I wanted to share an article from a Canadian news source what some might find as common knowledge but, for others, this is new information. If you are just starting out on your research for information on Assisted Reproductive Technology, stay tuned as I will be blogging about several educational issues involving ART.
Your comments and shared experiences are welcomed!
In-vitro fertilization, the most common ART procedure, is used to overcome a variety of fertility difficulties, particularly tubal problems and sperm deficiencies.
During IVF, medications are often used to help stimulate the development and release of a woman’s eggs. The eggs and sperm are then collected and placed together in a laboratory dish to fertilize. If the eggs are successfully fertilized, embryos are then formed and start to divide and develop. Once those embryos reach a certain stage in their development, they are then transferred into a woman’s uterus. Hopefully, one of the fertilized eggs will implant and develop just as in unassisted conception.
Stage 1: Ovarian stimulation, monitoring, and ovulation triggering
The goal of the first stage is to create a large number of mature follicles to increase the chances of fertilization. Since a woman’s body normally releases one mature egg every month, a medication called a follicle stimulating hormone (FSH) can be used to stimulate the ovaries to develop more follicles. Follicles are fluid-filled sacs in which eggs mature. Each follicle holds one egg. At the beginning of the cycle, each follicle is approximately 1 mm to 2 mm in diameter.
During this stage, you may also be prescribed other medications used to block, supplement, or even augment your body’s natural hormonal cycle. Treatments are individualized and vary significantly. Your fertility specialist is the best person to talk to for more information.
During this stage, your fertility specialist may use ultrasound to monitor the number and size of maturing follicles in your ovaries. Blood tests may also be used to monitor hormone levels, which will help determine the best time to administer medication and to retrieve the eggs. Below is a diagram outlining one possible treatment protocol. Please remember that there are many different protocol options, so don’t be concerned if you are doing something different. Your fertility specialist will pick the best protocol for you. See Figure 1 below.
Stage 2: Egg retrieval
In the second stage, another medication called a human choriogonadotropin is used to stimulate the release of mature eggs. Your fertility specialist will identify the mature follicles using ultrasound, and then, with a needle, withdraw as many eggs as possible from both ovaries. At this point, each follicle is approximately 16 mm to 20 mm in diameter. Figure 2 outlines this process, showing how the eggs are retrieved from their follicles
Stage 3: Fertilization
About two hours before the eggs are retrieved, a semen sample is collected, usually from the male partner unless you are using donor sperm. Approximately 50,000 sperm are placed with each egg in the incubator where they will hopefully form an embryo. When only a few sperm are available, intracytoplasmic sperm injection (ICSI) may be attempted. In this procedure, a single sperm is injected into an egg to facilitate fertilization. ICSI is outlined in more detail in the following section.
The next day, called “Day 1” in the lab, the eggs will be examined under a microscope to determine whether fertilization has occurred. If it has, the embryos will be ready to transfer into the uterus within 2 to 4 days of “Day 1.” Figure 3 outlines the fertilization steps.
Stage 4: Embryo transfer
The embryos are placed in a tube and transferred back into the uterus. The procedure is usually painless, though some women may experience some cramping. The number of embryos transferred depends on a woman’s age, cause of infertility, pregnancy history, embryo quality, and other factors. Most fertility clinics will transfer two or three at most, since transferring more embryos can increase the risk of multiple pregnancies (twins or triplets). Your fertility specialist would decide the appropriate number of embryos to transfer for you. Figure 4 in the photo below outlines the embryo transfer steps. The uterine lining is prepared for implantation, often by supplementing with progesterone medication.