A guide to management: Adnexal masses in pregnancy
Forego surgery in most cases until delivery—or until the risky first trimester has passed
IN THIS ARTICLE
When size alone is the problem
Some ovarian tumors are so large they seem incompatible with an advancing pregnancy. Tumors up to 20 cm in diameter have been removed intact at the time of cesarean section (FIGURE 2).18 The tumor may accommodate in shape and become less problematic as it is gradually pushed into the upper abdomen (FIGURE 3).
The ability of the peritoneal cavity to accommodate a tumor varies greatly among women. As pregnancy advances, the likelihood that a large cystic mass will rupture tends to increase. Depending on the circumstances, percutaneous aspiration7,18 or removal of a benign-appearing cystic tumor may be appropriate.
FIGURE 2 Even a very large tumor may coexist with advancing pregnancy
This benign serous cystadenoma was exteriorized at the time of cesarean section at term.
FIGURE 3 Large ovarian tumor has accommodated to the pregnancy
Laparotomy—performed at term for cesarean section and to manage this large tumor—revealed that the tumor had accommodated in shape between the enlarging pregnant uterus and the abdominal wall.
When is the best time to operate?
Surgery is generally not recommended during the first trimester.5-11 Among the reasons are the high likelihood of a corpus luteum cyst, the low likelihood of an invasive malignancy, the low risk of adnexal complications associated with observation, and the potential for pregnancy loss or teratogenicity. However, as pregnancy progresses beyond the first trimester, surgery poses other problems: Operative exposure diminishes and the need to manipulate the pregnant uterus increases.
Can surgery be delayed when a mass is detected?
Schmeler KM, Mayo-Smith WW, Peipert JF, Weitzen S, Manuel MD, Gordinier ME. Adnexal masses in pregnancy: surgery compared with observation. Obstet Gynecol. 2005;105:1098–1103.
Close observation is a reasonable alternative to operative intervention during pregnancy, unless a malignancy is suspected.
Schmeler and colleagues reviewed the cases of 59 women who had an adnexal mass larger than 5 cm in diameter detected during pregnancy, out of a total of 127,177 deliveries at a single institution between 1990 and 2003. Antepartum surgery was performed in 17 women (29%). Of these, 13 cases had ultrasonographic findings suggesting malignancy, and 4 had ovarian torsion. The remaining women were observed, with surgery delayed until the time of cesarean section or later.
Twenty-five of the 59 masses (42%) were dermoid cysts. Cancer was diagnosed in 4 patients (6.8%), and 1 patient (1.7%) had an LMP tumor. All 5 cases (100%) involving a malignancy had a suspicious US appearance and were identified during antepartum surgery, whereas only 12 patients with a benign tumor (22%) underwent surgery prior to delivery.
Surgery poses risks to the pregnancy
Elective surgery for an adnexal mass any time during pregnancy increases the risk of pregnancy loss and the likelihood of intrauterine growth restriction (IUGR) and preterm delivery.5,7,10,13,19 A 1989 study from Sweden20 defined a cohort of 5,405 women (from 720,000 births) who were known to have a nonobstetric operation while pregnant, with the following results:
- Congenital malformation and stillbirth were not increased in the women undergoing surgery
- The number of very-low- and low-birth-weight infants did rise, however—the result of both prematurity and IUGR
- Also elevated was the incidence of infants born alive but dying within 168 hours; these risks increased regardless of trimester
- No specific type of anesthesia or operation was associated with adverse reproductive outcomes, and the cause of those adverse outcomes was not determined.
Some recent data suggest that adnexal surgery during the late second or early third trimester poses the greatest risk of preterm delivery or IUGR, or both.13
Window of opportunity: early to mid- second trimester
During this time frame, elective surgery for an adnexal mass still affords some pelvic exposure without the need for significant uterine manipulation and has been associated with a lower risk of pregnancy complications.
The other window for operation is at the time of cesarean section. An elective cesarean section is sometimes performed specifically to manage a persistent adnexal mass. Among the factors that warrant consideration when contemplating this approach are the elective uterine incision (with its attendant implications for future pregnancies), the higher risks associated with cesarean delivery in general, the type of skin incision (a vertical incision is appropriate in the event of ovarian malignancy), the potential for better exposure or laparoscopy at a later date, the increased difficulty of ovarian cystectomy at the time of cesarean section, and the patient’s wishes.
The data on laparoscopy during the first and second trimesters of pregnancy indicate that it is as safe as laparotomy. A 1997 Swedish study21 identified cohorts of 2,181 women undergoing laparoscopy and 1,522 women undergoing laparotomy (from a total of 2,015,000 deliveries) between the fourth and 20th weeks of pregnancy. In both groups there was an increased risk for the infant to weigh less than 2,500 g, to be delivered before 37 weeks, and to have IUGR. There were no differences between the 2 groups for these and other adverse outcomes.
