Ovarian cancer is an abnormal growth of cells in the ovaries, the reproductive glands that produce eggs and hormones. Miscarriage, or spontaneous abortion, is the loss of a pregnancy before the 20th week of gestation. The co-occurrence of these two events is exceptionally rare, complicating only about 1 in 15,000 to 32,000 pregnancies. It is important to separate whether the cancer itself causes pregnancy loss from the risks associated with necessary medical treatments.
Is There a Direct Link Between Ovarian Cancer and Miscarriage?
For the majority of ovarian cancers, the direct physical presence of the mass does not typically cause a miscarriage. These tumors primarily grow on the surface of the ovary and are unlikely to interfere with the developing pregnancy within the uterus. A physical link is generally minimal unless the tumor grows to an extremely large size, causing severe systemic effects or significant compression of the uterus or surrounding structures.
A rare but important exception involves specific types of hormonally active tumors, such as sex cord-stromal tumors. These tumors secrete high levels of substances like estrogen, which can disrupt the delicate hormonal balance required to sustain a pregnancy.
This hormonally-driven imbalance poses an indirect risk of pregnancy loss or preterm delivery by interfering with the signals that maintain the uterine lining. However, even with these rare cancer types, the primary threat to the pregnancy often shifts to the subsequent interventions required to treat the malignancy.
How Ovarian Cancer Treatments Affect Fetal Health
The greatest risks to fetal viability and development stem from the treatments necessary to manage the mother’s cancer, referred to as iatrogenic risk. Both chemotherapy and surgery require careful timing to minimize harm to the fetus, generally based on the gestational age.
Chemotherapy is generally avoided in the first trimester, the period of organogenesis, because exposure during this time carries the highest risk of congenital defects or miscarriage. If treatment cannot be delayed, certain platinum-based agents, such as carboplatin, are often considered safer options in the second and third trimesters.
Exposure to chemotherapy later in pregnancy carries a lower risk of malformation but can still lead to complications, including intrauterine growth restriction, fetal anemia, or premature delivery. Radiation therapy is almost always avoided during pregnancy due to the severe, dose-dependent risks it poses to the fetus, such as growth disturbances and fetal death.
Major abdominal surgery, often required for staging and tumor removal, also introduces risks to the pregnancy. Surgery in the first trimester is associated with higher rates of spontaneous abortion, partly due to the pregnancy’s hormonal dependence on the corpus luteum. To reduce the risk of pregnancy loss or preterm labor, surgery is typically delayed until the second trimester, specifically between 16 and 20 weeks of gestation.
Diagnosis and Management During Pregnancy
Diagnosing ovarian cancer during pregnancy presents unique challenges because standard staging and imaging procedures must be modified to protect the fetus. Symptoms of ovarian cancer, such as abdominal bloating or pelvic pain, often overlap with normal physiological changes of pregnancy, which can lead to a delayed diagnosis. Traditional tumor markers like CA-125 are also less reliable because their levels can naturally be elevated during gestation.
Diagnostic imaging relies heavily on ultrasound and magnetic resonance imaging (MRI) without contrast, as these are considered safe for the developing fetus. Computed tomography (CT) scans, particularly those involving contrast agents, are generally avoided unless the information is absolutely necessary for immediate maternal care. This modification in diagnostic approach can limit the initial staging information available to the oncology team.
Management requires a highly specialized, multidisciplinary team, including a gynecologic oncologist, a maternal-fetal medicine specialist, and a neonatologist. The central decision involves balancing the aggressive treatment necessary for the mother’s prognosis against the goal of maximizing fetal maturity. In cases of advanced cancer diagnosed in the first trimester, the difficult discussion of pregnancy termination may be necessary to allow for immediate, aggressive treatment.
For early-stage disease, the strategy often involves conservative surgery, such as unilateral salpingo-oophorectomy, to remove the affected ovary while preserving the pregnancy. Treatment is then often deferred, or neoadjuvant chemotherapy is administered in the second and third trimesters to control the cancer until a viable delivery can occur. Delivery is frequently scheduled near 35 to 37 weeks of gestation, allowing the mother to undergo definitive staging and treatment shortly thereafter.