What a mock cycle tests
A mock cycle is a practice run of the medication protocol, without an embryo transfer. You take the same medications on the same calendar you would for the real cycle. The clinic watches how your body responds.
The main question is your uterine lining. Estrogen builds the lining, and the clinic wants it to reach 7 to 8 millimeters or more, with the right appearance on ultrasound. A mock cycle shows whether the standard doses get you there, and how long it takes. If they do not, the clinic can adjust before a real embryo is involved.
A mock cycle also shows how you handle the medications day to day: whether Lupron gives you headaches, whether patches irritate your skin, whether the schedule fits your work. It is the same protocol described on surrogate medications, run once as a test.
You are not stimulating your ovaries, and no eggs are retrieved. In gestational surrogacy the embryo comes from the intended parents or from donors.
What a mock transfer is
Many clinics add a mock transfer at the end of the mock cycle. The reproductive endocrinologist passes an empty, thin catheter through your cervix into the uterus, the same way the embryo will travel on transfer day.
It lets the doctor map the path through your cervix and measure the depth of your uterus. If your cervix curves or is tight, the doctor knows before the real transfer and can plan for it. On transfer day, that means a smoother, quicker procedure.
A mock transfer feels like a Pap smear. No anesthesia is needed. It takes a few minutes. Some clinics do it at your medical screening visit instead of during a mock cycle.
What an ERA biopsy adds
Some clinics add an ERA, which stands for endometrial receptivity analysis. It is a small biopsy of your uterine lining taken during the mock cycle, at the point when the embryo would normally be transferred.
The sample is sent to a lab, which reads whether the lining is ready to accept an embryo on that day, or a little earlier or later. The clinic then times the real transfer to match.
An ERA biopsy causes brief cramping, similar to a strong period cramp. Not every clinic uses ERA testing, and those that do may use it only in certain cases. Your clinic decides.
How long a mock cycle takes
A mock cycle takes about four to six weeks from the first medication to the last monitoring visit. If an ERA is done, results take additional time before the real cycle can start.
| Mock cycle | Real cycle | |
|---|---|---|
| Medications | Lupron and estrogen, on the real calendar; progesterone if a mock transfer or ERA is timed | Lupron, estrogen and progesterone in oil, continuing into early pregnancy |
| Monitoring visits | Blood work and ultrasounds near home | Blood work and ultrasounds near home |
| Procedures | Possible mock transfer; possible ERA biopsy | Embryo transfer at the intended parents' clinic |
| Duration | About four to six weeks | Several weeks to transfer, then about 10 to 12 weeks of progesterone, tapered on the clinic's instruction |
| Payment | $500 medication start fee, monthly allowance, travel and lost wages | $500 medication start fee, $1,000 transfer fee, monthly allowance, travel and lost wages |
The medications in a mock cycle vary by clinic; protocol details are under review by Mark Silverberg, MD.
Which clinics require a mock cycle and which skip it
Not every clinic requires a mock cycle. PLS works with 14 partner fertility centers, including Kindbody, Shady Grove Fertility, Fertility Centers of Illinois and Oregon Reproductive Medicine, and each sets its own protocol.
Many clinics go straight to the real cycle when:
- You are an experienced surrogate and your last cycle went well.
- Your saline sonogram and your history are reassuring.
- The clinic has other ways to check the path for transfer.
A clinic is more likely to ask for a mock cycle if this is your first journey, if your lining has never been measured on medication, or if the intended parents have few embryos and want every step tested first.
If your clinic requires one, it adds time before the real cycle. Your case manager will build it into your calendar. The full order of steps is on the surrogate process.
What happens if your lining does not respond
If your lining does not reach the target, it is not a failure and not usually the end of the journey. It is information.
The clinic has several options. It may raise the estrogen dose, switch from patches to injections or pills, or extend the time on estrogen. It may order a test to look inside the uterus for something that is affecting the lining. Then it may run a second mock cycle on the new plan.
Mark Silverberg, DDS, MD, will already have read your prenatal and delivery records before you reached the clinic, so the reproductive endocrinologist starts with your full history. See medical screening.
In rare cases the lining does not respond well enough even after changes. The clinic will tell you and the intended parents what it found and what it recommends. Your case manager walks through the options with you.
Is a mock cycle paid?
Yes. The $500 medication start fee applies to a mock cycle, as well as to the real cycle. The monthly allowance continues. Travel and lost wages for any appointments are reimbursed.
The intended parents pay for the mock cycle: medications, monitoring and any procedures. You do not receive a bill. For context, a first-time PLS surrogate carrying one baby receives a core package of about $67,200, built on $60,000 base compensation, and a typical total of $68,000 to $78,000 once typical lost wages and optional pumping payments are included.
After the mock cycle, the next step is the real cycle and transfer day. If you are not yet in the process, start with the prescreen: see if you qualify.
Sources
- American Society for Reproductive Medicine (ASRM), patient resources on frozen embryo transfer and gestational carriers. https://www.asrm.org
- Private Label Surrogacy compensation schedule, 2026.