Objective: To determine median values of biochemical maternal serum markers during second trimester maternal screening to rule out chromosomal anomaly, Down syndrome.
Study Design: Cross sectional study.
Place and Duration of Study: Department of Chemical Pathology and Endocrinology, Armed Forces Institute of Pathology (AFIP), from Nov 2016 to May 2017.
Patients and Methods: Non-probability consecutive sampling technique was used. All healthy pregnant women with single pregnancy were included. As non-parametric statistics was used, the sample size was collected to be 155. Blood sample for serum human chorionic gonadotropin (HCG) was analyzed on random access immulite 2000, alpha-fetoprotein (AFP) was analyzed on ADVIA Centaur, unconjugated estriol (uE3) and Inhibin A measured by Enzyme-Linked Immunosorbent Assay (ELISA) method by PR 4100 Micro plate Reader.
Results: Total 155 women were enrolled in this study. Mean maternal age was 33.46 ± 2.35 years and mean maternal body weight was 54.98 ± 2.88 kg. Median value of quadruple markers, calculated from 15-18th week of gestation, was used for calculation of multiple of median (MoM) for screening of trisomy21 in this gestational age. Median values at 15 week of gestation: hCG 36650 mIU/ml, AFP 23.3 IU/ml, uE3 3.5 nmol/l, Inh A 198 ng/l, at 16 week of gestation: hCG 29050 mIU/ml, AFP 35.4 IU/ml, uE3 4.1 nmol/l, Inhibin-A 179 ng/l; at 17 week of gestation: hCG 28450 mIU/ml, AFP 36.0 IU/ml, uE3 6.7 nmol/l, Inhibin-A 175 ng/l and at 18 week of gestation:
HCG 25200 mIU/ml, AFP 38.2 IU/ml, uE3 8.2 nmol/l, Inhibin-A 190 ng/l.
Conclusion: In this study we were able to get median values of quadruple markers for regional population, which will be used in future to calculate MoM for the screening purpose of Down syndrome. It will help to rule out Down syndrome by non-invasive test and at early stage of pregnancy.
Keywords : Down syndrome, Median, Second trimester, Screening, Serum biomarker.