What is birth canal injury?
The birth canal is the passage of fetal delivery, which is divided into two parts: the bone birth canal and the soft birth canal. The soft birth canal is a tube composed of the soft tissues of the lower uterus, cervix, vagina and pelvic floor. Birth canal injury is mainly the soft birth canal injury caused by childbirth, which is one of the common complications in obstetrics and one of the important causes of postpartum hemorrhage. Most of them occur in primiparas, especially in high primiparas.
Although there will be a series of changes in the birth canal before delivery, which is beneficial to the passage of the fetus, due to the influence of factors such as huge fetus, excessive labor force and rapid progress of labor, the cervical or/and vaginal wall is often broken before the fetus is delivered. Improper perineal protection when the fetal head is delivered, perineal edema without perineal incision or too small incision may cause perineal laceration.
In forceps assisted delivery, breech traction, fetal destruction and fetal head aspiration, if the cervix is not completely opened, forced delivery will often cause serious cervical laceration. Patients with mild birth canal injury may have bleeding and infection, while patients with severe birth canal injury may have anal sphincter injury or urinary fistula and fecal fistula. Severe cervical laceration may lead to abortion and premature delivery in the third trimester of pregnancy, or it may spread to the lower part of the uterus, leading to uterine rupture.
Causes of soft birth canal injury
1. High-risk population: Soft birth canal injuries are common in primiparas and elderly multiparas, especially primiparas under the age of 20, whose immature development, combined with mental stress and anxiety, often leads to perineal tears, while elderly multiparas are prone to injuries due to their relatively poor elasticity and toughness. The rapid expansion during labor can easily lead to the rupture of deep tissue blood vessels and the formation of hematoma.
2. Pregnancy complications: those with pregnancy complications are prone to soft birth canal injury, and those with pregnancy hypertension, pregnancy complicated with hematological diseases and liver and kidney dysfunction are prone to vulvar and vaginal edema, poor expansibility, increased brittleness, decreased coagulation function, laceration and hematoma.
3. Abnormal delivery: such as sudden delivery, delayed delivery, prolonged second stage of labor, abnormal position of fetal head, improper use of oxytocin, and reduction of fetal presentation caused by the impact of abdominal pressure during the second stage of labor, which directly causes tissue damage.
Iatrogenic factors:
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Improper perineal protection leads to soft birth canal injury. Iatrogenic factors include perineal incision signs and bad incision timing. Too small perineal incision can easily lead to serious perineal laceration when the fetus is delivered, and too early perineal lateral incision can also lead to excessive incision bleeding.
5. Improper operation of midwifery operation
Improper operation or focus deviation between the operator and the parturient, or poor coordination and uncoordinated movements are the main factors that directly cause the soft tissue tear of the birth canal. Including aspirator and forceps, especially forceps have obvious damage to the birth canal.
6. Bleeding did not stop completely when the lateral incision was sutured, and the laceration of cervix or vaginal vault was not found in time. For perineal laceration and lateral incision, if there is a dead space, or the wound is not stitched correctly, the wound is not stitched to it.
Manifestations of soft birth canal injury
The laceration of birth canal is the laceration of soft birth canal (lower uterus, cervix, vagina and perineum) during delivery. According to the location, they are called uterine rupture, cervical laceration and perineal vaginal laceration (perineal laceration), among which perineal vaginal laceration is the most common.
1, perineal laceration
It is most common during childbirth. It is divided into three degrees according to the depth of the injury.
First degree perineal laceration: refers to the laceration of perineal skin, hymen and vaginal mucosa, which does not reach the muscular layer and generally does not bleed much.
Second perineal laceration: refers to laceration reaching the perineal muscle layer, which can involve the posterior vaginal wall and even tear the lateral sulcus of the posterior vaginal wall. Laceration is often irregular and bleeding is often more.
Third-degree perineal laceration: refers to partial or total laceration of anal sphincter, even laceration of vaginal and rectal septum and partial anterior wall of rectum.
2, vaginal mucosal laceration
Most of them tear in the posterior wall of vagina, which can extend to the lateral vaginal groove and even reach the vaginal vault.
3. Cervical laceration
Cervical laceration often occurs on both sides. Patients with edema of the anterior cervical lip can break the anterior lip. Severe laceration of the cervix can reach the lower part of the uterus and may also damage the bladder. Occasionally, annular tearing and shedding of uterus and vagina can be seen.
