Induced abortion is one of the remedial measures for unintended pregnancy and contraceptive failure[18]. At present, the most used method is negative pressure suction. The main complications of this operation include intraoperative and postoperative bleeding[19], uterine perforation, leakage of aspiration or incomplete aspiration leading to postoperative re-clearance of the uterus, chronic pelvic inflammatory disease, postoperative intrauterine adhesions[20], and even secondary infertility[21], which seriously endanger the physical and mental health of women[22] and thus have an impact on society and family [23]. The number of abortion patients in China is climbing stably year by year[24], especially the proportion of young and childless women. Therefore, it is of positive clinical significance to actively prevent and early intervention complications after induced abortion, promote the rehabilitation of patients after abortion, reduce and avoid reproductive tract damaged.
Neuromuscular electrical stimulation is a kind of low-frequency electrical stimulation that uses an electrical stimulator to activate or inhibit excited cells by acting on biological tissues with specific parameters of pulsed current in a controlled way, thus causing functional changes of the organs and tissues[25]. It is also called biomimetic electrical stimulation because its stimulation frequency is 1000mz, compared with the normal human body, 1ms of the absolute refractory period of the motor nerve is low frequency. It is characterized by exciting neuromuscular tissue, destroying membrane polarization state by electrical stimulation, thus causing neuromuscular excitation, promoting blood and lymphatic circulation, and playing the role of repairing injured muscle tissue and nerve. Clinically, it can relieve muscle tension, improve the pain threshold to relieve pain, facilitate the repair of nerve-muscle and improve tissue blood supply and lymphatic circulation[26]. Neuromuscular electrical stimulation was first applied in the clinic in the 1970s. Now it plays a vital role in the recovery of the body after trauma, the recovery of spinal cord injury[27], the neuromuscular rehabilitation of paralyzed patients[28], and even improving the motor function of children with cerebral palsy[29].
The earliest application of neuromuscular electrical stimulation in the field of gynecology and obstetrics is mainly in the rehabilitation of the pelvic floor muscles[30]. It has been previously believed that NMES can stimulate the shallow and deep pelvic floor muscles and nerves of the pelvic floor through low-frequency pulses, promote the contraction of muscle groups, especially the contraction and muscle strength of the shallow and deep I and II muscle groups, which has a positive effect on postpartum urinary incontinence[31] [32]and after cervical cancer operation[33]. Besides, other studies believe that it plays a positive role in promoting the blood supply and lymphatic circulation of pelvic floor tissues and organs which can effectively reduce the pain caused by uterine contractions[10]. On the other hand, NMES can promote the smooth muscle relaxation of the uterine artery, reduce the resistance of uterine artery blood flow, accelerate the blood flow velocity, thus promoting the growth of endometrium or improving the local blood flow perfusion of the uterus, which is conducive to the repair of the endometrium. It has been reported that NMES before embryo transfer can accelerate the growth of the endometrium and prepare for embryo implantation[9].
Based on the previous research, NMES after artificial abortion is combined with electrical stimulation treatment on the comprehensive characteristic, generate low-frequency pulse electrical stimulation therapy apparatus, stick in the lumbar di ministry, through the projection area of the uterus and other specific parts of the skin, make the multiple electrode percutaneous import in the target area, making specific parts of a biological membrane polarization cell vibrations, To improve the muscle contraction in the region, accelerate blood circulation, clinically strengthen uterine contraction, reduce postoperative vaginal bleeding time, help repair the endometrium, reduce postoperative intrauterine adhesion. Finally, it can effectively reduce the complications of induced abortion.