Obstetric and perinatal outcomes following a diagnosis of gynecologic cancer during pregnancy

INTRODUCTION: Around 5 in 100,000 pregnancies are affected by maternal gynecologic cancer, and the incidence is increasing. We investigated if gynecologic cancer diagnosed during pregnancy influences the risk of adverse obstetric and perinatal outcomes. MATERIAL AND METHODS: This population-based matched study included singleton births registered between 1973 and 2017 in the Swedish Medical Birth Register to women without previous cancer (N = 4,481,808). Births where maternal cancer of the genital organs were diagnosed during pregnancy (n = 269) were identified, and 26,900 cancer-free comparators were matched on maternal age and year of delivery, and birth order. Adjusted conditional logistic and multinomial logistic regression were used to estimate odds ratios (OR) and relative risk ratios (RRR). RESULTS: Among the 269 women diagnosed with cancer, 196 were cervical cancer, 64 ovarian cancer and 9 other gynecologic cancer types. Maternal gynecologic cancer was associated with higher risks of preterm birth (34-36 weeks: RRR 8.7, 95 % CI 6.2-12.1; 32-33 weeks: 41.0, 26.5-63.5; <32 weeks: 34.8, 22.9-53.0) and cesarean delivery (OR 11.6, 95 % CI 9.0-15.0). Planned preterm delivery was significantly (p < 0.001) more common in cases (36.6 %) than comparator births (0.4 %), as was spontaneous preterm delivery (9.7 % vs 4.4 %, p < 0.001). A higher risk of stillbirth was observed (OR 4.4, 95 % CI 1.6-12.1) based on 4 events among cases, who were all delivered preterm. CONCLUSIONS: Gynecologic cancer during pregnancy was associated with higher risks of preterm birth and adverse preterm-related outcomes. The risks of maternal pregnancy complications and low birth weight for gestational age were similar to those of cancer-free births.