Diagnosis of soft birth canal injury
1. Severe perineal vaginal laceration can extend to the fornix, paravaginal space, and even to the pelvic wall. The vagina is severely torn near the fornix, and its hematoma can extend upward to the broad ligament.
2. In the process of delivery, slight tearing of cervix is almost inevitable. Usually the laceration is shallow and there is no obvious bleeding, so the diagnosis of cervical laceration is not made. When the fetus passes through the incompletely opened cervix too quickly, a bleeding laceration of the cervix will occur. In severe cases, it can involve the vaginal vault downward and extending to the lower part of the uterus, leading to massive bleeding.
3. Every pregnant woman may have different degrees of laceration of the birth canal. However, if the fetus is too large, assisted by forceps, the birth canal is obviously edema or varicose veins, dystocia, emergency delivery, and the last fetus is delivered by caesarean section and this fetus tries to be a vaginal producer, it will increase the chance of serious laceration.
4. When examining the perineal incision, if the doctor finds that the bleeding point is not only in the perineum, but also the uterine contraction is very good at this time, it is highly suspected that there are other lacerations in the upper part of the birth canal. Sometimes the birth canal laceration loses blood quickly, and blood transfusion is needed before the wound suture is completed. Sometimes, although the wound no longer bleeds after suture, a hematoma will form in the deeper part of the laceration, which will lead to unstable vital signs or perineal swelling and pain in the postpartum ward.
Treatment of soft birth canal injury
Perineal laceration: the principle of treating superficial perineal vaginal laceration (degree ⅰ and ⅱ) is generally suture to stop bleeding; If the laceration is as deep as the anal sphincter or rectal mucosa (ⅲ degree), we must pay special attention to the repair of tissue structure, that is, the repair of the junction between rectal mucosa and anal sphincter, so as to avoid serious sequelae and even affect the defecation function.
1, shallow I-degree laceration: suture discontinuously with 2‐0 catgut, and no stitches will be needed in the future. It can also be sutured with 1 silk thread, and the suture is removed 2 ~ 3 days after operation.
2. For second-degree laceration: suture the vaginal wall intermittently with No.0 gut.
Surgical steps: First, put a gauze roll with a tail in the vagina to avoid the bleeding in the uterus from affecting the suture laceration. Pay attention to suture the first needle about 0.5cm above the laceration, puncture the retracted blood vessel, and avoid hematoma caused by leakage. Pay attention to the deep submucosal tissue to stop bleeding, and do not penetrate the rectal wall at the same time. Simple lacerations can be sutured continuously, and more complicated ones are best sutured intermittently.
Postoperative treatment: anal examination was performed after operation to check whether suture penetrated the rectal wall. If there is, take it out immediately and sew it again. Muscle tissue is intermittently sutured with No.0 gut thread, subcutaneous tissue and skin can be intermittently sutured together with No.4 silk thread, and the skin edge is stitched back, so that the wound is closed and easy to heal. For irregular vaginal laceration and deep laceration, in order to prevent bleeding after suture, an oily gauze roll can be placed in the vagina to stop bleeding and taken out 24 hours after delivery.
Third-degree laceration: There are many lacerations, including mucosa, muscularis, anal sphincter, superficial perineal muscle and skin mucosa in the anterior wall of rectum. Before repair, we must carefully check the laceration, find out the anatomical relationship, and then sew it according to its anatomical level. 0.5% ~ 1% procaine was given under local anesthesia before operation, and pethidine 100mg was added to relieve pain when necessary.
Cervical laceration: suture will be chosen to stop bleeding. If the cervical laceration is serious, the lower part of the uterus should be examined, except for uterine rupture. (Note: All lacerations will be sutured, so it is convenient to expose them just after delivery. )
Treatment: If there is semilunar or annular necrotic tissue in the cervix, the inner and outer edges of the stump should be sutured or sutured with 0 or 1 catgut. Antibiotics are given after the operation to prevent infection.
Suture operation of cervical laceration: use two oval pliers to clamp both sides of the cervical laceration and pull it outward to fully expose the top of the laceration, and intermittently sew the whole cervical layer with 0 or 1 catgut thread, with the first needle exceeding the top of the laceration by 0.5cm and the last needle being about 0.5cm away from the edge of the cervix to avoid narrowing after cervical retraction.
Uterine laceration: On the one hand, doctors use uterine contraction drugs to promote uterine contraction, but they also need to pay attention to whether internal bleeding is caused by uterine rupture and deal with it as soon as possible.
