Effect of in vitro fertilization on human chorionic gonadotropin serum concentrations and Down's syndrome screening.
OBJECTIVE
To investigate the association between IVF and Down's syndrome screening analytes (alpha-fetoprotein [AFP] and hCG) during the second trimester.


METHODS
Retrospective analysis.


METHODS
University-based tertiary care infertility clinic.


METHODS
Data on 41 consecutive singleton IVF pregnancies and 4,935 naturally occurring singleton pregnancies.


RESULTS
Maternal serum hCG concentrations were elevated (mean 1.52 multiples of the median [MoM]) in IVF pregnancies, whereas there were no significant differences in AFP levels (mean 1.02 MoM). The mean maternal age was higher in the subjects than in controls (33.8 compared with 28.7 years). In relation to Down's syndrome risk assessment, the pattern of the two markers, together with maternal age, indicated high risk more often in the study subjects than in the controls. In vitro fertilization patients had a false-positive rate of 26.8% compared with 6.6% in women without fertility problems.


CONCLUSIONS
The increased false-positive rate in Down's syndrome screening is related not only to advanced maternal age but also, in part, to the elevated hCG concentrations observed in pregnancies after assisted reproduction. The mechanism behind increased hCG production remains to be elucidated, but it may be an effect associated with infertility or the procedures by which these women conceive. To provide an objective assessment of an individual patient's risk of fetal abnormality, the impact of IVF on hCG biochemistry should be studied further in larger samples and adjustments made if appropriate.
Heinonen
S
S
Department of Obstetrics and Gynecology, University Hospital of Kuopio, Finland.
Ryynänen
M
M
Kirkinen
P
P
Hippeläinen
M
M
Saarikoski
S
S
D000328:Adult; D006063:Chorionic Gonadotropin / Q000097:blood*; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis*; D005189:False Positive Reactions; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008403:Mass Screening / Q000379:methods*; D016011:Normal Distribution; D011247:Pregnancy / Q000097:blood*; D012189:Retrospective Studies; D000509:alpha-Fetoproteins / Q000032:analysis
D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins