Low maternal serum levels of pregnancy associated plasma protein A (PAPP-A) in the first trimester in association with abnormal fetal karyotype.
OBJECTIVE
To assess the relation between maternal serum pregnancy associated plasma protein A (PAPP-A) in the first trimester and the outcome of pregnancy by karyotype.


METHODS
A retrospective study of PAPP-A levels in blood samples collected prior to chorionic villus sampling.


METHODS
Milan, Italy.


METHODS
Five hundred twenty-two women aged 20 to 47, at 7 to 11 weeks gestation, prior to undergoing chorionic villus sampling. Four hundred forty-five women had a pregnancy with a normal karyotype; in 30 pregnancies the karyotype was abnormal (including 14 cases of Down's syndrome and 7 of trisomy 18).


METHODS
Normal or abnormal fetal karyotype. Serum PAPP-A at 6 to 11 weeks gestation measured by radioimmunoassay.


RESULTS
The median value of PAPP-A in the abnormal group was 0.27 multiples of the normal median (MoM). This is significantly lower than the median value in the normal group (1.01 MoM) (95% CI for the difference 0.46-0.84 MoM; P < 0.00001 Mann-Whitney test).


CONCLUSIONS
There is an association between low levels of PAPP-A in the first trimester with chromosome anomalies. Screening by measurement of PAPP-A might detect 60% of cases of Down's syndrome in the first trimester with a false positive rate of 5%.
Brambati
B
B
Academic Unit of Obstetrics & Gynaecology, London Hospital, Whitechapel, UK.
Macintosh
M C
MC
Teisner
B
B
Maguiness
S
S
Shrimanker
K
K
Lanzani
A
A
Bonacchi
I
I
Tului
L
L
Chard
T
T
Grudzinskas
J G
JG
D000328:Adult; D015193:Chorionic Villi Sampling; D002869:Chromosome Aberrations / Q000097:blood* / Q000175:diagnosis; D025063:Chromosome Disorders; D002887:Chromosomes, Human, Pair 18; D004314:Down Syndrome; D005260:Female; D005820:Genetic Testing; D006801:Humans; D007621:Karyotyping; D008875:Middle Aged; D011247:Pregnancy; D011256:Pregnancy Outcome; D011261:Pregnancy Trimester, First; D011266:Pregnancy-Associated Plasma Protein-A / Q000032:analysis*; D011296:Prenatal Diagnosis / Q000379:methods; D012189:Retrospective Studies; D014314:Trisomy
D011266:Pregnancy-Associated Plasma Protein-A