Uterine fibroids are the most common pelvic tumor in women, and they occur in the reproductive age. The incidence of uterine fibroids in pregnancy is about 5 %. It accounts for 0.3~7.2 % of pregnancies, and the incidence of uterine fibroids in pregnancy is on the rise with the delay of childbearing age and the popularity of ultrasound diagnosis. The diagnosis of uterine fibroids in pregnancy is usually not clinically symptomatic, and the signs are mainly protruding masses palpable on the uterine wall. During pregnancy, fibroids can increase in size and become easily palpable, but they can also become softer and flatter, making them less palpable on palpation. Therefore, it is common to miss the diagnosis of fibroids in pregnancy.
At present, ultrasound diagnosis is simple and easy, and has high accuracy in the diagnosis of fibroids, and can also dynamically observe the changes of fibroids during pregnancy, which is an effective means to diagnose fibroids. B ultrasound should be performed in all of the following cases to avoid missed diagnosis of fibroids in pregnancy:
(1) asymmetric enlargement of the uterus; (2) pelvic mass on one side; (3) uterine enlargement beyond the menopause month; (4) history of abnormal vaginal bleeding or poor obstetric history.
The size, location and number of fibroids and their relationship with the placenta should be noted during the B-ultrasound examination.
Differential diagnosis of uterine fibroids in pregnancy.
①Subplasmaline fibroids should be differentiated from ovarian tumors, uterine malformations, and horn pregnancy.
(2) Local contraction of uterus: the mass disappears after the contraction is relieved; (3) Fetal limb: fibroids are characterized by fixed position and are more clearly palpated when the uterus is contracted, while fetal limbs can be moved and are not palpated when the uterus is contracted.
④When pregnancy is combined with red degeneration of uterine fibroids, it is important to differentiate them from ovarian tumor torsion and acute appendicitis.
The effect of pregnancy on uterine fibroids (a) change in the position of fibroids: as the uterus increases in pregnancy, the position of fibroids changes accordingly, and they can be displaced up and down or left and right with the extension of the uterine wall.
(2) Increase in the size of fibroids: due to the high level of estrogen and progesterone during pregnancy and the increased blood supply to the uterus, fibroid cells become hypertrophic and edematous, making fibroids larger and softer, sometimes becoming flat.
(3) Myoma degeneration and necrosis: Due to the increase of hormone level, mechanical compression and poor blood circulation in the enlarged myoma, it may cause myoma vitreous degeneration, mucous degeneration, fatty degeneration, degenerative degeneration and even hemorrhagic necrosis, but the red degeneration showing hemorrhagic necrosis is more common.
(d) Tendon torsion: Tendon torsion of subplasmalemma is not common, but its incidence is significantly higher in pregnancy than in other periods.
The effect of uterine fibroids on pregnancy (a) infertility: whether the fibroid affects conception is related to its growth site, for example, fibroids in the horn of the uterus can compress the interstitial part of the fallopian tube and prevent the sperm from meeting the egg, resulting in infertility.
(2) Miscarriage and preterm delivery: The incidence of spontaneous miscarriage in combined pregnancy with fibroids is 2~3 times higher than that without fibroids, reaching 20%~30%, especially in submucosal fibroids, which deform the uterine cavity and infect the endometrium, which is not conducive to fertilization of the egg, and even if it does, miscarriage occurs due to insufficient blood supply to the endometrium; larger interstitial fibroids are also prone to miscarriage or preterm delivery due to mechanical compression and deformation of the uterine cavity.
(3) Abnormal fetal position, fetal deformation and FGR: Due to the mechanical obstruction of myoma, the fetal movement is restricted, which may cause abnormal fetal position. In addition, the fetal deformation and FGR may occasionally be caused by the compression of myoma.
(4) Placental abnormalities: Myoma may cause meconium failure in the adjacent area, which may interfere with the implantation of the egg and lead to placenta praevia or early abruption of the placenta, which may prevent the placenta from expelling itself during delivery.
