The stomach still feels bulging on the eighth day of IVF transfer of frozen embryos, which may be caused by progesterone action, ovarian hyperstimulation, digestive tract diseases, etc. 1. Progesterone effect: in vitro transfer of frozen embryos need to be supplemented with progesterone to support pregnancy, the placenta will also secrete progesterone after a successful transplantation, the increase in the level of progesterone in the body may lead to gastrointestinal peristalsis slows down, slowing down the gastrointestinal emptying time, which in turn has a bulging stomach. 2. Ovarian hyperstimulation: IVF transplantation of frozen embryos may have multiple follicular development, high estrogen in the body, the bilateral ovaries due to overstimulation of the enlargement, but also cause an increase in vascular permeability, the blood through the blood vessel wall accumulates in the interstitial space in the tissues, the blood volume decreases and the blood is concentrated, which will lead to the performance of the bulging stomach after the eighth day of transplantation. 3. Digestive disorders: female patients with digestive disorders, such as indigestion, gastrointestinal dysfunction, etc., will also have a bulging stomach on the eighth day of IVF transfer of frozen embryos. If you still have a bulging stomach on the eighth day of IVF transfer, or if you have other uncomfortable symptoms, we recommend that you consult a doctor in time for treatment.