IVF Procedure - A Brief Summary

In vitro fertilization (IVF) is a procedure in which eggs (ova) from a woman’s ovary are removed and sperms are mixed with these eggs in a dish. They are then kept for incubation where the sperm fertilizes the egg naturally. The fertilized egg (embryo) is returned to the uterus after 3 or 5 days of culture.

1. Ovarian Stimulation and Egg Retrieval

Fertility drugs will be needed to stimulate the ovaries to develop several mature eggs. When the leading egg reaches 18 mm or more, they are ready for collection. HCG/GnRH agonist is administered at this stage for maturation. Egg retrieval is done after 35 hours. Ultrasound is used to guide a hollow needle directly into each follicle. The liquid which surrounds each egg is then sucked out and placed in a tube and given to embryologists for screening of the oocytes.

2. Screening of the Oocytes

The ovary fluid is poured into a dish and observed under a microscope. The oocyte with surrounding cumulus cells called the OCC complex is picked by the embryologist and transferred into another dish containing media. This dish is then kept for incubation for 2-3 hours.

3. Sperm collection and processing in the lab

Semen samples should be collected from the male partner and processed by different processing techniques (DG/Swim-up) depending on the quality of the semen sample. The processed semen sample is checked for count and motility to determine the selection of procedure (IVF/ICSI). IVF can be done when the quality of the semen sample is good. ICSI is recommended for a poor quality semen sample.

4. Fertilization

> 1-3 oocytes are kept in culture media droplet under oil, pre-equilibrated overnight

> After 3-4 hours of oocyte incubation, 10-20µL of washed suspension of motile spermatozoa is added.

> The concentration of the motile sperms to the oocytes is checked

> The insemination dish containing the oocytes and washed sperms are kept in a CO2 incubator immediately to avoid any pH change.

> After 24 hours (Day 1), the incubated oocytes are denuded to check the fertilization. Fertilized embryos are kept in fresh media for further growth

> After 48 hours (Day 2), the status of the embryos is checked to monitor the development of the embryos. Commonly at this stage, the embryos have 2-4 cells(blastomere)

> After 72 hours (Day 3), the embryos are in the 8 to 10 cell stage. Most commonly, embryos are placed in the uterus at this stage. Alternatively, fertilized embryos can be frozen in liquid nitrogen by using vitrification methods. These frozen embryos can be thawed and transferred at any time later.

> In the case of blastocyst transfer, the embryos are maintained in the lab for five or six days and transferred into the uterus.