The goal of IVF
Infertility affects 1 in 10 women and men. For a natural, successful pregnancy, the ovaries release an egg fertilized by one sperm in the fallopian tubes. The newly formed embryo travels and attaches to the uterus to continue the pregnancy. With infertility, there may be insufficient eggs, low-quality sperm, damaged fallopian tubes, or a combination of these issues. In vitro fertilization extracts the eggs and sperm to create the embryo in a cell-culture dish and implant the embryo. This can happen in one or more cycles until a successful pregnancy occurs.
Starting IVF: Consultation, medication, and anticipation
Any person or couple starting IVF would have received tests to confirm fertility issues. From there, further support happens, like genetic counseling. The doctors involved will inform the patients of the entire process from start to end. The clinic will need as many female gametes, or eggs, as possible. The woman will start on hormone medication to encourage more egg production. A follow-up trigger shot will help release the eggs a few days before retrieval.
Day zero: All about extraction and fertilization
Once the woman starts to produce the eggs, the doctor will extract as many eggs as possible. Known as the egg retrieval process, the doctor will use needles to access the ovarian follicles. The needle will suction up each gamete, which the doctor will store in a special container. The doctor will then pass the eggs over to the embryologist of the fertility clinic. The embryologist will combine the eggs with the appropriate sperm sample right away. The fertilization happens organically in the culture dish or with intracytoplasmic sperm injection (ICSI). The cells are stored in an incubator for the embryologist to check the next day.
Day 1-3: Creating the embryo
On day 1, about 24 hours later, the embryologist checks to determine if any of the embryos fertilized. The embryo looks like a single cell with 2 inner circles called the nuclei. Close to 80% of the available eggs will be successfully fertilized. The embryologist will continue to monitor the embryos under a microscope. By day 2, the embryo should have 2 or 4 clear cells. By the third day, the embryo should have 8 cells. At this point, the embryos are ready for transfer into the uterus.
Blastocyst culture: The 2-day advantage
A doctor will insert the 3-day embryo into the uterus. From there, the embryo takes 2 additional days to turn into a blastocyst. In other words, a blastocyst is a 5-day embryo. Some clinics decide to wait 2 extra days before implanting the embryo, creating a blastocyst culture. The doctor implants the best blastocyst culture, and the rest are frozen for future use. The woman is then monitored for pregnancy, ending the IVF cycle. If unsuccessful, the clinic will try additional cycles until success.
Are there advantages to blastocyst cultures?
Between day 3 and day 5, an embryo may degrade due to multiple reasons. These embryos will result in a failed pregnancy, and the clinic will need to start another cycle. The embryos can die either in the womb or at the lab. In the womb, the clinic will be unable to determine which will survive past day 3. As a result, some clinics will implant multiple 3-day embryos. This can result in multiple pregnancies. With a blastocyst culture, the clinic can choose the best single embryo. The extra time may improve the chances of pregnancy.
Get the most out of IVF
A blastocyst culture is a slightly mature embryo. Both 3-day and 5-day embryos have a chance of pregnancy. However, some clinics prefer to go with 3-day embryos. Single blastocyst cultures may not be as effective in older women. Speak with the doctor and IVF clinic about blastocyst cultures. Clinics
advise the best method available.