Understanding IVF Embryo Development

Did you know your surrogate is already “pregnant” before an embryo transfer even happens? It can be hard to comprehend, but that it is the reality of IVF pregnancies.

In a traditional pregnancy, gestational age is determined based on the day of ovulation. Fertilization and implantation of the embryo typically occurs about two weeks later. In the case of IVF, and specifically gestational surrogacy, pregnancy works a bit differently. The eggs that will eventually become embryos are not allowed to travel from the ovary into the uterus to await fertilization. Instead, the eggs are retrieved, either from an intended mother or egg donor, directly from the ovary before they are released. This happens two weeks into a woman’s typical 28-day menstrual cycle.

Growth & Evaluation

Those eggs are then fertilized outside of the body and allowed to begin growing. A reproductive endocrinologist closely monitors the cell multiplication over the next several days. In the case of a planned fresh embryo transfer, the eggs will then be transferred into an awaiting uterus on either day 3, 5, or 6 of external development. In the case of a planned frozen embryo transfer, the embryos are typically frozen, thawed and transferred on day 5 of development.

In the meantime, the recipient of the embryo will be on a hormone therapy regimen that will cause their body to mirror where it would be in a non medicated cycle. This process allows doctors to create the ideal environment for the embryos to implant and grow before moving forward with the transfer.

Embryo Transfer

With this in mind, the embryo recipient walks into the fertility clinic on transfer day 2 weeks “pregnant” before the transfer even occurs. During the transfer, the doctor will migrate the embryo or embryos into the awaiting uterus, and at the conclusion of the transfer, the recipient is said to be 2 weeks plus the age of the embryo pregnant. If a 5-day blastocyst was transferred, the recipient will walk out of the clinic 2 weeks and 5 days pregnant.

The term “pregnant” is relative to whether the embryos actually implant and continue to develop. A pregnancy test, which will consist of a blood test, will generally be done 10-12 days after the embryo transfer. If the result of the pregnancy test is positive, your surrogate will be somewhere between 4 weeks 3 days-5 weeks pregnant. Around the 10 week mark, your surrogate will be released to the care of an obstetrician and the pregnancy will follow the course of a traditional pregnancy.

Learn about a baby’s growth (or the growth of twins), week by week!

Kim Bergman, PhD, a licensed psychologist of 26 years, has specialized in the area of gay and lesbian parenting, parenting by choice and third party assisted reproduction for over two decades. Dr. Bergman has created a comprehensive psychological screening, support and monitoring process for intended parents, surrogates and donors. She is the co-owner of Growing Generations and is a member of the American Society for Reproductive Medicine, the American Psychological Association, the Los Angeles County Psychological Association, the Lesbian and Gay Psychotherapy Association, and the Gay and Lesbian Medical Association. She is on the national Emeritus board of the Family Equality Council. Dr. Bergman writes, teaches and speaks extensively on parenting by choice. Along with co-authors, she published “Gay Men Who Become Fathers via Surrogacy: The Transition to Parenthood” (Journal of GLBT Family Studies, April 2010). Dr. Bergman’s is the author of the book, Your Future Family: The Essential Guide to Assisted Reproduction (Conari Press 2019) as well as the children's book You Began as a Wish (Independent Press 2019). Dr. Bergman created her own family using third party assisted reproduction and she lives with her wife of 35 years. She has two adult daughters.