Gestational Surrogacy

Since gestational surrogacy relies upon undergoing IVF, we suggest you consult our detailed course on the subject, and the important decisions you’ll face.

If you intend to use donor eggs in conjunction with surrogacy, you may want to review our IVF with Donor Eggs course and a specific lesson on tailoring IVF for cycles using donor eggs.

As for tailoring the cycle for considerations related to surrogacy, there may be a few subjects to consider. It’s important that you discuss any medical decision with your doctor at length and with data they think is most relevant to your circumstances.

During IVF, once a laboratory fertilizes the retrieved eggs, they have the decision to grow embryos to the “cleavage” stage (often reached on “Day 3”) or the “blastocyst” stage (often reached on “Day 5” or “Day 6”) before trying a transfer.

Embryos that have survived to the blastocyst stage are more likely to lead to a live birth, as you can see below. Unless the intended parents have issues making embryos that can reach blastocyst, or a clinic’s not confident in its abilities to grow blastocysts, allowing embryos to grow to this stage may be preferable. To learn more about the importance of the laboratory and how to gauge its abilities, see our course here.

For one, using a blastocyst stage embryo improves the odds the doctor selects an embryo that will lead to a successful transfer. Second, it preserves the ability to have the embryo tested (which we’ll cover next), and finally if embryos need to be frozen for a later date (this flexibility can be invaluable when trying to line up a gestational carrier), they’re more likely to survive the process as heartier blastocysts, as you can see from multiple studies below. To learn more, you can see our dedicated lesson here.

If embryos are grown to the blastocyst stage, they can be biopsied (where a few cells are removed and tested) to ascertain if an embryo has the right number of chromosomes. In effect, this testing is a tool to help doctors select embryos for transfer that are more likely to lead to a delivery.

Such testing, known as Preimplantation Genetic Testing for Aneuploidy (PGT-A) should be done on blastocysts rather than cleavage stage embryos because the biopsy is less likely to have a negative effect, as you can see below.

Credible experts disagree on when PGT-A is most useful and below we provide a catalogue of the trade-offs.

In the case of an IVF cycle using a gestational carrier, PGT-A is likely more warranted given the cost and effort spent to line up the process and the seemingly larger risk (e.g. a carrier will stop the process) should the first few transfers not result in a delivery.

A secondary byproduct of using PGT-A to test embryos is that doctors, intended parents, and gestational carriers likely have more faith in each embryo that passes PGT-A and are more open to transferring one embryo at a time, as you can see below in the evidence from a single center. To learn more about PGT-A, the process and the trade-offs, see our lesson here.