Although adnexal masses are relatively common in pregnancy, 95 to 99 percent are benign (noncancerous) and disappear on their own, according to a study published November 2019 in the Journal of Ovarian Cancer Research. In fact, ovarian cancer is “exceedingly rare” during pregnancy (occurring in less than 1 percent), according to new research published in June 2020 by F1OOO Research. Still, both the discovery of a mass and a possible suspicion of cancer can be scary for expectant parents. What does it mean for the fetus’ health? Can the pregnancy be continued? And if you’ve had ovarian cancer previously, are you still able to become pregnant? Here’s what you need to know.

Know Your Ovarian Cancer Risk

Most ovarian cancers actually start in the fallopian tubes, which serve as pathways to the uterus. Roughly 90 percent are epithelial, meaning that they originate in the cells residing on the outer lining of the ovaries. Ovarian cancers are characterized as benign, borderline (have low malignant potential), or malignant (cancerous), according to the American Cancer Society. For women without a family history of ovarian cancer, risk increases with age, and more specifically, after menopause. The average age of most ovarian cancers is about 60, says Heidi Gray, MD, associate professor of gynecologic oncology at the University of Washington in Seattle. But pregnancy in and of itself is not a risk factor, she says. In fact, previously carrying children to term before age 35 may offer extra protection against ovarian cancer, as does the use of oral contraceptives or breastfeeding, per the American Cancer Society. Most importantly, ovarian cancer during pregnancy is not commonly associated with a poorer prognosis, according to the International Network on Cancer’s infertility and pregnancy consensus guidelines, published October 2019 in the Annals of Oncology. A strong family history of ovarian cancer (or breast or colorectal cancer) increases overall ovarian cancer risk and increases the likelihood for harboring a pathogenic genetic mutation like BRCA1, or BRCA2, especially if a relative (especially mother, sister, or aunt) was diagnosed at a relatively younger age, explains Jessica Lee, MD, an assistant professor in the department of obstetrics and gynecology at University of Texas–Southwestern Medical Center in Dallas. Other risk factors include Eastern European or Ashkenazi Jewish background, and endometriosis, according to the Centers for Disease Control and Prevention (CDC). Before becoming pregnant, at-risk women are often encouraged to speak to their family practitioners or gynecologists to determine if they are candidates for genetic testing says, Dr. Lee, adding that she often recommends that her pregnant patients consider forming a care team consisting of a gynecologist, gynecologic oncologist, and maternal-fetal specialist if high-risk surveillance is required. RELATED: Ovarian Cancer: Understanding Genetic Testing

An Ovarian Cancer Diagnosis During Pregnancy

Many of the signs and symptoms of adnexal masses and ovarian cancer are nonspecific. For example, abdominal bloating, abdominal and back pain, and changes in bladder and bowel function are also associated with pregnancy, says Sanaz Memarzadeh MD, professor and gynecologic cancer surgeon at UCLA Ronald Reagan Hospital in Los Angeles. According to Dr. Memarzadeh, these masses (called functional cysts) are often a normal part of pregnancy and disappear on their own by the second trimester. Many practitioners rely on a watch-and-wait strategy that includes a follow-up ultrasound in the second trimester to see if the mass has resolved. If there is a suspicion that the mass may be cancerous, your doctor will likely refer you to a gynecologic oncologist for additional imaging (such as magnetic resonance imaging, or MRI, which can be safely used throughout pregnancy), staging, and if necessary, treatment. Women who live in more rural areas might be able to arrange initial telehealth appointments with a larger care team for some of these early decisions, notes Dr. Gray. RELATED: How Is Ovarian Cancer Diagnosed?

Why Early Detection Is Key

An advantage of earlier diagnosis is the potential to avoid unnecessary treatment and improve outcomes. Lee explains that treatment decisions are made on the basis of several factors, including the trimester of pregnancy, how quickly (or slowly) the tumor appears to be growing, if there is an indication that the tumor has spread (metastasized) beyond the ovaries, and gestation period. Sometimes, minimally invasive, laparoscopic surgery is conducted to confirm diagnosis or to remove the tumor, but won’t be performed until after 16 weeks gestation and during the second trimester, when risks are the lowest to both the mother and fetus. If debulking surgery (removing as much of the tumor as possible) is indicated, it is often delayed until after birth, says Gray. RELATED: Ovarian Cancer Survivor Stories

Is Chemotherapy Safe When You’re Pregnant?

Every decision on how to proceed is made with two factors top of mind: the health of the mother and the baby. Pregnancies that involve maternal cancer are considered high risk, and mothers may need to be admitted to and followed throughout the pregnancy within a multidisciplinary care team obstetrical unit. If the tumor cannot be completely removed by surgery, then your doctor and care team may recommend chemotherapy. Memarzedeh explains that chemotherapy can be safely administered during the second or third trimesters but if possible, might be delayed until after delivery. Decisions on timing (which also involve consultations with a maternal-fetal medicine specialist) also may affect breastfeeding (so as to avoid passing toxins in milk to the newborn). However, if ample time has passed before delivery, breastfeeding can still be considered, Mamarzedeh says. Fortunately, overall pregnancy outcomes for both the mother and fetus are similar to those seen in normal, healthy pregnancies, even when the pregnancy is high risk, according to a review published in the May 2017 issue of Best Practices & Research Clinical Obstetrics & Gynecology Journal. RELATED: A Glossary of Formal and Informal Terms Used to Describe Ovarian Cancer

Ovarian Cancer Before Pregnancy and Fertility Preservation

While it is perfectly safe to become pregnant if you’ve been diagnosed with ovarian cancer, fertility preservation strategies may be recommended. One option is to freeze eggs (cryopreservation) before starting chemotherapy and insert them by in vitro fertilization at a later time. This is associated with moderately good outcomes, says Marmazedeh, adding that about 40 percent of these women can achieve a successful pregnancy, and up to a third, successful deliveries. In some cases, ovarian tissue can be frozen and then transplanted after cancer treatment, with successful delivery rates as high as 57 percent, according to a review published in February 2020 in the journal Acta Obstetricia et Gynecologica Scandinavica. In other cases, women may be able to opt for conservative treatment — removing one ovary with the cancer and the adjacent fallopian tube removed, which still provides her with the opportunity for pregnancy after treatment. All of these decisions are individual and made in coordination with the healthcare team and the expectant parent’s partner. Ovarian cancer before or during pregnancy is relatively rare but incidence may increase as women continue to delay childbearing to older ages or as the population ages. When caught early — before or during pregnancy — the prognosis remains good for both the mother and child. The bottom line is to know your family history and be prepared to discuss it or bring it up with your healthcare practitioner, especially as you explore your options for pregnancy and birth. RELATED: How Does Ovarian Cancer Affect Your Body in the Short and Long Term?