The sex hormone estradiol plays a prominent role in the success of in vitro fertilization (IVF). Elevated estradiol levels produce lower IVF success rates and greater hurdles to pregnancy. Normal estradiol levels mean better IVF success if all other influencing factors are normal and healthy.
Estradiol, also often referred to as E2 or 17Β-estradiol, is a form of estrogen secreted by the ovaries. The levels of estradiol in the body has a significant impact on fertility by controlling follicle stimulating hormone (FSH) levels, egg reserve, egg quality, and sometimes the efficacy of traditional ovulation stimulating drugs used to boost fertility. To determine the estradiol level, a blood test called the estradiol test is run on the third day of menstruation.
In vitro fertilization (IVF) is an assisted reproductive treatment where eggs are harvested from the ovaries, fertilized with donor sperm in culture medium outside the body, allowed to mature for several days, and then re-implanted in the uterus. The success of IVF depends on having a good egg reserve and a strong response to ovulation stimulating drugs. Since estradiol levels directly impact egg reserve and the efficacy of ovulation stimulating drugs, it is clear that estradiol and IVF success are directly connected.
Problems with estradiol and IVF occur when the estradiol level is high. If this is the case, egg reserve is typically low and ovulation stimulating drugs will probably not promote the multiple egg release needed for IVF harvesting. To overcome the issues of high estradiol and IVF failure, the lupron flare protocol may be tried. This method uses carefully timed lupron shots and follicle stimulating hormone to increase the number of eggs ripened during an IVF egg harvesting cycle.
Elevated estradiol and IVF failure can also be caused by poor egg quality, eggs that are unable to be fertilized, or eggs that don't develop once fertilized. The use of donor eggs or assisted hatching can overcome these issues. Donor eggs for IVF, much like donor sperm, can come from family members, friends, or from an anonymous donor through an egg donor clinic. Once the eggs are selected, they pass through the IVF procedure and are implanted in the woman. Assisted hatching is a procedure used to make a small hole with a slightly acidic solution in the outer shell of the egg, called the zona pellucida, which increases the chances that sperm can penetrate the egg.
IVF is a complicated procedure with typical success rates between 10% and 40%. A healthy level of estradiol is important for IVF success, but it is only one piece of a very complicated process. Success of IVF also depends on the levels of other sex hormones, the general health of the woman and her reproductive structures, her age, and the number of eggs implanted.