Outcomes of Gallstone Disease during Pregnancy: a Population- based Data Linkage Study Ibinabo Ibiebele, a,b Margaret Schnitzler, b,c Tanya Nippita, a,b,d Jane B. Ford a,b a Clinical and Population Perinatal Health Research, Kolling Institute, Northern Sydney Local Health District b Sydney Medical School Northern, University of Sydney c Department of Gastrointestinal Surgery, Royal North Shore Hospital d Department of Obstetrics and Gynaecology, Royal North Shore Hospital, Northern Sydney Local Health District, Sydney, NSW, Australia Abstract Background: Gallstone disease is a leading indication for non-obstetric abdominal surgery during pregnancy. There are limited whole population data on maternal and neonatal outcomes. This population-based study aims to describe the outcomes of gallstone disease during pregnancy in an Australian setting. Methods: Linked hospital, birth, and mortality data for all women with singleton pregnancies in New South Wales, Australia, 2001–2012 were analysed. Exposure of interest was gallstone disease (acute biliary pancreatitis, gallstones with/without cholecystitis). Outcomes including preterm birth (spontaneous and planned), readmission, morbidity and mortality (maternal and neonatal) were compared between pregnancies with and without gallstone disease. Adjusted risk ratios (aRRs) and 99% confidence intervals were estimated using modified Poisson regression and adjusted for maternal and pregnancy factors. Results: Among 1 064 089 pregnancies, 1882 (0.18%) had gallstone disease. Of these, 239 (12.7%) had an antepartum cholecystectomy and 1643 (87.3%) were managed conservatively. Of those managed conservatively, 319 (19.0%) had a postpartum cholecystectomy. Gallstone disease was associated with increased risk of preterm birth (aRR 1.3, 99% CI 1.1, 1.6), particularly planned preterm birth (aRR 1.6, 99% CI 1.2, 2.1), maternal morbidity (aRR 1.6, 99% CI 1.1, 2.3), maternal readmission (aRR 4.7, 99% CI 4.2, 5.3), and neonatal morbidity (aRR 1.4, 99% CI 1.1, 1.7). Surgery was associated with decreased risk of maternal readmission (aRR 0.4, 99% CI 0.2, 0.7). Conclusions: Gallstone disease during pregnancy was associated with adverse maternal and neonatal outcomes. Most women with gallstone disease during pregnancy are managed conservatively. Surgical management was associated with decreased risk of readmission. Keywords: pregnancy, hospitalisation, cholecystectomy, cholecystitis, morbidity. Symptomatic gallstone disease is a leading indication for emergency abdominal surgery during pregnancy along with suspected appendicitis and bowel obstruc- tion. 1,2 Pregnancy is associated with the formation of biliary sludge and gallstones as a result of the actions of oestrogen and progesterone promoting increased cholesterol secretion and biliary stasis. 3 It is estimated that 0.05%–0.8% of pregnant women have symp- tomatic gallstones. 2 Diagnosis and treatment of gallstone disease during pregnancy is challenging; balancing the risks and benefits to the mother and baby. Non-surgical man- agement is reportedly associated with high rates of symptom recurrence and the risk of disease progres- sion 2 ; while surgery carries potential risks to the mother and baby from anaesthesia and radiation exposure from medical imaging. 4 Population-based data on maternal and neonatal out- comes is important for counselling pregnant women with gallstone disease. However, given the rarity of this pregnancy complication, much of the evidence on maternal and neonatal outcomes come from reviews and meta-analyses of single centre retrospective case series and reports. 2,5,6 There are few population- based studies that have compared outcomes between pregnant and non-pregnant women; and there are no population data from an Australian context. 4 Correspondence: Ibinabo Ibiebele, Clinical and Population Perinatal Health Research, Building 52, University of Sydney at Royal North Shore Hospital, St Leonards, NSW, Australia. E-mail: Ibinabo.ibiebele@sydney.edu.au © 2017 John Wiley & Sons Ltd Paediatric and Perinatal Epidemiology, 2017, 31, 522–530 522 doi: 10.1111/ppe.12406