
General Fertility
October 3, 2023 at 6:58:00 PM
Human pregnancies are counted in weeks, with 40 weeks being considered full term. Many people don’t realize that when using IVF, you don’t begin counting those 40 weeks on the day you transfer the embryo into your uterus. Gestation is determined by the age of the egg as opposed to the time spent carrying it. In this way, you are transferring an embryo into your uterus that already has an age assigned to it.
In a traditional pregnancy, gestational age begins accumulating on the last day of your menstrual period. By the time conception occurs, the gestational age is already somewhere around two weeks. Therefore, gestational age in IVF, and by virtue in surrogacy, begins accumulating well before transfer.

HOW OLD IS AN EMBRYO WHEN IMPLANTED WITH IVF?
The nature of IVF allows for more specific date stamping. In these instances, the exact date of ovulation, fertilization, and conception are known. This adds up to a clearer picture of gestational age. Here are 2 examples:
Transferring a 3-day embryo will leave you 2 weeks and 3 days pregnant as you leave the office.
A 5-day embryo is equivalent to a gestational age of 2 weeks and 5 days.
At the close of the 2-week wait between transfer and beta pregnancy test, you could be up to 5 weeks pregnant, depending on the age of your embryo at transfer. (You can learn more about an embryo's development before and after transfer in our related blog post.)
WHEN IS MY DUE DATE WITH IVF?

Due dates for surrogates are determined based on the individual circumstances of the baby and mother. As you may have guessed, calculating your due date requires a slightly different approach when you've conceived via IVF compared to a spontaneous pregnancy. With IVF, the estimated date of your baby's arrival will be based on your embryo transfer date.
CALCULATING YOUR GESTATIONAL DUE DATE
Calculating gestational age and due date in IVF can be confusing. A number of terrific online calculators are available to help you get an accurate age and due date. More reliably, your case specialist or nurse should also be able to help you nail down a specific date and gestational age.
DETERMINING IVF GESTATIONAL AGE & DUE DATE

An exact gestational age and estimated due date will be determined at the first ultrasound based on the size of the gestational sac and the fetus inside. Multiple pregnancies are more common in IVF. These pregnancies are often delivered before 40 weeks gestation.
Contact Growing Generations for more information.
Human pregnancies are counted in weeks, with 40 weeks being considered full term. Many people don’t realize that when using IVF, you don’t begin counting those 40 weeks on the day you transfer the embryo into your uterus. Gestation is determined by the age of the egg as opposed to the time spent carrying it. In this way, you are transferring an embryo into your uterus that already has an age assigned to it.
In a traditional pregnancy, gestational age begins accumulating on the last day of your menstrual period. By the time conception occurs, the gestational age is already somewhere around two weeks. Therefore, gestational age in IVF, and by virtue in surrogacy, begins accumulating well before transfer.
HOW OLD IS AN EMBRYO WHEN IMPLANTED WITH IVF?
The nature of IVF allows for more specific date stamping. In these instances, the exact date of ovulation, fertilization, and conception are known. This adds up to a clearer picture of gestational age. Here are 2 examples:
Transferring a 3-day embryo will leave you 2 weeks and 3 days pregnant as you leave the office.
A 5-day embryo is equivalent to a gestational age of 2 weeks and 5 days.
At the close of the 2-week wait between transfer and beta pregnancy test, you could be up to 5 weeks pregnant, depending on the age of your embryo at transfer. (You can learn more about an embryo's development before and after transfer in our related blog post.)
WHEN IS MY DUE DATE WITH IVF?
Due dates for surrogates are determined based on the individual circumstances of the baby and mother. As you may have guessed, calculating your due date requires a slightly different approach when you've conceived via IVF compared to a spontaneous pregnancy. With IVF, the estimated date of your baby's arrival will be based on your embryo transfer date.
CALCULATING YOUR GESTATIONAL DUE DATE
Calculating gestational age and due date in IVF can be confusing. A number of terrific online calculators are available to help you get an accurate age and due date. More reliably, your case specialist or nurse should also be able to help you nail down a specific date and gestational age.
DETERMINING IVF GESTATIONAL AGE & DUE DATE
An exact gestational age and estimated due date will be determined at the first ultrasound based on the size of the gestational sac and the fetus inside. Multiple pregnancies are more common in IVF. These pregnancies are often delivered before 40 weeks gestation.
Contact Growing Generations for more information.
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