In combined first-trimester Down syndrome screening, the false-positive rate is not higher in pregnancies conceived after assisted reproduction compared with spontaneous pregnancies.

The maternal serum levels of pregnancy-associated plasma protein-A (PAPP-A) were reduced in hormonally stimulated pregnancies in the in vitro fertilization and intracytoplasmic sperm injection groups (N=176; PAPP-A: 0.82) and in the entire assisted reproduction group (N=282; PAPP-A: 0.83) as compared with controls (N=24,783; PAPP-A: 0.94). However, the false-positive rate of first-trimester combined screenings was not statistically significantly increased in assisted reproduction pregnancies after adjustment for maternal age.