Uterine fibroids are the most common benign tumors of the reproductive system in women of childbearing age, with an incidence of 20% to 50% in women of childbearing age. Fibroids may cause changes in the morphology of the cervix, uterine cavity and fallopian tube opening and affect the endometrial blood supply, leading to infertility or miscarriage. Fibroids may also cause abnormal contractions of the uterus, which may affect sperm transport and embryo implantation, and may increase the likelihood of miscarriage.
Fibroids have been reported to be an independent factor in infertility in 1% to 3% of women with infertility; they account for 7% of the causes of recurrent spontaneous abortions. Some literature suggests that myomectomy may be helpful in infertile women with fibroids who have not become pregnant after 1 year of infertility-related treatment. Different types of fibroids will have different effects on pregnancy: submucosal fibroids will reduce pregnancy and live birth rates because they affect the uterine cavity area and blood supply; interstitial fibroids will adversely affect fertility; and subplasmalemma will not affect infertility or miscarriage. The literature reports that different sites of fibroids also have different effects on pregnancy, with anterior and posterior wall fibroids having a smaller effect on pregnancy rates compared to other sites of fibroids. The effect of fibroid size on postoperative pregnancy is inconclusive, with some reports in the literature suggesting no effect; it has also been reported that the mean diameter of fibroids ≤10 cm was significantly larger in the postoperative pregnancy group than in the non-pregnancy group.
Combined pregnancy with uterine fibroids is considered a high-risk pregnancy category. Fibroids may increase rapidly in early pregnancy and may affect embryonic development or even cause miscarriage; the uterus is rich in blood supply during pregnancy and fibroids are prone to complications such as red degeneration and infection; late pregnancy mainly affects fetal orientation and mode of delivery. However, fear of pregnancy complications should not be used as a guideline for fibroid debridement surgery unless the patient has a history of fibroid-related pregnancy complications (Class III evidence). Moreover, the need for surgical treatment should not be based solely on the size of the fibroids. In particular, patients with a history of infertility need to apply ultrasound, MRI, and hysteroscopy to examine in detail the type, location, size, relationship to the endothelium, and distance from the plasma membrane of the myoma. Once diagnosed, resection of submucosal myomas is recommended (II-2A). Interstitial myomas that do not affect the uterine cavity should be fully evaluated and the pros and cons related to surgery should be communicated with the patient, and the principles of each individual treatment should be followed (III-C).
Effect of various different treatments on postoperative pregnancy in uterine fibroids
The main treatment modalities for uterine fibroids with preservation of the uterus include transabdominal myomectomy, laparoscopic myomectomy, hysteroscopic myomectomy, and robotic myomectomy. In addition, uterine artery interventional embolization and high intensity focused ultrasound are also effective treatment modalities.
Transabdominal myomectomy
is the most traditional and basic procedure. Its advantages include good surgical field of view, relatively simple operation, and complete removal of fibroids; less difficult and more secure intraoperative suturing under direct vision; and significant advantages in the treatment of multiple fibroids, larger fibroids, and fibroids in special locations. However, transabdominal surgery has disadvantages such as high intraoperative bleeding, strong postoperative discomfort, high rate of postoperative infection, long hospital stay, and easy formation of postoperative pelvic adhesions, all of which may have an impact on the postoperative pregnancy rate.
The literature reports postoperative pregnancy in 9 of 13 patients with fertility requirements treated with open myomectomy, and the mean time to postoperative pregnancy was 11.3 (5-19) months from the previous myomectomy. In another study, 220 patients undergoing open myomectomy were followed up, of whom 124 had a desire to conceive and 54 (43.5%) were successfully conceived after surgery.
Laparoscopic myomectomy
It is the most used treatment for uterine fibroids at present. It is a minimally invasive surgery with less trauma, faster postoperative recovery and less postoperative pain; laparoscopic myomectomy facilitates exposure of the pelvic cavity to reduce damage to surrounding organs, and the incidence of postoperative pelvic adhesions is significantly reduced compared with open myomectomy. However, laparoscopic surgery takes a little longer, requires more skill from the operator, and is difficult to perform with microscopic suturing; and it is difficult to detect small fibroids present between the muscle walls.
