IVF Success Rates
Learn About IVF Success Rates at Houston Fertility Specialists
We define success and the birth of a healthy baby following an uncomplicated pregnancy. Historically in IVF embryo implantation rates (the chance that an embryo transferred to the uterus would attach and grow) were low. This was because we could not identify which embryos were normal, healthy, and could result in a pregnancy. In addition, we could not optimize the ability of the uterus to receive an embryo (endometrial receptivity). To overcome these limitations, multiple embryos were transferred in the hope that at least one would attach. This resulted in low pregnancy rates with a high chance of multiple pregnancy.
“We biopsy and test each blastocyst for chromosome number, so that we can avoid transferring embryos which cannot result in a successful pregnancy.”
Culture of embryos to the blastocyst stage allows embryos to self-select for quality. We know that embryos which do not reach blastocyst will not implant. We biopsy and test each blastocyst for chromosome number, so that we can avoid transferring embryos which cannot result in a successful pregnancy. Endometrium is less receptive in the cycle of ovarian stimulation than in a subsequent cycle where its development can be controlled. This means that we freeze all embryos for later transfer and improve implantation.
The best way to maximize the chance of a successful pregnancy is to transfer a single good-quality chromosomally normal embryo at a time. This is termed Euploid, an embryo with a normal complement of chromosomes. eSET, or elective single embryo transfer. This both increases the implantation rate, but also minimizes the chance of miscarriage and multiple pregnancy. Most miscarriages occur because the embryo which implanted was not normal. By not transferring a euploid, chromosomally abnormal, embryos, we can reduce the miscarriage rate from 25-30% to less than 10%.
Transfer of more than one embryo slightly increases the chance of pregnancy, but significantly increases the multiple pregnancy rate with related complications: increased rates of miscarriage, maternal medical problems including high blood pressure, diabetes, toxemia, and doubles the chance of death. The main risk to the babies relates to the increased prematurity rate which significantly raises the chance of long-term hospital stay, cerebral palsy, long-term disability, and increases the death rate 5-fold.
The chance of creating a euploid embryo depends on the age of the woman, the number of eggs produced, and sperm function. For example, women under age 35 with 10 or more eggs has a greater than 90% chance of having one or more euploid embryos while a woman over 42 with 5 or fewer eggs has less than a 10% chance of having a euploid embryo. Age does not affect the likelihood of implantation with transfer of a euploid embryo. Since employing Euploid eSET in 2013, the pregnancy rate has been 60% and the miscarriage rate 8%, independent of maternal age.