Adjustment of maternal serum alpha-fetoprotein levels in women with pregestational diabetes.

Objective: Decreased second trimester levels of maternal serum alpha-fetoprotein (MSAFP) have been reported in women with pregestational diabetes leading some laboratories to use a correction factor. The aim of this study is to determine if MSAFP levels in pregnant women with diabetes managed on oral antidiabetic agents is lower than non-diabetic controls and require adjustment similar to those on insulin.
Study Design: We performed a nested case/control study of an existing dataset using women with pregestational diabetes who had routine MSAFP values available.
Results: Before adjusting the MSAFP value for weight, both the diabetic patients who used insulin (n = 68) and those who used oral antidiabetic agents (n = 37) showed a non-significant trend toward a lower multiples of the median (MoM) as compared with controls (n = 244). After converting the raw MSAFP values to race-adjusted MoM and adjusting for weight, the median MSAFP MoM for women taking insulin (1.01) versus those on oral antidiabetic agents (1.00) were essentially the same. Furthermore, both of the diabetic groups were virtually identical to non-diabetic controls.
Conclusions: In our study, women with pregestational diabetes managed on either insulin or oral antidiabetic agents had weight-adjusted MSAFP MoM levels equivalent to those in control pregnancies and did not require a correction factor.
(Copyright © 2011 John Wiley & Sons, Ltd.)