Accuracy of self-reported smoking status in first trimester aneuploidy screening.
OBJECTIVE
To review the accuracy of self-reporting of smoking status in our first trimester screening population and to assess the levels of pregnancy-associated plasma protein-A (PAPP-A) and free-β human chorionic gonadotropin (free-hCGβ) in women who were classified for smoking status by serum cotinine concentrations and self-reporting.


METHODS
Cotinine concentration was determined in the stored serum 696 self-reported smokers and 442 self-reported non-smokers. PAPP-A and free-hCGβ multiples of the medians (MoMs) determined at screening were reverted to uncorrected for self-reported smoking status.


RESULTS
A total of 21.7% of those self-reporting as non-smokers had increased serum cotinine concentrations (using a cut-off of 13.7 ng/mL), indicating a positive smoking status. This under-reporting meant that serum PAPP-A and free-hCGβ MoMs were greater reduced in smokers classified by cotinine levels (17.2% and 9.7%) than in those classified by self-reporting (14.6% and 2.8%). Women who were classified as smokers at conception but had stopped at some time afterwards did not have significantly reduced marker MoMs to non-smokers.


CONCLUSIONS
Self-reporting results in under-representation of smoking in our population, resulting in a significant bias and inflated screen-positive rates.
Prenatal Research Unit, Department of Clinical Biochemistry, King George Hospital, Barley Lane, Goodmayes, IG3 8YB, UK. KevinSpencer1@aol.com
Kevin
K
Spencer
Nicholas J
NJ
Cowans
D000293:Adolescent; D000328:Adult; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000097:blood*; D003367:Cotinine / Q000097:blood*; D005189:False Positive Reactions; D005260:Female; D006801:Humans; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000378:metabolism*; D011296:Prenatal Diagnosis; D057566:Self Report / Q000592:standards*; D012907:Smoking / Q000097:blood*; D014314:Trisomy / Q000175:diagnosis*; D055815:Young Adult
D018997:Chorionic Gonadotropin, beta Subunit, Human; D011266:Pregnancy-Associated Plasma Protein-A; C579283:PAPPA protein, human; D003367:Cotinine