Additive effect of factors related to assisted conception on the reduction of maternal serum PAPP A concentrations and the increased false positive rates in first trimester Down syndrome screening

Capsule:
Among assisted conceptions, only nondonor in vitro fertilization/intracytoplasmic sperm injection singleton pregnancies need adjustments of the PAPP-A in first-trimester Down syndrome screening.

Authors:
José Bellver, M.D., Cristina Casanova, M.D., Nicolás Garrido, Ph.D., Coral Lara, M.D., José Remohí, M.D., Antonio Pellicer, M.D., Vicente Serra, M.D.

Volume 100, Issue 5, Pages 1314-1320.e3, November 2013

Abstract:

Objective:
To analyze whether assisted conceptions need adjustments in first-trimester Down syndrome screening and why modifications in screening markers occur.

Design:
Eleven-year cohort retrospective analysis.

Setting:
Maternal-fetal medicine unit.

Patient(s):
Two thousand eleven naturally conceived normal singleton pregnancies and 2,042 normal singleton pregnancies achieved with assisted conception: 350 by IUI and 1,692 with IVF (n = 328) or intracytoplasmic sperm injection (ICSI; n = 1,364), using nondonor (n = 1,086) or donated ova (n = 606), with fresh (n = 1,432) or frozen (n = 260) embryos.

Intervention(s):
Comparison of ultrasound and biochemical markers of first-trimester Down syndrome screening according to the mode of conception and considering the clinical and laboratory parameters related.

Main Outcome Measure(s):
Nuchal translucency (NT), PAPP-A and free βhCG maternal serum concentrations, and false-positive rates (FPRs).

Result(s):
NT is unaffected by the mode of conception. Singleton pregnancies achieved by IVF and ICSI with nondonor oocytes have reduced maternal serum PAPP-A and increased FPR, which are significant only in ICSI cycles. Pregnancies from frozen embryos with hormone therapy also show decreased PAPP-A but without affecting the FPR. Elevated maternal serum fβhCG levels in oocyte donation do not influence the FPR.

Conclusion(s):
Among assisted conceptions, only nondonor IVF/ICSI singleton pregnancies need adjustments of the maternal serum PAPP-A in first-trimester Down syndrome screening.

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