You’ve shown up for all of the appointments. You’ve endured every single at-home injection. You’ve taken your prenatal vitamins and prescribed IVF meds. Your eggs have been retrieved and fertilized, and now it’s time for the final step of the IVF process: embryo transfer. 

Everything has been preparing you for this step, building up to this moment. Depending on how you and your team of doctors decide to conduct the transfer, it could happen a few days after egg retrieval, during your next menstrual cycle, or even months or years down the line. 

With all of the hope, fear, and excitement you’re probably feeling, here’s what you can actually expect during an embryo transfer cycle, whether it’s fresh, frozen, or natural. 

What Is An Embryo Transfer?

As stated, embryo transfer is the final step of the IVF process. After the patient’s eggs are harvested, they will be fertilized and grow for several days into an embryo. The embryo is then transferred back into the woman’s uterus where it will, hopefully, implant, attaching itself to the endometrial lining of the uterus. 

The embryo transfer itself is relatively non-invasive and similar to that of a pap smear. The doctor will insert a speculum into the vagina to keep the walls propped open, and with ultrasound guidance, the doctor will insert a catheter through the cervix and into the uterus. The embryo(s) will then be passed through the catheter tube and into the patient’s womb. 

While an embryo transfer is generally painless, rarely requiring sedatives, some women might feel some slight discomfort, cramping, or light spotting following the procedure. 

We spoke with Dr. Michael DiMattina, MD, Founder and Medical Director of Dominion Fertility, about the different types of embryo transfers and what he sees, recommends and performs most often in his own practice.

Fresh Embryo Transfer

An embryo transfer is considered a “fresh transfer” when it happens during the same menstrual cycle that the eggs are harvested, usually on day-3 or day 5 post-egg retrieval. 

woman holding a tablet and smiling

“This practice, however, isn’t as popular anymore because, for over a decade now, many studies have demonstrated that transferring embryos fresh in the same cycle that the eggs were retrieved results in lower implantation rates,” explains Dr. DiMattina. “This is because the hormones used to stimulate the ovaries to drive up the patient’s estrogen levels very high for a short period of time. These increased hormones are good for egg retrieval but can have an adverse effect on the endometrial lining of the uterus in 40% of patients. Of course, we don’t know which patients will fall in that 40%, so it is far better to take the embryos that are produced, freeze them, and then transfer them outside of the stimulation cycle. You get far higher pregnancy rates.”

Frozen (Medicated) Embryo Transfer 

Transferring frozen embryos can be done in two different ways: medicated or natural. 

“During a medicated cycle, we try to create, if you would, a perfect menstrual cycle by using the naturally occurring hormones: estrogen and progesterone,” says Dr. DiMattina. “This results in much higher pregnancy rates than an embryo freshly produced.”

Not only does this allow for estrogen levels to come back down after the egg retrieval, but medicated cycles also give the patient and doctor more control over the schedule, ensuring the timing is just right and occurs when both parties are available.

“My personal implantation rate is about 70%. In other words, every time I transfer one thawed frozen embryo into a patient, she has a 70% chance that it will implant. Then most—not all— but most of those pregnancies will then go to term.” 

According to Dr. DiMattina, a medicated frozen transfer is roughly a 4 to 6-week process. However, it allows for flexibility as the embryos are frozen and can be used up to 10 years down the line, providing that the patient’s uterus is still able to sustain a pregnancy. 

Natural Embryo Transfer

For some doctors and patients, a “natural” transfer might be the preferred method of transfer for thawed frozen embryos. 

“The second way we can transfer a frozen-thawed embryo is in a natural menstrual cycle,” explains Dr. DiMattina. “In other words, if the patient has natural, regular menstrual cycles, then we can use that cycle and transfer the embryo. The problem with that is the timing is hard to predict.”

For patients with regular menstrual cycles and “normal” ovarian function, a natural transfer is an option that allows for less medication – and therefore, fewer side effects – during IVF. However, natural transfer cycles offer considerably less flexibility when it comes to the transfer date, more frequent monitoring appointments, and an increased risk of transfer cancellation from premature ovulation. So, for those who thrive on predictability, a natural embryo transfer cycle may not be the best option. 

Trust Your Care Team

Whether it’s fresh, frozen, or natural, it’s important to discuss your embryo transfer options with your care team to come up with the best plan of action for you. After all, they want to see you pregnant just as much as you do! 

“The only thing I enjoy more than doing embryo transfers is doing the obstetrical sonograms, showing patients the baby and the baby’s heart rate,” says Dr. DiMattina.

Brighid Flynn is a freelance writer based in Philadelphia where she lives with her husband and puppy. She is just beginning her journey toward motherhood.