An hCG wash is a fertility procedure in which a small amount of human chorionic gonadotropin (hCG) is infused directly into the uterus shortly before an embryo transfer during IVF. The goal is to prime the uterine lining so an embryo has a better chance of implanting. It’s also called an intrauterine hCG infusion or hCG perfusion, and it’s most commonly offered to people who have experienced repeated failed embryo transfers.
How the Procedure Works
The “wash” part of the name is somewhat misleading. Nothing is being rinsed or cleaned. Instead, a very small volume of fluid, typically about 1 milliliter of culture media containing hCG, is gently deposited into the uterine cavity using a thin catheter. The process is similar to the embryo transfer itself and takes only a few minutes. Most patients describe it as comparable to an IUI or a Pap smear in terms of discomfort.
The standard dose used in most studies is 500 international units (IU) of hCG. Research comparing different timing windows found that the best results occurred when the infusion was given 5 to 12 minutes before the embryo transfer. Infusions done hours or days beforehand, or immediately before transfer, did not show the same benefit for live birth rates.
What hCG Does to the Uterine Lining
hCG is a hormone the body naturally produces during early pregnancy. When placed directly inside the uterus, it triggers several changes that make the lining more hospitable to an embryo. It promotes the growth of new blood vessels, increases blood flow to the uterine wall, and shifts the balance of immune signaling molecules in a way that supports implantation rather than rejection. These changes mirror what happens naturally when an embryo begins to attach: it secretes hCG as a chemical signal to the surrounding tissue.
The infusion essentially gives the uterine lining a head start. It boosts the expression of receptivity markers, proteins on the surface of the endometrium that help the embryo “dock” and begin embedding. It also supports decidualization, the process by which the lining transforms into the specialized tissue needed to sustain an early pregnancy.
Who It’s Typically Recommended For
The primary group offered an hCG wash is people with recurrent implantation failure (RIF), a condition that affects up to 10% of those undergoing IVF. The European Society of Human Reproduction and Embryology defines RIF as the failure to achieve a clinical pregnancy after at least three transfers of good-quality embryos, particularly in younger patients. If you’ve had multiple rounds of IVF where everything looked good on paper but the embryo simply didn’t stick, your clinic may suggest this as an add-on.
Some clinics also offer it to patients with endometriosis or other conditions that may compromise uterine receptivity, though the strongest body of evidence focuses on recurrent implantation failure specifically.
What the Evidence Shows
A 2024 meta-analysis pooling data from 13 studies and over 2,100 participants found that intrauterine hCG perfusion improved embryo implantation rates by roughly 37% in patients with recurrent implantation failure. The analysis also showed improvements in clinical pregnancy and live birth rates, though the authors described the benefit as modest.
In a study focused on patients with endometriosis, those who received the hCG infusion had a clinical pregnancy rate of 57.8%, compared to 39.3% in the control group. Live birth rates trended higher as well (46.7% versus 31.9%), though that particular difference didn’t reach statistical significance due to the small sample size.
These numbers are encouraging, but context matters. Most of the available studies are from single centers, and sample sizes remain relatively small. The procedure is considered a cost-effective option compared to other immune-based interventions for implantation failure, which is one reason it has gained traction, especially in clinics with fewer resources.
What to Expect as a Patient
If your fertility specialist recommends an hCG wash, it will happen on the same day as your embryo transfer. You’ll likely already be at the clinic, prepped, and in position. The catheter insertion takes a minute or two, after which you’ll wait roughly 5 to 12 minutes before the embryo is transferred through the same route. There’s no separate appointment, no anesthesia, and no recovery time beyond what you’d already plan for the transfer itself.
The procedure does not appear to carry significant additional risks beyond the embryo transfer process. Because the dose of hCG is small and delivered locally rather than into the bloodstream, systemic side effects are not a major concern. The main practical consideration is that it adds a small cost to your IVF cycle, which varies by clinic.
One important note: an hCG wash is not a standalone fertility treatment. It’s an adjunct, something added on top of a standard IVF or frozen embryo transfer cycle. It won’t help if the underlying issue is egg quality, sperm quality, or a structural problem with the uterus. Its role is narrow but meaningful: optimizing the environment right at the moment when implantation needs to happen.