MATERNAL SERUM INHIBIN-A IN PREGNANCIES WITH INSULIN-DEPENDENT DIABETES-MELLITUS - IMPLICATIONS FOR SCREENING FOR DOWNS-SYNDROME

A nested case-control study using stored serum samples collected as pa rt of a prospective study of the outcome of pregnancy was performed to investigate concentrations of (dimeric) inhibin-A in maternal serum b etween 15 and 22 weeks of pregnancy in 126 pregnancies among 92 women with insulin-dependent diabetes mellitus (IDDM). Each IDDM pregnancy w as matched with two control singleton pregnancies for gestational age (same completed week) and duration of sample storage (same calendar qu arter). The median inhibin-il level in the IDDM pregnancies was 0.88 m ultiples of the median (MOM) for pregnancies without IDDM at the same gestational age (P=0.05) (95 per cent confidence interval 0.78-1.00) o r 0.91 MOM after adjustment for maternal weight. These results enable inhibin-A values to be adjusted so that prenatal screening for Down's syndrome can be performed using this marker in IDDM pregnancies as wel l as in non-diabetic pregnancies.