On the evening of the day of transplantation, there was a sensation of soreness and bloating in the lower abdomen.

Transplantation usually refers to embryo transfer. Aching and bloating in the lower abdomen on the evening of embryo transfer may occur due to prolonged urine retention, surgical stimulation, or embryo implantation. Appropriate management should be based on the individual patient's condition. The specific causes are analyzed as follows:

1. Prolonged Urine Retention

Embryo transfer is primarily indicated for individuals with infertility and is a form of assisted reproductive technology. It involves surgically placing a fertilized egg into the uterine cavity to achieve pregnancy. During the procedure, patients are required to retain urine to fill the bladder, which helps visualize the optimal implantation site for the embryo. If urine is retained for too long, abnormal distension of the bladder wall may cause aching and bloating in the lower abdomen on the evening of the transfer. This is a normal phenomenon and typically resolves spontaneously.

2. Surgical Stimulation

During the procedure, the uterine cavity may experience some physical contact. Improper technique or excessive force can lead to local mucosal congestion, resulting in this symptom. After surgery, it is recommended to ensure adequate rest and avoid strenuous activity.

3. Embryo Implantation

When the fertilized egg implants, its outer layer of cells penetrates the endometrium and connects with maternal blood vessels. During this process, small gaps may form in the endometrial lining, potentially causing capillary rupture and leading to the aforementioned symptoms. It is advisable to maintain good personal hygiene and avoid sexual intercourse in the short term.

In addition, other possible causes include excessive fatigue, overeating, and gastroenteritis. In daily life, it is recommended to consume high-protein, high-vitamin foods, maintain regular bowel movements, wear loose clothing, and avoid excessive tension or anxiety.