Small uterine rupture can be sutured to repair the laceration, but if it is a large uterine rupture and uncontrollable uterine bleeding occurs, hysterectomy and tubal ligation can be performed at the same time. Intrafascial hysterectomy is recommended; Avoid damaging bladder and ureter; You can sew or clamp the uterine incision first to avoid excessive blood loss; Indwelling vaginal drainage tube to prevent hematoma formation and infection, and observe the bleeding situation.
At the same time, the soft birth canal hematoma was cut, the hematocele was removed, and the bleeding was stopped and sutured. Rubber drainage can be placed when necessary, and vaginal tamponade is also effective. If the hematoma is still enlarged and uncontrollable, interventional vascular embolization should be considered.
Polizel's therapy
1. Wash vulva with 1: 1000 benzalkonium bromide, then scrub with 75% alcohol twice a day to keep vulva clean. If the stool overflows, clean and disinfect the vulva immediately.
2. Eat a slag-free diet 3-5 days after operation.
3. Give 0.5ml of opium tincture three times a day, or use 2ml of compound camphor tincture three times a day to control stool within 5 days, which is beneficial to wound healing.
How to prevent soft birth canal injury
1, do a good job in publicity, education and preventive health care.
Encourage planned women to participate in physical exercise and physical activities before pregnancy, enhance skin and muscle elasticity and prevent obesity.
Strengthen prenatal health education and delivery knowledge education.
2, do a good job of production inspection
Strengthen perinatal health care, do a good job in prenatal examination, actively prevent and treat complications such as pregnancy-induced hypertension, and achieve early detection and early treatment. If the fetus is found to be large during pregnancy or has given birth to a huge baby in the past, pregnant women should check this situation. If you are a pregnant woman with diabetes, you should actively treat her. After 36 weeks of pregnancy, you should choose induced labor or cesarean section according to fetal maturity, placental function examination and diabetes control.
Pregnant women with normal pelvis, estimated fetal weight below 4000g and conditional natural delivery should be instructed to do anal lifting exercise 1 ~ 2 weeks before the expected date of delivery, 1 ~ 2 times, 5 ~ 10 min each time.
3. Do a good job in maternal cooperation and guidance.
We should change the traditional purely biomedical factors that focus on prenatal examination and delivery, and incorporate psychological consultation, guidance and maternal knowledge popularization into obstetric work procedures to help pregnant women eliminate bad psychology such as fear, anxiety and impatience, wait for delivery in the best psychological state, and change passive initiative into natural, normal and healthy delivery.
Steps:
First of all, we should have extensive communication with the parturient, exchange ideas with each other, and eliminate ideological worries and nervousness: instruct the parturient how to use abdominal pressure reasonably during delivery, how to cooperate with the midwife, and reduce the damage to the birth canal.
In the first stage of labor, instruct the lying-in woman to take a free position, and don't hold her breath downward during contractions. Encourage lying-in women to eat light and digestible food to maintain vigorous energy and physical strength.
In the second stage of labor, because the pain is aggravated and the mood is easy to fluctuate, the midwife should be patient and comfort, do a good job of guidance, guide the parturient to take a deep breath first during the contraction, and then hold her breath twice with abdominal pressure, giving encouragement and comfort at intervals to enhance confidence; When the fetal head bulges, instruct the parturient to open her mouth and exhale during contraction, and do not use abdominal pressure. During the interval of uterine contraction, the parturient can gently hold her breath, so that the fetal head and uterine contraction can be delivered slowly, which can avoid or reduce the injury of the soft birth canal.
Laceration of soft birth canal
Soft birth canal laceration is very common in production, but it is not necessarily due to production. So what is the cause of soft birth canal laceration?
The main causes of laceration of soft birth canal are excessive uterine contraction, too fast labor, too large fetus, failure to protect perineum during delivery, or improper vaginal delivery, such as prenatal delivery or fetal delivery, which can all cause laceration of perineum, vagina and cervix. In severe cases, it can reach the vaginal vault, lower uterine segment or perineum, and it can also cause excessive blood loss, leading to aggravated laceration.
In addition, too strong uterine contraction will lead to too fast progress of labor, too large fetus, failure to protect perineum or vagina during delivery, and improper midwifery operation, all of which can cause perineum, vagina and cervix laceration. Premature episiotomy can also lead to excessive blood loss.