A couple will often choose to have in-vitro fertilization (IVF) after less-invasive and less-expensive methods have failed. Understanding IVF success rates hinges largely on comprehending the effects of egg donor age and the number of fertilized eggs transplanted into the uterus, as well as the number of eggs that are harvested and fertilized.
Egg Donor Age
As a woman ages, her eggs become less and less viable. For example, a 32 year old woman attempting an IVF cycle with 1-2 fertilized eggs has a 16% chance of conceiving and having a live birth. In the same situation, a 41 year old woman has only a 7% chance of delivering a live birth. For this reason, some women who are over 40 might decide to use donor eggs from a younger woman. Egg banks or accepting eggs from a close friend or family member are popular options for procuring younger eggs.
The Number of Eggs Transplanted
For some couples, transferring only 1-2 fertilized eggs per cycle is their choice. Not only does this method give each fertilized egg a better chance of survival, it also limits the chance of a higher-order multiple pregnancy. For other fertility specialists and couples, transplanting 4-5 fertilized eggs is the norm. While this does increase the likelihood of a multiple birth, it also carries a higher success rate overall. The woman's pelvic size, attitude concerning multiples, and health are all factors when considering how many fertilized eggs to transplant into the uterus for an IVF cycle. While some fertility specialists are not comfortable with intentional multiple pregnancies, others feel that twins or triplets are completely safe for a healthy mother.
The Number of Eggs Harvested and Fertilized
Even if a couple is doing low-count transfers, they can increase their chances of conception and live birth by doing multiple cycles. This is where the number of eggs harvested and fertilized comes into play. For example, a 37 year old couple who has attempted with only 1-2 eggs in one cycle has a 14% chance of success. However, the same couple has a 50% chance after the tenth fertilized egg. Whether this was done in two or ten cycles is inconsequential. It is the number of eggs transferred that results in the higher success rate.
When considering IVF success rates, it's important to consider the age of the egg donor, the number of eggs fertilized, and the number of fertilized eggs transplanted per cycle.
James Copper is a writer for http://www.ivfplus.com where you can find out about ivf success rates and how it can help you get pregnant