（If the fibroids are located in the body of the uterus, they can be squeezed out of the pelvic cavity as the uterus increases in size and will not affect delivery; however, the fibroids in the lower part of the uterus or the cervical part of the uterus stay in the pelvic cavity and affect the articulation of the previa and pelvic entry, resulting in high previa and abnormal fetal position and preventing normal delivery. During delivery, myomas make the uterus contraction malfunction, causing primary or secondary uterine contraction weakness, resulting in prolonged labor.
(f) Postpartum hemorrhage: The presence of fibroids hinders uterine contraction, especially when there are submucosal fibroids, or when the placenta is attached to the surface of fibroids, placental adhesions or even implantation may occur, and postpartum hemorrhage increases significantly.
(vii) Uterine torsion: If there is a fibroid on one side of the uterus, with the softening of the cervix of pregnancy, uterine torsion may occur, resulting in sudden and severe abdominal pain, and in severe cases, shock may occur.
(H) puerperal infection: poor uterine regeneration, poor drainage of malignant fluid or prolapse of submucosal fibroids can easily induce puerperal infection.
Management of pregnancy combined with uterine fibroids.
(I) Non-pregnancy: Pre-pregnancy surgery is recommended if the following conditions exist
1. Submucosal fibroids may prevent embryonic implantation and may lead to early miscarriage . Therefore, if submucosal fibroids are diagnosed before pregnancy, it is recommended to remove them even if they are small.
2.For those who are under 40 years old and have a history of multiple miscarriages or long-term infertility combined with fibroids, myomectomy is feasible, which can improve the fertility function and prevent various complications of fibroids after pregnancy.
(3) Large interstitial fibroids (>4 cm in diameter), especially those bulging into the uterine cavity, may deform the uterine cavity, so myomectomy is also recommended before pregnancy.
(b) Asymptomatic pregnancy does not require special treatment and regular prenatal checkups are sufficient. If red degeneration of fibroids occurs, treat accordingly.
Myomectomy in pregnancy: In the early 19th century, hysterectomy was usually performed for uterine fibroids in pregnancy, but due to high postoperative complications and mortality, myomectomy was gradually adopted instead of hysterectomy, but due to:
(1) the blood supply is rich during pregnancy, so bleeding is active during myoma removal, and it is difficult to stop bleeding; (2) the fibroids are congested and soft during pregnancy, and the borders are unclear, so it is difficult to identify the exact location of the fibroids during surgery; (3) there is a possibility of miscarriage and preterm delivery; (4) the fibroids tend to shrink gradually after delivery, so surgery is not always necessary.
Therefore, myomectomy is not recommended during pregnancy except for the following cases.
(1) myoma is growing rapidly and its presence has become an obstacle to continue pregnancy; (2) myoma is the cause of multiple previous miscarriages; (3) myoma twist, myoma entrapment or uterine torsion resulting in acute abdominal pain. In addition, surgery should be considered if the myoma is red and degenerative and conservative treatment is not effective; (4) severe symptoms of myoma pressing on adjacent organs.
(3) During delivery.
All pregnancies with fibroids should be admitted to hospital for delivery. Regardless of vaginal delivery or cesarean delivery, active preparations should be made, such as blood preparation, reasonable arrangement of operating staff and operation time, prevention and treatment of postpartum bleeding, and hysterectomy if necessary.
Uterine fibroids in pregnancy are not absolute indications for cesarean delivery, but are determined by the size of the tumor and whether it obstructs the birth canal. The possibility of obstructed labor can be predicted by B ultrasound and abdominal palpation in late pregnancy, and the appropriate mode of delivery can be chosen.
(1) Vaginal delivery: if the tumor is less than 6 cm in diameter, does not obstruct the fetal delivery through the vagina, and there are no other obstetric complications and high-risk factors, vaginal delivery can be attempted.
(2) Cesarean section: if the following conditions exist, cesarean section should be considered: (1) if the placenta is attached to the surface of the fibroid, which is prone to placental adhesion or even implantation and may cause postpartum hemorrhage or require hysterectomy; (2) if the fibroid is located in the lower part of the uterus or the cervix, which may obstruct the birth canal or be complicated by placenta praevia or fetal malposition; (3) if the fibroid has been removed or combined with a history of infertility for many years or a precious fetus.
