RESEARCH LETTER Prenatal serum screening markers may not require adjustment in former smokers Geralyn Lambert-Messerlian* and Glenn E. Palomaki Department of Pathology and Laboratory Medicine, Women and Infants Hospital and Alpert Medical School of Brown University, Providence, RI, USA *Correspondence to: Geralyn Lambert-Messerlian. E-mail: gmesserl@wihri.org Funding sources: None Conflicts of interest: Dr. Messerlian has received grant and travel support from Ansh Labs (Webster, TX). Dr. Palomaki has received grant, service and consulting fees through contracts between Women and Infants Hospital and Beckman Coulter (Chaska, MN), Ansh Labs (Webster, TX), PerkinElmer (Waltham, MA) and LabCorp (Burlington, NC). Cigarette smoking has been shown to have a significant impact on maternal serum markers used in prenatal screening. Smokers, on average, have higher second trimester maternal serum alpha-fetoprotein (AFP) and inhibin A (inhA) levels, and lower unconjugated estriol (uE3) and beta-human chorionic gonadotrophin (hCG) levels. 1–5 The first trimester serum markers, pregnancy-associated plasma protein-A (PAPP-A) and hCG are also reduced in smokers. 3,5–7 Adjusting serum marker levels for smoking status has proven to be helpful in avoiding high screen positive rates, especially for trisomy 18 when using first trimester or integrated testing. 8 Prenatal screening requisition slips are occasionally received in the laboratory with handwritten notes from the practitioners. Some inform the laboratory that the patient has recently quit smoking cigarettes. Our protocol routinely treats these patients as non-smokers for the purposes of interpreting and reporting results, but no evidence for this action is available. Our objective was to conduct a retrospective examination of prenatal screening records to determine whether serum screening marker levels should be adjusted in former smokers. All first and second trimester screening requisitions received at Women and Infants Hospital in 2014 were included. The clinical database included identification of smokers and non- smokers. Original requisition slips were reviewed to find women who reported being a former smoker, and this information was added to the database. First trimester PAPP-A and hCG had been measured upon sample receipt using a manual enzyme-linked immunosorbent assay (Ansh Labs, Webster, TX) and an automated chemiluminescent method on the DxI instrument (Beckman Coulter, Inc., Chaska, MN), respectively. Second trimester AFP, uE3, hCG and inhibin A were also measured on the DxI. Demographic data on gestational age (by LMP or ultrasound), maternal weight, race and diabetic status were used in calculation of marker multiples of the median (MoM) values according to published methods using Alpha software (Logical Medical Systems, London, UK). This study was considered exempt from review by the Institutional Review Board for Human Studies at Women and Infants Hospital. Serum marker levels were expressed as MoM and were adjusted for maternal weight, race, presence of insulin- dependent diabetes and for changes known to be associated with in vitro fertilization. For the purposes of this analysis, results were not adjusted for smoking status. We then compared MoM levels between smokers, non-smokers and those who were former cigarette smokers. The analyses focused on the first trimester PAPP-A and second trimester hCG and inhA. Cigarette smoking has the largest impact on these analyte levels, and these analytes have the largest number of observations available for analysis (e.g. first trimester hCG measurements are uncommon in our screening program). The expected effect for the other analytes is much smaller (e.g. reduction of uE3 levels of 4% among smokers). 8 The overall median MoM levels were set to 1.00 by dividing each patient MoM by the observed median MoM for all patients in the clinical database (1.01, 1.03 and 1.01, for PAPP-A, hCG and InhA, respectively). In 2014, there were 10 843 screening records from patients with a singleton pregnancy. Of these, 717 (6.6%) had only AFP measurements for open neural tube defect screening, and another 725 (6.7%) had no information recorded for smoking status. All were removed, with the remaining 9392 records subject to analysis. Overall, 8765 (93.3%) were non- smokers, 555 (5.9%) reported smoking cigarettes and 69 (0.7%) reported that they had stopped smoking cigarettes. Among this latter group of women, 31 (45%) reported being ‘former’ smokers or had ‘quit’ smoking, with no further details. Another 35 reported quitting within the last 2 months before the initial sample was tested, and the final three women reported quitting more than 2 months before the initial sample was tested. Forty-four records were from women having Prenatal Diagnosis 2015, 35, 1371–1373 © 2015 John Wiley & Sons, Ltd. DOI: 10.1002/pd.4695