Incomplete involution of the uterus

　　The common causes of incomplete uterine involution include partial retention of placenta and amnion; endometritis, myometritis, or pelvic infection caused by postpartum infection; retention of lochia due to excessive retroversion or lateral flexion of the uterus; intramural fibroids, adenomyosis; excessive uterine expansion during pregnancy, such as multiple pregnancies, polyhydramnios, macrosomia, etc. The specific causes and attention mechanisms are described as follows.

　　First, etiology

　　1. Retention of placenta, amnion, and incomplete decidua.

　　2. Endometritis, myometritis, or pelvic infection.

　　3. Uterine fibroids, such as intramural fibroids and adenomyoma.

　　4. Excessive retroversion or lateral flexion of the uterus, which leads to poor expulsion of lochia and causes lochia to remain in the uterine cavity.

　　5. Large placental area (such as multiple pregnancies, placenta previa, etc.) affects uterine involution because the muscular layer at the site of placental attachment is thin, and the uterine contraction force is significantly weakened.

　　6. Multiparous women have relatively increased uterine fibrous tissue due to multiple deliveries, which affects the uterine contraction force.

　　7. Over-inflation of the bladder or the bladder frequently being in an over-inflated state, which is most common in postpartum urinary retention.

　　Second, pathogenesis

　　After delivery, due to the contraction and involutionary action of the uterine muscle, it forces the vascular lumen within the muscular layer to become occluded or narrowed, leading to ischemia of the uterine muscle cells or autolysis. The uterine volume decreases significantly, and the placental detachment surface is also repaired with the shrinkage of the uterus and the growth of the new endometrium. Generally, it can recover to a non-pregnant state within 5-6 weeks after delivery. This process is called uterine involution, and when the above involutionary function is obstructed, it leads to incomplete uterine involution.

　　The main complications of incomplete uterine involution are infections, including endometrial, pelvic, and systemic infections. After the cessation of blood-like lochia, if purulent secretions are discharged, it indicates the presence of endometritis.

　　The most prominent clinical manifestation of incomplete uterine involution is the prolonged duration of blood-like lochia, which extends from the normal duration of only 3 days to 7-10 days, even longer. If the cause is placental retention, the duration of blood-like lochia is prolonged, and the blood volume is also significantly increased, at this time, lochia is often turbid or accompanied by an odor.

　　Sometimes, necrotic retained placental tissue and/or fetal membrane tissue can be seen to be discharged along with lochia. After the bloody lochia stops, if purulent secretions are discharged, it indicates that there is endometritis. During this period, the patient often has back pain and a feeling of lower abdominal distension, but there are also a few patients with very little bloody lochia, and mainly there is severe pain in the lower abdomen.

　　During bimanual examination, it is often found that the cervix is softer, the external os of the cervix can at least pass one finger, the uterus is slightly larger and softer than the normal postpartum uterus of the same period, most of the uterus is in a retroverted and retroflexed position, and there is mild tenderness. When incomplete uterine involution is caused by endometritis, myometritis, or pelvic infection, the tenderness of the uterus is more obvious, and there is also tenderness of varying degrees in the adnexal area.

　　The prevention of incomplete uterine involution includes enhancing the physical condition of the pregnant woman during pregnancy; properly handling the delivery of the placenta and membranes during labor; and timely urination within 4 hours after the placenta is delivered, etc. The specific preventive measures are described as follows.

　　8. During pregnancy, all measures that can enhance the physical condition of the pregnant woman should be paid attention to.

　　7. During labor, it is necessary to properly handle the delivery of the placenta and membranes. The delivered placenta and membranes should be carefully checked for completeness, and attention should be paid to check for any ruptured blood vessels at the edge of the fetal surface of the placenta to be able to detect accessory placenta in time. If there is a suspicion of accessory placenta, partial placental retention, or most of the membranes retained, all retained tissues should be removed from the uterine cavity by hand under strict sterile operation. If after checking the membranes, it is confirmed that only a small amount of membranes are retained, uterine contraction agents and antibiotics can be applied postpartum to wait for their natural expulsion and to prevent infection.