(3) Treatment of uterine fibroids during cesarean delivery: There are two views on whether to perform surgical treatment of fibroids during cesarean delivery. One view is that surgical treatment is not advocated: except for subplasmic fibroids with tissues, fibroids that can be easily removed near the uterine incision of cesarean delivery or subplasmic fibroids that are not too large, generally do not perform myomectomy at the same time of cesarean delivery. If removal is necessary, it should be done after the return of menstruation after delivery. The reasons for this are:
① pregnancy, the myometrial blood supply is rich, easy to bleed during surgery, and increase the possibility of postpartum bleeding and infection; ② after delivery of the fetus, the uterus contraction deformation, myoma position changes and the surrounding boundary is unclear, increasing the difficulty of surgery; ③ postpartum myoma can be reduced.
Another opinion is that, compared with single cesarean section, the bleeding volume of uterine fibroids removed at the same time of cesarean section is not much increased, and the difficulty of surgery is not significantly increased, but if the fibroids are left untreated, it may affect the uterine contraction and increase the chance of pelvic infection. It is believed that myomectomy can be performed even for large fibroids > 5 cm in diameter, and that this will prevent postoperative reoperation in 90% of patients with solitary fibroids and in half of patients with multiple fibroids.
What are the following conditions in which myomectomy can be performed at the same time as cesarean delivery:
(1) fibroids with a tipped or mostly subplasmic protrusion; (2) intermural or submucosal fibroids >4 cm in diameter and close to the uterine incision.
Simultaneous myomectomy should be avoided in the following cases.
① those with postpartum hemorrhage; ② those with serious comorbidities or complications that cannot tolerate prolonged surgery; ③ those with fibroids located in the uterine horn and parametrium with rich blood supply around them, the bleeding volume during cesarean section with simultaneous myomectomy is significantly higher than that of simple cesarean section, and in a few cases hysterectomy has to be performed due to excessive blood loss; ④ fibroids with a diameter of less than 4 cm tend to shrink gradually after delivery, so it is not necessary to perform resection to avoid increasing the operation time and surgical trauma. It is not necessary to perform resection to avoid increasing the operation time and surgical trauma.
For those who intend to perform myomectomy at the same time of cesarean section, the following preoperative preparations should be made:
①Prepare adequate blood supply for emergency; ②The surgeon must be skilled to perform internal iliac artery or uterine artery ligation and total hysterectomy.
Intraoperative precautions:
(1) Generally, the cesarean section is performed first, except for submucosal myoma which is removed through the uterine cavity, the rest should be sutured to close the cesarean incision first, and then the myoma is removed; (2) oxytocin is used to close the myoma around and at the base of the removed myoma, and then the myoma is removed; (3) the myoma is separated from the uterine wall after finding the boundary between the myoma and the uterine wall, and the method of ligating the peritoneal vessels while separating can be adopted to gradually peel out the myoma to reduce traumatic bleeding.
(d) Red degeneration of fibroids in pregnancy or puerperium: Red degeneration of fibroids occurs in the middle and late stages of pregnancy or puerperium, manifested as acute severe abdominal pain, fever, enlarged fibroids with pressure pain and elevated white blood cells. It is important to differentiate it from other acute abdominal conditions such as ovarian tumor torsion in pregnancy, subplasma myoma torsion, and acute appendicitis. After the diagnosis is confirmed, conservative treatment should be given first, including:
(1) bed rest; (2) adequate intravenous rehydration and general supportive treatment; (3) appropriate sedation and analgesics; (4) placement of ice packs on the lower abdomen; (5) treatment with fetal preservation if there are contractions; and (6) antibiotics to prevent infection.
Most of the symptoms can be gradually relieved after conservative treatment and can be recovered in a week or so, so that the pregnancy can continue. However, if conservative treatment fails, removal of the degenerated myoma can be considered. If the intraoperative bleeding is not excessive, the pregnancy can continue until full term. If excessive intraoperative bleeding is found, termination of pregnancy or hysterectomy should be considered.