What Is Mock Cycle in Surrogacy?

Last updated: March 28, 2026 · SurroScore Research Team · Based on data from 196+ surrogacy agency compensation packages

A mock cycle (also called a trial cycle) is a preparatory hormone treatment that simulates a real embryo transfer cycle, allowing the fertility clinic to evaluate how a surrogate's uterine lining responds to medications before committing to an actual transfer.

Why Mock Cycle Matters for Surrogates

Think of the mock cycle as a dress rehearsal. It helps the medical team confirm your body responds well to the hormone protocol, achieve the right uterine lining thickness, and practice the timing before the stakes are real. Many agencies pay a small compensation for mock cycle participation.

How Mock Cycle Works in Surrogacy

A mock cycle typically involves:

2–4 weeks of estrogen (patches, pills, or injections) to build uterine lining
Monitoring appointments (ultrasound + blood draws)
Addition of progesterone to simulate the post-transfer phase
Uterine lining check and clinical evaluation
No embryo is transferred — it's just to test your response

Real-World Example

If your lining reaches the target thickness (typically 8mm or more) during the mock cycle, you're cleared to proceed to a real transfer cycle. If not, the clinic adjusts the protocol before your actual transfer. The mock cycle also sometimes includes an endometrial biopsy to test for receptivity.

Frequently Asked Questions

What is a mock cycle in surrogacy?

A mock cycle is a practice run of the medication protocol and monitoring process without actually transferring an embryo. It helps the fertility clinic verify that the surrogate's uterine lining responds properly to medications and fine-tune the dosage before the real transfer.

Why do surrogates do a mock cycle?

A mock cycle lets the fertility clinic confirm your body responds well to the hormone protocol. They measure uterine lining thickness and pattern to ensure optimal conditions for embryo implantation — without the cost and emotional stakes of using an actual embryo.

Do all surrogates have to do a mock cycle?

Not always. Some clinics require mock cycles for all surrogates; others only require them if there are concerns about lining response. It depends on the fertility clinic's protocol and the surrogate's medical history.

Related Surrogacy Terms

Embryo Transfer Frozen Embryo Transfer (FET) Medical Clearance IVF (In Vitro Fertilization) Beta-hCG

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Source: SurroScore's proprietary database of surrogate-reported compensation data and agency compensation packages, collected from direct agency outreach, public filings, and verified surrogate reviews. Data current as of March 2026.