Malignancy complicating pregnancy is fortunately rare, affecting one in 1000 to one in 1500 pregnancies. Optimal treatment involves balancing the benefit of treatment for the mother while minimizing harm to the fetus. This balance is dependent on the extent of the disease, the recommended course of treatment, and the gestational age at which treatment is considered. Both surgery and chemotherapy are generally safe in pregnancy, whereas radiation therapy is relatively contraindicated. Iatrogenic prematurity is the most common pregnancy complication, as infants are often delivered for maternal benefit. In general, however, survival does not differ from the nonpregnant population. These patients require a multidisciplinary approach for management with providers having experience in caring for these complex patients. The aim of this review was to provide an overview for obstetricians of the diagnosis and management of malignancy in pregnancyCancer diagnosed during pregnancy is uncommon, complicating between 0.02% and 0.1% of all pregnancies. Nonetheless, due to increasing age of childbearing, the incidence of cancer during pregnancy is likely to increase due to higher incidence of several age-dependent malignancies. The most common malignancies include breast cancer, cervical cancer, malignant melanoma and lymphoma. One of the key challenges in the management of cancer in pregnancy is treating the women with standard chemotherapy regimen, without compromising the safety of the developing foetus. Exposure of chemotherapy in the first trimester is associated with an increased risk of major birth defects, whereas use in the second and third trimesters is associated with intrauterine growth restriction, low birthweight and stillbirth. In this article, we review available data regarding the use of chemotherapeutic agents in pregnancy, and we summarise the neonatal outcomes, including malformations, perinatal complications and long-term follow-up. In addition, the management plan during pregnancy is also discussed.