There are two forms of surrogacy. The first is “gestational surrogacy” which is also known as “IVF surrogacy”. In this case, eggs are retrieved, fertilized, and the resultant embryo is placed into the uterus of a third person. Once a pregnancy is confirmed, the “gestational carrier” is discharged to regular obstetrical care and carries the pregnancy. This course will focus on this form of surrogacy.
This contrasts to ”traditional surrogacy” where the same person who provides eggs also gestates the pregnancy. This form of surrogacy is incredibly rare and won’t be our focus. It’s common for friends, family, and strangers to confuse the two.
Generally speaking, IVF with gestational surrogacy tends to be relatively successful. Let’s look at national data from the United States where you can see gestational surrogacy coincides with higher rates of embryo implantation, pregnancy, and live births on a per-transfer basis.
These relatively-high rates of success tend to be a global phenomenon, and as an example, you can see in national data from India presented below.
As for risks, investigators concluded from a larger meta-analysis from three American studies and one each from Canada and Finland that rates of hypertensive disorder and planetal issues were no different in gestational surrogacy compared with all IVF patients. Investigators noted the risk of premature delivery (<37 weeks) were similar between groups, once one adjusted for the disparity in singleton versus multiple births. The odds of lower birth weight babies were decreased amongst surrogacy deliveries, again, when one compares singletons versus multiples.
As you’ll see in a later lesson, a large number of gestational surrogacies involve the use of donor eggs (see our detailed course here). When we look at birth rates only amongst those using donor eggs, gestational surrogacy still compares favorably.
Moreover, the odds of preterm delivery and low birth weight offspring remains lower once we correct for the number of babies being carried.
As you’ll see in the next lesson, there’s a wide variety of intended parents who benefit from gestational surrogacy. Some have the option of trying to carry, in which case gestational surrogacy may stack up favorably. Many others don’t have the option to carry, in which case, it can be difficult to “compare” or place into context success rates for gestational surrogacy.
Eight studies, mostly emanating from the U.K., the U.S. and Brazil, when analyzed together, reflected no major challenges faced by the offspring of surrogacy.
Another 16 studies, mainly originating from the U.K. and run by most of the same investigators from the studies above, looked at the longer-term impact to intended parents. Aside from one interval at child age year two, “the mothers and fathers of children born through surrogacy had similar marital satisfaction as parents in gamete donation families.” Ultimately, investigators who summed up all 16 studies came to a similar conclusion.