fiv-fecundacion-in-vitro In vitro fertilization involves producing an embryo outside the body. This procedure includes a series of steps which are essential to ensure the possibility of a pregnancy. The steps are as follows:

1. Ovarian stimulation. This is necessary to obtain an ideal number of follicles with mature eggs. In a natural cycle, a certain number of follicles are recruited in the ovary each month. Of these, only one is selected to become an egg. The rest die. This selection is controlled and regulated by FSH (follicle stimulating hormone). If FSH plasma levels are kept high, it is possible for almost all the recruited follicles to become ovulatory. What are the benefits of this? The more follicles there are, the more eggs there are, and therefore, the more embryos, making it possible to select those of the highest quality for transfer. Therefore, ovarian stimulation with FSH will be personalized based on your age and ovarian reserve. It will be regularly monitored by means of ultrasounds in order to prevent hyperstimulation. We will also use other drugs, including GnRH agonists and/or antagonists (to protect you from untimely ovulation) and LH, if necessary. As the follicles grow, we will decrease the amount of FSH. When they reach 20 mm, if estradiol levels are within normal limits, ovulation is triggered using hCG. The eggs are collected 34-36 hours later. We recommend resting for 24 hours after the puncture. 

2. Egg collection. Follicle punctures and egg collection are done vaginally under sedation. The procedure is monitored by ultrasound with an anaesthetist present. The liquid obtained from the puncture is sent to the laboratory, where it is examined for eggs.

3. Egg fertilization. Once selected, the mature eggs (metaphase II, MII) are placed in a petri dish with a suitable culture medium. A specific number of sperm are then added. If fertilization is done by microinjection (ICSI), only one sperm is used. 24 hours later, we look under a microscope for signs of fertilization (two pronuclei). In 70-80% of cases, the sperm fertilize the eggs, producing embryos.

4. In vitro development of the embryos. The embryos are observed daily to see how they divide and note characteristics such as cell normality, quality and number, which determine the grade of embryo quality. During this entire time, the embryos are kept in special incubators until they are transferred. This may be two, three or five days after the puncture. Today, it is possible to monitor embryo development in real time (time-lapse) without having to remove them from the incubator.

5. Transfer. Before the embryos are transferred to the uterine cavity, the doctors will inform you of the number of embryos available and their quality. You will be asked if you want to cryopreserve any of them. The decision is yours. The Assisted Reproduction Act limits the number of embryos to be transferred to three. In order to reduce the number of multiple pregnancies, at FIVMadrid, for women under the age of 35, we recommend transferring a single embryo, but only when conditions are favourable and the pregnancy rate is not compromised. For women over the age of 38, two embryos are usually transferred, three in very exceptional cases. Embryo transfer is a simple procedure which does not require sedation. It is done with a full bladder and monitored by ultrasound to control the release of embryos in the uterine cavity. We recommend limited activity for two or three days after the transfer. The woman should also take progesterone to help embryo implantation. After two weeks, you will need to take a pregnancy test and contact the clinic with the results. Good luck! If you become pregnant, your pregnancy can be considered a normal pregnancy. It is advisable to notify your obstetrician that you conceived using IVF.


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