402 Impact of chemotherapy during pregnancy on neonatal birthweight

Abstract

This retrospective cohort study was designed to evaluate fetal growth, assessed by prenatal ultrasound and neonatal birthweight, in pregnant women receiving chemotherapy. Patients, registered by the International Network of Cancer, Infertility and Pregnancy (INCIP), treated with chemotherapy with at least two ultrasounds reported between 24 and 34 weeks of gestation were selected. Based on predefined ultrasound criteria (Delphi consensus, 2016) and birthweights, pregnancies were allocated to the following groups 1) FGR (fetal growth restriction) 2) low risk small for gestational age (SGA) (birthweight below the 10th centile, but normal ultrasound) 3) presumably FGR that did not meet all FGR criteria 4) non-FGR. Obstetric and oncological characteristics were compared between the FGR and the non-FGR group. Multivariable regression models were used to investigate the effect of the duration of chemotherapy on birthweight percentiles (reference chart Nicolaides, 2018). In total, 201 women, diagnosed with cancer between 2000 and 2020, were included. Breast cancer was most common (132, 66%) and most frequently administered regimens were anthracyclines (121, 60%), anthracyclines and taxanes (40, 19%) and platinum (35, 17%). The median birthweight percentile was 30 (range 1-100). In total, 75 pregnancies (37%) showed fetal growth abnormalities, including 43 FGR neonates (21%), additionally 10 (5%) SGA neonates and 22 neonates (8.5%) were presumably FGR. Initiation of chemotherapy prior to 20 weeks of gestation (p=0.026) and low maternal gestational weight gain (p=0.046) were risk factors for FGR, however no specific chemotherapy regimens or cancer types contributed independently. Multivariable regression revealed that the duration of chemotherapy was negatively related to birthweight percentiles (-1.064; 95%CI 2.064;-0.063; p=0.037). FGR is common in chemotherapy-exposed fetuses and the duration of chemotherapy exposure negatively impacts birthweight percentiles. Serial growth scans are recommended in this high risk population.View Large Image Figure ViewerDownload Hi-res image Download (PPT)