In vitro fertilization or IVF, effectively treats many causes of male and female infertility. IVF can be an excellent option for many patients who have struggled to get pregnant with other fertility treatments. It is an especially successful treatment for women with tubal issues, endometriosis, or polycystic ovarian syndrome. For women of advancing maternal age, IVF is also very successful with the use of donor eggs. Men with low sperm counts and couples with inherited diseases also benefit from IVF.
IVF has been around since the mid-1980s to treat couples experiencing infertility. Back then, the chances of bringing home a baby after IVF was a dismal 10%, less than what you would expect from Mother Nature at about 20%. Today, over 190,000 IVF cycles are conducted in the U.S., with average live birth rates of over 32% for women of all ages. Younger women with younger eggs have even better success, with live birth rates approaching 50%.
What has accounted for this incredible increase in success with IVF? Most notably are the new techniques that have arisen over the last several years that offer the possibility of improving a patient’s odds of having a baby through IVF. Let’s take a look at some of these success-boosting techniques.
Assisted Hatching
Sometimes viable embryos do not implant in the uterine wall simply because they are unable to break free from their surrounding “jelly coat,” called the zona pellucida. We perform assisted hatching in the lab right before embryo transfer using a laser to create a hole in the zona. This allows the embryo to “hatch” and make contact with the lining of the uterus and implant.
Intracytoplasmic Sperm Injection
We first used ICSI, or intracytoplasmic sperm injection, to treat cases of severe male factor infertility. In this technique, a single sperm is injected into the cytoplasm (interior) of the egg. Today, the use of ICSI is now routinely applied to a wide range of clinical situations whenever there is a possibility that fertilization may not occur. Such situations may include unexplained infertility or when frozen sperm samples survive their thaw poorly. Further, ICSI is used in any case where there is an extreme need to maximize normal fertilization, such as when a woman has only a few eggs retrieved.
“Freeze All Embryos” IVF Cycle
In the past, we preferred to perform fresh embryo transfers for most patients because the embryos had a better chance of implanting and developing into a baby than frozen embryos did. However, over the past several years, vitrification techniques for freezing and thawing embryos have improved so much that frozen embryos now have an equal or perhaps better chance of implanting than fresh embryos.
When there is a planned “freeze all embryos” IVF cycle, the developing embryos are frozen via vitrification and stored until they are transferred at a later time. This technique is especially beneficial for women at risk of hyper ovarian stimulation caused by the medications used to produce multiple eggs during the cycle. We have found that high hormone levels associated with ovarian stimulation might affect the lining of the uterus, making it less likely for the transferred embryos to implant. We see this particularly in patients who develop higher progesterone levels earlier in the ovarian stimulation cycle.
Preimplantation Genetic Screening (PGS)
PGS helps us answer the question of which embryos have the greatest potential to become a healthy pregnancy and baby. Humans have 23 pairs of chromosomes, inheriting one copy of each chromosome from either parent. When sperm fertilizes an egg, it creates an embryo which should consist of 23 chromosomes from the mother and 23 chromosomes from the father. But often, embryos are created with too many or too few chromosomes. This is a major cause of miscarriage and increases dramatically with maternal age. One of the most common examples is Down Syndrome, or Trisomy 21, which is caused by the presence of a third copy of chromosome 21.
PGS gives the patient two advantages. First, it allows us to be 99% certain the embryo has the correct number of chromosomes thereby increasing the chance for a healthy pregnancy. Second, it allows the patient to transfer only ONE embryo thereby decreasing the chance of twins (which have a much higher rate of complications). The pregnancy rate of transferring just one embryo that has undergone PGS and is deemed chromosomally normal is the same as transferring two embryos that are not tested.
