The definitive management of adnexal masses is surgery. However, because of the low likelihood of malignancy and acute complications associated with surgery during pregnancy, the risks of surgery frequently outweigh the benefits. Therefore, most adnexal masses in pregnancy can be managed expectantly and observed through the postpartum period. With the appropriate patient selection, adverse outcomes are not increased with conservative management [12]. Treatment should be tailored to the nature, symptoms, and clinical suspicion of the mass. Should there be a need for surgical excision, a minimally invasive approach in the early second trimester (around 14–16 weeks’ gestation) will minimize the risks of preterm labor or loss of the pregnancy.

Indications for surgery include suspicion for ovarian torsion or malignancy as suggested by history, physical examination, or sonographic features. Laparoscopic versus laparotomy approach should be individualized depending on size of mass, gestational age, suspected malignancy, and expertise of the surgeon. More extensive surgery may be indicated for ovarian malignancies. The extent of the surgery must be tailored to the clinical situation such as gestational age, desire for retention of the pregnancy, future fertility, histologic cell type, and extent of the disease. Some settings may be managed via minimally invasive surgery, while others might require a vertical skin incision, surgical staging, and cytoreduction [13].

The management of ovarian torsion is similar as that in nonpregnant patients, consisting of laparoscopic detorsion with or without ovarian cystectomy or oophorectomy. During the third trimester, the size of the gravid uterus may preclude a minimally invasive approach.

Ovarian cyst rupture is usually a self-limited event. However, significant hemoperitoneum leading to hemodynamic instability requires surgical exploration and source control of the bleeding.

Generally, a vaginal delivery is not contraindicated unless the mass is fixed in the pelvis resulting in pelvic outlet obstruction. Cesarean delivery should be reserved for appropriate obstetrical indications. If a conservative approach is chosen, follow-up is appropriate 6–12 weeks after delivery, which coincides with return to pre-pregnancy physiology and resolution of most functional masses.

The state of pregnancy will often improve or eliminate endometriosis lesions as well as their associated symptoms. This is attributed to the altered hormonal environment of pregnancy that results in decidualization of the endometriotic lesions [31]. The decidualized lesions, however, may still be biologically active and produce symptoms and complications. There are reports in the literature that describe intestinal perforation [32] hemoperitoneum [33–35], uroperitoneum [36, 37], acute appendicitis [38, 39], and ruptured or infected ovarian endometrioma [40].

Endometriosis-induced complications that occur in pregnancy, albeit rare, may be associated with the expanding uterus putting traction on adhesions, increased friability of inflamed tissues, and alteration of vessel walls by decidualized lesions [40].

The rarity of these complications in pregnancy does not warrant additional monitoring or interventions in gravid women with an endometriosis history.

A retrospective populations-based study of more than 82,000 singleton pregnancies demonstrates a negative impact on pregnancy outcome in women with endometriosis. These adverse effects include an increased risk of preterm birth, preeclampsia, and abdominal delivery when compared to gravidas without endometriosis [41]. Other studies have shown that endometriosis is associated with an increased risk of spontaneous abortion, ectopic pregnancy, placenta previa, unexplained antepartum hemorrhage, postpartum hemorrhage, and preterm delivery when compared with unaffected women [42].

Other studies, however, report decreased or no change in risk of hypertensive disorders of pregnancy in gravidas with endometriosis [43, 44]. There is no known mechanism attributed to these problems and, again, closer scrutiny of pregnant women with endometriosis is not warranted [40].

The incidence of ovarian malignancy during pregnancy is generally lower than that of the general population, mainly because pregnancy occurs in a younger population [1]. Currently, the most common ovarian malignancy in pregnancy is germ cell tumors, and up to 30% of all ovarian malignancies are dysgerminomas.

Presentation for ovarian malignancy is generally similar to that of all adnexal masses with some exceptions. Sex cord-stromal tumors, although rare in pregnancy, can lead to evidence of hormonal excess (hyperestrogenism or virilization). Advanced stage ovarian malignancy may lead to small bowel obstruction.

When ovarian malignancy is suspected, the patient should be immediately referred to a gynecologic oncologist. Ovarian cancer , like most gynecologic malignancies, is surgically staged. During pregnancy, if discovered in the first trimester, the best time for surgery is after 8-10 weeks, when placental function is established and the corpus luteum has involuted, should there be a need for an oophorectomy. Surgical staging during pregnancy usually entails a unilateral salpingo-oophorectomy, omentectomy, peritoneal biopsies, lymphadenectomy, and peritoneal washings. More comprehensive staging will include the aforementioned in addition to a total abdominal hysterectomy and bilateral salpingo-oophorectomy. If the contralateral ovary appears normal, there is no need for ovarian biopsies or resection on that side. If discovered in the third trimester, more complete staging can be completed at the time of cesarean or after delivery. Decisions regarding timing and choice of surgery as well as need for adjuvant or neoadjuvant chemotherapy are made in consultation with a gynecologic oncologist. Note that pregnancy is not a contraindication to most chemotherapeutic agents, especially after the first trimester.

Prognosis mainly depends on the stage of the disease at the time of diagnosis and histologic tumor type, and is similar to that in nonpregnant patients.

Timing of delivery should be individualized. Things to consider are the stage and type of cancer, timing in pregnancy, and patient wishes regarding treatment and continuation of pregnancy especially before viability.