Maternal serum unconjugated oestriol and human chorionic gonadotrophin levels in pregnancies with insulin-dependent diabetes: implications for screening for Down's syndrome.
OBJECTIVE
To investigate maternal serum unconjugated oestriol (uE3) and human chorionic gonadotrophin (hCG) levels in pregnant women with insulin-dependent diabetes mellitus and to consider the implications of the results for antenatal screening for Down's syndrome.


METHODS
Descriptive study using stored antenatal serum samples.


METHODS
Stored serum samples collected from women receiving routine antenatal care in Oxford.


METHODS
126 singleton pregnancies in 92 women with insulin-dependent diabetes mellitus and for each pregnancy, two pregnancies without diabetes matched for gestational age and duration of storage of the serum sample. None of the pregnancies was associated with fetal neural tube defect or Down's syndrome.


METHODS
Maternal serum uE3 and hCG levels at 15-22 weeks gestation. Alpha-fetoprotein (AFP) levels were also measured for comparison.


RESULTS
The median uE3 level in the diabetic pregnancies was 0.92 multiples of the median (MoM) for pregnancies without diabetes at the same gestational age (P less than 0.05); and the hCG level was 0.95 MoM (P = 0.48). The median AFP level was also reduced to 0.77 MoM (P less than 0.001).


CONCLUSIONS
The reduction in uE3 and AFP levels in insulin-dependent diabetic pregnancies is sufficiently great to be taken into account in maternal serum screening programmes for Down's syndrome. Dividing the uE3 and AFP levels in such pregnancies by the corresponding median for insulin-dependent diabetic pregnancies will yield a similar false-positive rate in pregnancies with and without insulin-dependent diabetes mellitus.
Department of Environmental and Preventive Medicine, St Bartholomew's Hospital Medical College, London.
N J
NJ
Wald
H S
HS
Cuckle
J W
JW
Densem
R B
RB
Stone
D006063:Chorionic Gonadotropin / Q000097:blood*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood*; D004314:Down Syndrome / Q000097:blood / Q000175:diagnosis*; D004964:Estriol / Q000097:blood*; D005260:Female; D005315:Fetal Diseases / Q000175:diagnosis*; D006801:Humans; D011247:Pregnancy; D011254:Pregnancy in Diabetics / Q000097:blood*; D011296:Prenatal Diagnosis; D000509:alpha-Fetoproteins / Q000032:analysis
D006063:Chorionic Gonadotropin; D000509:alpha-Fetoproteins; D004964:Estriol