First-trimester screening for trisomy 21 in pregnancies conceived by in vitro fertilization

Abstract

CONCEIVED BY IN VITRO FERTILIZATION SRIRAM C. PERNI, ROBIN B. KALISH, GEETA SHARMA, MERUKA GUPTA, JENNIFER E. CHO, STEPHEN T. CHASEN, Weill Medical College of Cornell University, Obstetrics & Gynecology, New York, NY OBJECTIVE: The aim of our study was to examine the effect of in vitro fertilization (IVF) on first-trimester levels of pregnancy-associated plasma protein A (PAPP-A), free beta-human chorionic gonadotrophin (b-hCG), and nuchal translucency (NT) measurements used in aneuploidy screening. STUDY DESIGN: We compared the first-trimester maternal dried whole blood specimens for PAPP-A and b-hCG of 31 singleton pregnancies conceived by IVF with 135 pregnancies conceived spontaneously. Maternal serum biochemistry analysis was performed by NTD Laboratories and was reported as multiples of the median (MoM). NT was measured using the Fetal Medicine Foundation protocol from 11-14 weeks of gestation. Pregnancies conceived by IVF were matched with four spontaneous conception controls. Subgroups were stratified based on gestational age. Free b-hCG, PAPP-A, and NT levels were compared between the IVF and control groups using the Mann-Whitney U statistical test. A P value < 0.05 was considered statistically significant. RESULTS: PAPP-A levels were 6.6% lower and free b-hCG levels were 2.8% higher in pregnancies conceived by IVF compared to spontaneous conceptions, although this did not reach statistical significance. Among the patients presenting at the earliest gestational age range, median PAPP-A was significantly lower (0.82 MoM versus 1.68 MoM, P = 0.036) in the IVF pregnancies. b-hCG and NTmeasurements did not differ significantly between the two groups at any gestational age. However, there was a trend towards increased median NT measurements in IVF pregnancies from 11.5 12.5 weeks of gestation (1.55 mm versus 1.45 mm, P = 0.09) compared to the controls at the same gestational age. CONCLUSION: In singleton pregnancies conceived by IVF, PAPP-A levels appear to be lower early in gestation. Larger studies are necessary to explore the possibility of using appropriate adjustment factors to correct for IVF gestations.