Background The current Down’s screening programme has the potential to identify pregnancies at risk of other significant chromosomal problems. However unless at increased risk for trisomy 21 these pregnancies are usually reported as low risk. This leaves women and their healthcare professionals unaware of potential problems and denies them opportunities for earlier intervention if desired.

Methods All data from our regional CT screening programme where both the PAPP-A and hCG result fell below the 0.3 MoM were identified and pregnancy outcome reviewed.

Results A total of 112 cases were identified comprising approx 0.16% of women screened.

The karyotype abnormalities were 30-trisomy18, 13-triploidy and 6 others. There were no cases of trisomy 21.

Discussion Clinical teams and screening midwives need to be aware of the implications of a low/low result on screening. Ultrasound does not help to identify pregnancies where diagnostic testing may be of value. This group of women should not be labelled as low risk and should have the opportunity for an informed discussion about the implications of their results with a fetal medicine centre and consideration given to diagnostic testing. If the pregnancy continues they should be managed as high risk with obstetric input to monitoring of fetal growth and BP.