An Ideal Embryo Transfer Window

After a failed embryo transfer, many women wonder what can be done to improve future chances of success. In some cases, the doctor may perform an endometrial receptivity analysis (ERA) to gather more information about the previous failure to implant. An ERA tests a small sample of the endometrial lining to determine the best day for embryo transfer during the next in vitro fertilization (IVF) cycle. With a targeted window for transfer, success rates can increase.


A receptive endometrium

What’s so important about the endometrium? Whether a pregnancy is natural or achieved with assisted reproductive technology (ART) like IVF, the embryo must first implant into the endometrium to stick. The endometrium is the layer of tissue that lines the uterus. During the menstrual cycle, an increase in progesterone leads to a thickening of the endometrium, priming the area for implantation should an embryo appear. During IVF, endometrial thickness is an essential factor contributing to the overall success of the procedure.

How an ERA is performed

If a doctor recommends an ERA, the patient’s endometrial lining and hormones will be monitored closely with blood work and ultrasound. A mock cycle will be performed using medications like progesterone to mimic what will happen during IVF treatment. Once the endometrium is prepared, a sample is biopsied for testing. The small amount of tissue is sent to the lab, where a fertility specialist can analyze specific genes that play a role in receptivity.

Possible side effects

The ERA procedure is performed outpatient, and no anesthesia is used. The patient may experience cramping and discomfort during and after the procedure, but symptoms should resolve quickly. Over-the-counter (OTC) medication can help with the pain following the biopsy.

Results of the biopsy

There are 3 possible results when an ERA is performed. If the endometrium is determined to be receptive, the protocol used during the mock cycle is ideal, and the transfer can occur during the same window in which the biopsy was performed. A pre-receptive result means the patient was not on progesterone long enough, and the lining was not adequately receptive. A post-receptive result means the biopsy was taken past the ideal time, and future embryo transfers should occur earlier in the cycle. Sometimes the doctor will want to repeat the test.

Who benefits from ERA?

Although any woman undergoing IVF can benefit from an endometrial receptivity analysis, the procedure is typically recommended for higher stakes. Women with a history of unsuccessful transfers or a limited number of embryos available and patients using donor eggs or embryos are often considered good candidates for ERA testing.

Timing is everything

Pregnancy is a delicate process, and optimal timing can make a huge difference between another failed cycle and a positive pregnancy test. Endometrial receptivity testing is a great way to practice an IVF cycle and determine the optimal time for embryo transfer. With ERA results, patients are more likely to achieve a pregnancy using fertility treatment.

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