FIVE PIECES THAT CAN HELP SOLVE THE IVF REPRODUCTIVE PUZZLE

For a procedure that can feel miraculous to parents struggling with infertility, in vitro fertilization is technically rather simple. Dr. Cliff Librach, chair of the reproductive biology section of the Ontario Medical Association, explains how it works.

1. Stimulating egg production

Women normally produce one egg each month. But in order to increase the chances of creating a viable embryo, women undergoing IVF receive injections of hormones called gonadotropins, which stimulate the ovaries into producing multiple eggs. The number of eggs is determined by the woman’s age and what’s known as her “egg reserve.” According to Dr. Librach, younger women can produce upwards of 20 eggs, while older women usually produce less than 10.

2. Collecting the eggs

Once the eggs are mature enough to be harvested, they are extracted through a procedure called transvaginal ultrasound-guided needle aspiration, says Librach. The process involves sucking up the clutch of eggs through a tiny tube inserted inside the woman’s vagina. Women are usually sedated or placed under anesthetic for the procedure, which takes place around the time of their cycle that they would normally ovulate.

3. Fertilization

The eggs are then combined with sperm in a Petri dish and incubated. “Usually, we try to have fresh sperm,” says Librach, adding that this means the male donor has to be standing by to produce a sample. If a sperm bank is being used, however, then the sperm arrives frozen. The sperm and eggs can simply be mixed together, but if the father has a low sperm count, the sperm is inserted directly into the egg through a process called intracytoplasmic injection.

4. Selecting an embryo

It only takes between three and six days to produce a viable embryo in the lab. Previously, doctors selected the healthiest one based on its shape, but more sophisticated methods like genetic testing have since been developed. Other techniques include observing time-lapse videos of the embryos growing. “It’s really cool,” says Librach. Embryos that aren’t initially chosen can be frozen indefinitely for future use. If the woman discontinues IVF treatment, unused embryos can be discarded or donated either for research or to help another woman become pregnant.

5. Implantation

As selection techniques have improved, it’s become normal for doctors to only implant one embryo back into the uterus. But in cases where chances of pregnancy are low, more than one can be inserted. “The upside is more chance of pregnancy, but the downside is more chance of a multiple pregnancy, which we want to avoid,” says Librach. “That’s a higher risk to mom and the babies.” If IVF results in a woman becoming pregnant with more than two babies, the number of embryos can be “selectively reduced.” — Ben Spurr