Kubinova et al. followed up 170 patients who underwent laparoscopic myomectomy for conception within 2 years after the operation. 63.5% (108/170) of the pregnancies occurred after the operation, and 34% of the pelvic adhesions were found after 2 laparoscopic examinations. Single-port laparoscopy is a minimally innovative technique that has emerged in recent years based on traditional laparoscopy. Single-port laparoscopy, as the name suggests, is more minimally invasive in appearance and has been reported in the literature to be indicated for the debulking of less than five uterine fibroids. The results of another prospective clinical study suggest comparable postoperative pregnancy and full-term delivery rates compared to conventional laparoscopy.
Hysteroscopic myomectomy
It is mainly applied to submucosal fibroids or interstitial fibroids protruding into the submucosa, and there are limitations on the number and size of fibroids, as well as on whether they have a tip and the width of the tip. Compared with open and laparoscopic myomectomy, hysteroscopic myomectomy is less invasive and has a lower rate of postoperative pelvic adhesions because it avoids intra-pelvic manipulation. However, the surgical field of view is significantly reduced, making the procedure relatively more difficult.
In the case of larger fibroids, they need to be removed in small pieces or even in separate operations. Ahdad et al. reported a 33.8% postoperative pregnancy rate in patients undergoing hysteroscopic myomectomy. Hysteroscopic myomectomy has limitations in its surgical indications, with hysteroscopic myomectomy favoring pregnancy for type 0 and type I submucosal fibroids and a non-significant difference for type II submucosal fibroids.
Robot-assisted myomectomy
It is a new procedure carried out in recent years, and there is little relevant literature in China. Some foreign literature reported a low incidence of postoperative pelvic adhesions and a postoperative pregnancy rate comparable to that of conventional lumpectomy. 1 case of uterine rupture occurred in 127 postoperative pregnancies, a rate comparable to that reported for other surgical approaches. A simple comparison between robotic-assisted myomectomy and laparoscopic myomectomy has also been published, resulting in significantly less postoperative day 1 drainage in the robotic surgery than in the laparoscopic group, but a longer operative time than in the laparoscopic group.
Precautions during myomectomy
(1) The direction of uterine incision should be chosen to facilitate suturing. The inner ring, outer longitudinal and middle of the myometrium are intertwined, and the direction of incision should be chosen to facilitate suturing.
(2) Use monopolar electrodes to cut the myometrial tissue and avoid too much electrocoagulation to stop bleeding; too much electrocoagulation may lead to postoperative tissue liquefaction and dead cavity formation.
(3) Myometrial bleeding mainly relies on myometrial contraction to compress the spiral artery to stop bleeding, but care should be taken not to suture too tightly and densely to affect postoperative blood supply and cause tissue necrosis.
(4) The uterine incision should be closed neatly without leaving a dead cavity, and deep myomas or myomas in special areas should be sutured in layers to avoid penetrating the uterine cavity as much as possible.
(5) Maintain the normal shape of the uterus and minimize the length of the uterine incision while ensuring a smooth operation.
Uterine artery intervention embolization (UAE)
The principle of UAE for uterine fibroids is to block the arterial blood supply to the fibroids by embolization of the uterine artery, thereby causing them to shrink and necrosis. However, since 30% to 50% of the blood supply to the ovaries also comes from the ovarian branch of the uterine artery, interventional embolization of the uterine artery may theoretically alter the blood supply to the ovaries and affect their function. Also the pelvic radiation during the procedure has an effect on ovarian function.
Tropeano et al. found no significant changes in estrogen levels in 36 patients who underwent uterine artery interventional embolization for uterine fibroids at a 5-year follow-up. It has also been reported in the literature that patients can have menopause-related symptoms after uterine artery interventional embolization, but the difference is not statistically significant when compared with other procedures.
In a follow-up of 105 patients undergoing uterine artery interventional embolization by Bonduki et al, 15 patients had successful postoperative pregnancies, including 2 spontaneous abortions and 14 successful deliveries (1 of which was a twin), with a mean pregnancy duration of 23.8 months (5-54 months) postoperatively. gupta et al reported a slightly lower pregnancy rate after uterine artery interventional embolization than after myoma debulking, with no statistically significant differences in postoperative complications, etc. The difference was not statistically significant, but the rate of uterine artery interventional embolization for uterine fibroids requiring surgical intervention was higher 2 to 5 years after surgery.
