Week-by-Week Embryo Development Timeline

Embryo development doesn’t just happen overnight. This article breaks down your embryo’s development by week so you can know how it works.

You and your surrogate will share in the two parts of embryo development.

  1. In IVF for surrogacy, the first week of embryo development primarily unfolds in the laboratory setting, where the developing embryos are closely monitored and nurtured to the blastocyst stage.
  2. Once transferred to the surrogate, the next two weeks of development shift to the phase of implantation and early gestational development within the surrogate’s uterus. 

When your embryos are created, the last thing you’ll want to do is continue waiting to move forward in your journey. Parenthood is something you have been waiting to experience for years. 

By filling out our contact form online, you can learn more about creating your intended parent profile and surrogacy planning questionnaire during the developmental stages so you can hit the ground running on finding the perfect surrogate when your embryos are ready. 

Having an understanding of the embryo development stages week by week fafter the embryo transfer will give you a look at how to best prepare for what’s to come. 

 

Embryo Development By Week 1: Embryo Development

Embryo development begins as soon you create an embryo through in-vitro fertilization (IVF). This fusion of sperm and egg will eventually become a fetus, but there are several stages of development that happen in the first week. 

Day 1: Zygote
 

A zygote is a fertilized egg. Eggs are evaluated for fertilization 16-18 hours after combining your egg with the sperm of the intended father or donor.  

Day 2-3: Two-cell to eight-cell stage
 

Also called the cleavage stage, where cells begin to divide. Cell division increases exponentially after these days.

Day 4: Morula
 

A solid ball of cells resulting from the cleavage stage that happens after fertilization but before those cells turn into a blastocyst.

Day 5-7: Blastocyst
 

The condensed mass of cells that has split into two groups forming the trophectoderm and the inner cell mass. 

Embryo Development By Week 2: Post Transfer Implantation

Once the embryo reaches the blastocyst stage, it could be time for the embryo transfer unless a day three transfer already occurred or a frozen embryo transfer is recommended by your doctor.

Once the embryo is transferred to your surrogate’s uterus, it requires a two-week wait for the implantation process before your surrogate can test for a pregnancy. 

Here’s what’s happening with embryo development by week two: 

  • Day 1 and 2

    The blastocyst hatches and begins to try and attach itself to the uterus.

  • Day 3-5

    Implantation begins as the blastocyst works deeper into the uterine lining. The cells that form the placenta and fetus begin to develop.

  • Day 6

    Cell division continues as hCG begins to be produced.

  • Day 7 and 8

    Development continues as more hCG is released into the bloodstream. 

Embryo Development By Week 3: Implantation Continues and Completes

By the third week, hCG levels may have become high enough where a pregnancy may be detectable. 

Waiting the entire two weeks after the transfer is essential for embryo development by week because testing any earlier could result in a false positive for your surrogate due to any medications taken for the embryo transfer.

There also may not be enough hCG in her bloodstream yet to detect a pregnancy, leading to a false negative test. 

Once the two weeks are up, she can take a blood test at the fertility clinic to test for pregnancy as these tests are more reliable in detecting a pregnancy than an at-home test. 

If you haven’t connected with a fertility clinic yet, contact us online. We’ll provide you with a list of reputable clinics near you that you can choose from that meets all your needs.