical protocol, IVF outcome varies between difference in success rate between large and small clinic. Variation in embryo transfer technique can affect the result of the treatment.
2. Type of Ovarian Stimulation protocol: The natural cycle or clomiphene stimulated IVF have poor success rate per treatment cycle compared to gonadotrophin-releasing hormone (GnRh) agonist and GnRh agonist in addition to gonadotrophin for ovarian stimulation result in higher pregnancy and live birth rate than using gonadotrophin alone.
3. Assisted Hatching and Blast cyst Transfer: There is some evidence that assisted hatching in selected group of patients, result in improvement of pregnancy and live rates.
Similarly there is evidence that blast cyst transfer results in improvement in pregnancy and live birth rates with lower incidence of multiple pregnancy rates.
4. Age of the Woman: The age of the woman has a significant effect on her fertility and the live birth rate decreases significantly from the age 35 years when the woman is using her own eggs.
The older the woman, the higher the chance of cancellation, the lower the chance of success and the higher the chance of miscarriage and chromosomal abnormalities.
The live birth rate of woman aged 40 years and above using their own egg without donor egg is about 10% per cycle initiated.
Approximately 10% of all IVF cycles are cancelled before egg collection. The main reasons for cancellation are no or poor egg production (83%), patient personal reasons (10%), excessive response or hyper stimulation 5%.
5. Use of Donated Eggs, Embryo and Sperms: The highest live birth rates are found among women who have had IVF with donated eggs, donor sperm or donated embryos. The overall delivery rate per transfer following use of donor eggs nearly 50% compared to 35% following use of own egg.
6. Numbers of Embryo Transferred: There is evidence that the success rate increase with the number of embryos transferred up to a maximum of 4 embryos. There is also an increase in multiple pregnancies with its attendant risks of premature babies and increased incubator use. In the UK, a maximum of 3 embryos may be replaced for women age 40 years and above, but 2 embryo for those who are 39 years and younger. The aim in the UK is to reduce the risk of multiple pregnancies.
7. Duration of Infertility: The longer a couple has been infertile, the lower the chances of success. This might not be unconnected with the age of the woman.
8. Cause of Infertility: The outcome of IVF treatment varies with the cause of infertility. Tubal cause is better than cause from endometriosis, unexplained and male factor infertility.
9. Number of Previous IVF Treatment Cycles: The live birth rate is highest in the first cycle and drops by the 5th cycle. Cycle 6th to 8th appears to give a reasonable chance of success, but few patients persevere that long.
10. Previous Pregnancy and live Birth: Women who have been pregnant before or have had a previous IVF birth have a higher chance of success than women who have never been pregnant.