High-intensity focused ultrasound
It is a non-invasive treatment technique that has been gradually applied in clinical practice in recent years, mainly for the treatment of benign and malignant solid tumors, and has also achieved certain results in the treatment of uterine fibroids, because it can effectively destroy tumor tissues while avoiding damage to the path that ultrasound passes through and normal tissues around the tumor, thus becoming a treatment modality that can achieve minimally invasive treatment.
The increase in pregnancy rate after high-intensity focused ultrasound treatment of fibroids is probably due to the reduction in the size of the uterus after treatment, which restores the morphology of the uterine cavity due to fibroids and creates conditions for the fertilized egg to implant, and the heat generated during ultrasound treatment increases the blood circulation in the uterus, which facilitates the implantation of the fertilized egg. Although the current treatment is mainly performed for patients who are reluctant to undergo surgery or have high risk of surgery, high-intensity focused ultrasound is a safe and effective modality for patients with pregnancy intention without affecting obstetric indicators such as abortion.
Of the 435 patients treated with high-intensity focused ultrasound in the literature, 24 had unplanned pregnancies 1 year after the procedure. 16 of these patients who did not have a preoperative desire to have children chose abortion, 1 chose abortion due to concerns about the effect of the treatment on the fetus, and the remaining 7 had successful full-term pregnancies, 6 of which were delivered by cesarean section due to social factors (e.g., fear of pain) and 1 due to suspected fetal distress The remaining 7 patients had full-term pregnancies, of which 6 had cesarean section due to social factors (e.g. fear of pain) and 1 had cesarean section due to suspected fetal distress (which was ruled out after surgery). In 25% of the patients treated with MRI-monitored high-intensity focused ultrasound for uterine fibroids, pregnancy was successful, and 70% of them delivered successfully.
Postoperative pregnancy interval
The interval between pregnancies after myomectomy is a key factor affecting postoperative pregnancy and pregnancy outcome. The risk of uterine rupture is relatively high due to short intervals, and although the incidence of uterine rupture is only about 0.2%, it can cause serious maternal and child complications or even death if it occurs. If the interval is too long, recurrence of infertility factors such as pelvic adhesions can affect postoperative pregnancy, and fibroids can recur. The interval time varies, with Koo et al. reporting 14 months and Michael et al. reporting (12.9±11.5) months. Kim et al. reported an average of 7.6 months for single-port laparoscopy and 10.1 months for conventional laparoscopy. Palomba et al. reported 3 months, as the myometrium had returned to normal shape by 3 months postoperatively on nuclear magnetic examination.
At present, the decision of each unit is mainly based on their own surgical technique and clinical experience combined with reports in the literature, and it is hoped that more high-level controlled clinical studies will provide more favorable evidence or clinical guidelines will be issued to regulate clinical treatment. Patients who become pregnant after myomectomy are treated as high-risk pregnancies, with regular obstetric checkups to inform of the risk of uterine rupture and to pay attention to strengthening maternal and child monitoring.
General remarks
At present, transabdominal and laparoscopic myomectomy is still the main treatment modality for patients with fibroids who are planning to get pregnant. However, transabdominal myomectomy still has an impact on postoperative pregnancy and miscarriage rates because of the tendency to form pelvic adhesions. The use of laparoscopy, especially robot-assisted laparoscopy, has further improved the postoperative pregnancy rate and reduced the miscarriage rate.
Hysteroscopy has advantages in the treatment of single, small submucosal fibroids, but the difficulty in operating the surgical field and the strict surgical guidelines limit its application. Uterine artery interventional embolization is more commonly used abroad, but is less commonly used in China in patients with pregnancy intent because of the risk of damage to ovarian function. High-intensity focused ultrasound is currently considered safe and effective for the treatment of uterine fibroids. Intraoperative management should take into full consideration the effect on postoperative pregnancy, paying attention to incision selection and suturing methods; postoperative interval of 0.5 to 1 year is appropriate.