The study found that since the 1990s, the rate of caesarean section in the mainland has skyrocketed. Although caesarean section does reduce maternal mortality and perinatal mortality, the incidence of caesarean complications is gradually increasing as more pregnant women choose caesarean section.
A scarring pregnancy by caesarean section is a long-term complication of caesarean section. Although rare, it also increases with the increase in caesarean section rates.
Definition of pregnancy by caesarean section scarring
Caesarean section scar pregnancy (CSP) is a special type of pregnancy in which a fertilized egg implants at the scar of the uterine incision of the last caesarean section. However, this definition has a time limit, and it can only be called a cesarean section scar pregnancy if it occurs during the first trimester of pregnancy within 12 weeks of a woman's pregnancy.
Caesarean section scars are defined as low echoes or high echo lines of the anterior inferior wall of the uterus, which are caused by a previous caesarean section. Caesarean section scars consist of two parts: obvious defects and scar tissue connected to the muscle layer of the uterus.
Type of caesarean section scar pregnancy
Endogenous type
Implantation occurs at the site of scarring and grows towards the isthmus of the cervix or intrauterine cavity, making it possible to achieve a viable pregnancy, but at risk of placental implantation and heavy bleeding.
Exogenous
The gestational sac is deeply embedded in the scar tissue and the surrounding uterine muscle layer and grows toward the bladder. A layer of uterine muscle can be seen between the gestational sac and the bladder in the early stages, but as pregnancy progresses, the gestational sac thins and eventually disappears as the space expands.
Therefore, exogenous CSP carries the risk of uterine rupture and intraperitoneal bleeding.
Magnetic resonance sagittal diagram at 15 weeks' gestation during caesarean section scarring, showing gestational sac growing towards the bladder. U: uterus, P: placenta, B: bladder.
epidemiology
According to the latest overview of nice guidelines, the incidence of ectopic pregnancies is 11 per 1000 pregnancies. Because of the lack of effective treatment, the presence of scar tissue during pregnancy is an obstetric nightmare.
The prevalence of scar pregnancies by caesarean section is reported to be 1/2200 to 1/1800, and the prevalence is increasing due to the implementation of more CSs (caesarean sections).
Causes of scar pregnancy by caesarean section
The specific cause of a scar pregnancy by caesarean section is unclear and may be related to endometrial damage, poor scar healing, excessive scarring, or inflammatory response after caesarean section.
Symptoms of a scarring pregnancy by caesarean section
Most caesarean section scar ectopic pregnancies are asymptomatic.
Some patients may experience symptoms such as vaginal bleeding and mild abdominal pain in the lower abdomen.
A small number of patients will have vaginal bleeding, severe abdominal pain, and shock symptoms such as increased heart rate, decreased blood pressure, and pallor due to uterine rupture.
Diagnosis of scarring pregnancy by caesarean section
Diagnosis of CSP (Caesarean Section Scar Pregnancy) is a daunting task that requires experience. The main diagnostic tool is ultrasonography. In addition, there are mriography, serum human chorionic gonadotropin (β-hCG) tests, and blood routine tests.
The criteria for identifying CSP in the first trimester are:
1. Vaginal ultrasound shows empty uterine cavity, clear endometrium, empty cervical canal;
2. Detection of gestational sacs embedded in caesarean section scars in the anterior lower segment of the uterus;
3. Lack of uterine muscle layer or thin (
MRI pelvic sagittal image showing an empty gestational sac located in the lower segment of the uterus, partially attached to a previous caesarean section (blue arrow) within the endometrium (yellow arrow). Thin layer of uterine muscles (red arrows) between the sac and the bladder wall. The bladder wall is intact and smooth (green arrow).
4. Color Doppler shows that perycapsular blood flow has low impedance (pulsation
5. Lesions of the adnexal appendages should be excluded and fluid should not be detected in douglas sacs unless there is heavy bleeding or uterine rupture.
Treatment of scar pregnancy by caesarean section
Appropriate individualized treatment options should be selected based on gestational age and the patient's specific circumstances. The key to treatment is the early termination of pregnancy using a multidisciplinary approach.
The goal of treatment is to remove the gestational sac, prevent bleeding, and maintain the patient's fertility and life safety.
There are two main types of treatment: medication and surgery.
Pharmacotherapy is a multi-choice injection of methotrexate (MTX) that can be injected intracapsularly, topically, systemically, or intramuscularly.
Surgical treatment may be assorted hysteroscopic aspiration and curettage, laparoscopic or open scar resection, transvaginal pregnancy removal, uterine scar repair, and uterine artery embolization.
After the patient with caesarean section scar pregnancy is stable, attention should be paid to appropriate exercise, reasonable and balanced diet, regular work and rest, and personal hygiene.
In addition, the patient's family should pay more attention to the patient's emotional and psychological conditions, and if the situation is not right, it is recommended to give timely communication and guidance.