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Repeat maternal serum alpha‐fetoprotein testing in antenatal screening programmes for Down's syndrome
Author(s) -
CUCKLE HOWARD S.,
WALD NICHOLAS J.,
NANCHAHAL KIRAN,
DENSEM JAMES
Publication year - 1989
Publication title -
bjog: an international journal of obstetrics and gynaecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.157
H-Index - 164
eISSN - 1471-0528
pISSN - 1470-0328
DOI - 10.1111/j.1471-0528.1989.tb01576.x
Subject(s) - medicine , down syndrome , obstetrics , pregnancy , alpha fetoprotein , gestation , risk assessment , triple test , gynecology , pediatrics , fetus , biology , genetics , computer security , psychiatry , hepatocellular carcinoma , computer science
Summary. The risk of having a Down's syndrome term pregnancy was estimated using maternal age and the results of two maternal serum alpha‐fetoprotein (AFP) tests carried out between 14 and 20 weeks gestation. The estimates of risk were derived from published data and the AFP results from nine affected and 145 unaffected pregnancies in which repeat testing had been carried out. Repeat AFP testing is unjustified in antenatal screening programmes for Down's syndrome, but if a second test happens to have been done, the appropriate estimate of risk that would be applicable when counselling individual patients depends on both results. For example a woman aged 35 years and 6 months with a first AFP level of 0–50 multiples of the normal median (MoM) was estimated to have a risk of 1:172. If a second test were done on a fresh sample and the AFP level were 0·80 MoM then the estimated risk would be 1:216 which is higher than the estimated risk of 1:353 obtained if the second test were regarded as the only result. Estimates of risk are given for maternal serum AFP results in first and second tests ranging from 0·40 to 2·50 MoM.