　　6. To avoid postpartum urinary retention, instruct the mother to urinate in the first 4 hours after the placenta is delivered. If she still cannot urinate spontaneously 6 hours after delivery and is diagnosed with urinary retention, it should be treated promptly, and catheterization may be necessary if necessary.

　　5. Instruct the mother to avoid prolonged supine position and encourage her to get out of bed early. If the diagnosis is retroverted and retroflexed position of the uterus, chest-knee position should be performed twice a day, each for 15-20 minutes to correct it.

　　4. Strengthen the care during labor and puerperium as much as possible to prevent the occurrence of incomplete uterine involution. If there is a suspicion of retained products, the uterine cavity should be cleaned immediately, and uterine contraction agents should be administered to promote uterine contraction, and prophylactic antibiotics should be used. Actively treat postpartum urinary retention. Once postpartum urinary difficulty occurs, it should be treated as soon as possible, such as applying heat to the lower abdomen, acupuncture, moxibustion, and point closure with neostigmine. If urine is still not fully voided, and the bladder is distended to near the umbilical level, continuous catheterization should be performed. Avoid prolonged supine position after delivery and get out of bed as soon as possible. For those with excessive bleeding or prolonged bleeding, an ultrasound examination should be performed. If there are retained products in the uterine cavity, curettage should be performed. The extracted material should be sent for pathological examination. If there is fever and an increase in white blood cells, infection may have occurred. In this case, start with a large dose of broad-spectrum antibiotic treatment while performing bacterial culture of the uterine cavity contents. For those who do not respond to conservative treatment, surgical treatment can be considered. Depending on the condition of the myoma, myomectomy can be performed, and rarely is it necessary to perform hysterectomy.

　　The examination of incomplete uterine involution includes laboratory tests and auxiliary examinations, and the specific examination methods are described as follows.

　　1. Laboratory examination

　　Blood, urine, stool routine and other examinations should be selected according to the condition.

　　2. Other auxiliary examinations

　　Ultrasonic examination of type B, if the uterus is larger and there is a residual placenta or decidua image in the uterine cavity, it can be diagnosed as incomplete uterine involution caused by placental retention or decidua retention; if the image of intermuscular myoma or adenomyoma of the uterus is seen, it can be diagnosed as the cause of incomplete uterine involution.

　　In addition to conventional treatment, attention should also be paid to the following aspects of diet for patients with incomplete uterine involution: patients should have a light diet, rationally mix and match meals, pay attention to nutritional balance, eat more vegetables and fruits; avoid spicy and刺激性 foods.

　　When there is incomplete uterine involution, uterine contraction agents should be administered. Different treatment methods should be adopted for incomplete uterine involution caused by different reasons, and the specific treatment methods are described as follows.

　　When there is incomplete uterine involution, uterine contraction agents should be administered. The most commonly used drugs include: ergometrine O.2～O.4mg, twice a day, intramuscular injection; oxytocin 10～20U, twice a day, intramuscular injection; ergot tincture 2ml, three times a day, oral; angelica sinensis granules 2g, three times a day, oral; Shenghuang decoction 25ml, 2～3 times a day, oral; Shufukang granule 20g, three times a day, oral. All of the above drugs should be used for at least 2 to 3 consecutive days.

　　When diagnosed with incomplete uterine involution caused by partial placental retention or most of the decidua retention, as it is often accompanied by mild infection of the endometrium and/or myometrium, it is necessary to take cefalexin 1g and metronidazole 0.2g orally, 4 times a day, for 2 consecutive days before curettage to prevent the spread of infection. It is necessary to thoroughly remove the retained tissue and decidua of the uterus to achieve the dual purpose of hemostasis and pathological examination, and pay attention to exclude choriocarcinoma of the uterus. After the operation, uterine contraction agents should be given to promote uterine contraction, and broad-spectrum antibiotics should be used for 1 to 2 days.

　　If the cause of incomplete uterine involution is intermuscular myoma of the uterus, mainly apply uterine contraction agents. If there is no significant effect after several days of treatment, and the vagina still continues to bleed in large quantities, consider hysterectomy.