American Cancer Society; Centers for Disease Control and Prevention; Swiss Re; Swiss Cancer Research foundation; Swiss Cancer League; Institut National du Cancer; La Ligue Contre le Cancer; Rossy Family Foundation; US National Cancer Institute; and the Susan G Komen Foundation.

A B S T R A C T PurposeThe aim of this study was to assess the management and the obstetrical and neonatal outcomes of pregnancies complicated by cancer. Patients and MethodsIn an international collaborative setting, patients with invasive cancer diagnosed during pregnancy between 1998 and 2008 were identified. Clinical data regarding the cancer diagnosis and treatment and the obstetric and neonatal outcomes were collected and analyzed. ResultsOf 215 patients, five (2.3%) had a pregnancy that ended in a spontaneous miscarriage and 30 (14.0%) pregnancies were interrupted. Treatment was initiated during pregnancy in 122 (56.7%) patients and postpartum in 58 (27.0%) patients. The most frequently encountered cancer types were breast cancer (46%), hematologic malignancies (18%), and dermatologic malignancies (10%). The mean gestational age at delivery was 36.3 Ϯ 2.9 weeks. Delivery was induced in 71.7% of pregnancies, and 54.2% of children were born preterm. In the group of patients prenatally exposed to cytotoxic treatment, the prevalence of preterm labor was increased (11.8%; P ϭ .012). Furthermore, in this group a higher proportion of small-for-gestational-age children (birth weight below 10th percentile) was observed (24.2%; P ϭ .001). Of all neonates, 51.2% were admitted to a neonatal intensive care unit, mainly (85.2%) because of prematurity. There was no increased incidence of congenital malformations. ConclusionPregnant cancer patients should be treated in a multidisciplinary setting with access to maternal and neonatal intensive care units. Prevention of iatrogenic prematurity appears to be an important part of the treatment strategy.