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Serum markers for Down's syndrome in women who have had in vitro fertilisation: implications for antenatal screening
Author(s) -
Wald N. J.,
White N.,
Morris J. K.,
Huttly W. J.,
Canick J. A.
Publication year - 1999
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.1471-0528.1999.tb08186.x
Subject(s) - in vitro fertilisation , medicine , gynecology , obstetrics , pregnancy , down syndrome , gestation , biology , genetics , psychiatry
To examine the Down's syndrome screening positive rate among in vitro fertilisation (IVF) pregnancies, we measured second trimester serum marker levels in singleton IVF pregnancies (cases) and in five non–IVF pregnancies (controls) matched to each case for gestational age, age of mother, and duration of storage of the serum sample. There were 151 IVF pregnancies in which alpha fetoprotein, unconjugated oestriol (uE 3 ), free β–human chorionic gonadotrophin (hCG) and total hCG were measured, 104 IVF pregnancies in which free α‐hCG was measured, and 39 IVF pregnancies in which inhibin A was measured. Median uE 3 levels were 6% lower ( P = 0.003 ), median free β–hCG 9% higher ( P = 0.024 ), and median total hCG 14% higher ( P = 0.026 ) in IVF pregnancies compared with controls. The screen positive rate in the IVF pregnancies (28%) was about twice as high as that in controls (17%). High hCG levels may be explained by progesterone remaining high in IVF pregnancies. The low uE 3 levels remain unexplained. In Down's syndrome screening in IVF pregnancies hCG and uE 3 values should be adjusted to avoid the high screen positive rate.