The association between gestational diabetes mellitus and first trimester aneuploidy screening markers

To establish whether maternal serum first trimester concentrations of PAPP-A and free hCGβ are altered in pregnancies that subsequently are diagnosed by an oral glucose tolerance test (OGTT) with gestational diabetes mellitus (GDM).

Over the period 2009 and 2011, the results for women who had first trimester screening for aneuploidy were matched with those having an oral glucose tolerance test at 22-26 weeks for suspected GDM. Free hCGβ, PAPP-A and NT MoMs were compared amongst the group having an OGTT with confirmed GDM and those in which GDM was not confirmed. A second comparison group consisted of all non-aneuploidy singleton pregnancies in which no OGTT was performed.

During the three-year period, 27,660 singleton pregnancies were screened of which 7429 cases had an OGTT of which 870 cases were classed as GDM by WHO criteria. There was a significant 7-9% reduction in both PAPP-A and free hCGβ MoM in the GDM group compared with either the OGTT non-GDM group or the remaining pregnancies with no known risk factors for evidence of GDM. There was no difference in the NT measurements.

First trimester concentrations of PAPP-A and free hCGβ are reduced in pregnancies that subsequently are diagnosed with GDM and may be useful in further screening algorithms for this disorder although the sensitivity alone is quite poor.