We should consider that, go get pregnant the “conventional” way, our body should perform a lot of things and all these things should happen at the same time.
Let’s remember what must happen:
The women should be in her fertile period, near ovulation.
The ovary must respond to the brain command to ovulate: the ovary will take several folicules out, where the eggs are kept but, ONLY ONE WILL SUCCEED IN OVULATING (except some rare cases of multiple ovulation).
The tube must “catch” the egg just as a baseball glove would catch the ball.
While all this happens in the womans body, sexual intercourse should happen to so the sperm will be able to enter the uterus through the cervix, swim up and reach the tube.
Fertilization of the egg with the sperm happens in the external part of the tube where they should find each other so the tube will after be able to push the formed embryo inside the uterus where, the endometrium should be in perfecte conditions to receive it and, if all this happens, the embryo will stick there and stay during nine months.
As mentioned, lot of things should happen at the same time to get pregnant. Considering also that the egg lives only during 24 hours and, if not fertilized it will die. Sperm live up to 3 days, that is why near (days before and after) the fertile days it is recommended to keep sexual intercourse.
Every time we try, we have 12-15% possibilities. It is normal that 90% of couples that are planning a pregnancy with no apparent infertility will succedd in the first year of trying. Some will, of course, suceed in the first months.
Now, when an IVF cycle is performed, the same happens, just having sexual intercourse once but, we increase the possibilities from 40 to 70% with the ovaries stimulation: instead of only growing one folicule, it will grow ALL the ovary has available for that month. Then, the eggs are extracted, observed in the lab and fertilized. With all this, we have all the information about how many eggs were produced in the cycle, their quality, how they fertilized and how the embryos develop.
According to the morphology of the embryo, the best ones will be transferred inside the uterus to achieve the pregnancy.
It is important to say that, placing the embryo inside the uterus does not mean that there is a pregnancy. One should wait the recommended time to do the blood test.
It can be that, the pregnancy will not happen during the first cycle of pregnancy, just as will not happen naturally. It is true that, when trying more cycles we increase the possibilities, even though the % per try will be the same.
It is important to consider that after several failed cycles, it is recommended to study more factors like endometrium (when the embryo cannot stay there), any anomaly with the embryos or any other factor to consider according to the specialist.
So, having sexual intercourse naturally only one egg is produced but, when having a treatment of low complexity like AI more than 2 eggs are produced, increasing the possibility to the couples that cannot get pregnant the natural way.
With and IVF also the eggs produces is increased but, also 2 or 3 selected formed embryos will be transferred, increasing then the possibility of pregnancy in patients that didn’t succeed naturally or with some cycles of AI.
It is then very important to: trust your infertility clinic, your doctor, clarify all your doubts and follos all the indications.
Fdo. Dra. Sonia Fuster. Especialista en infertilidad. Centro FiVER