Background: Maternal hyperglycaemia alone does'nt explain the incidence of large for gestational age offspring (LGA) amongst women with T1DM. Placental vascular development is regulated by angiogenic factors. Placental growth factor (PIGF) is such a factor with a PlGF >100 signifying a well-developed placenta. Co-measurement of PlGF and SFLT-1 (soluble receptor antagonist to VEGF), combined as a ratio, is predictive of maternal vascular perfusion. A low sFLT-1:PlGF (<85) is a marker of good placental health. We assessed if markers of placental function and glycemic control can explain variations in birthweight in women with T1DM.

Methods: Amongst 157 women who participated in CONCEPTT; PlGF, sFLT-1:PlGF and a HbA1c< or >6.5% at randomisation and 34 weeks' gestation were assessed. Two separate linear regression models were used to test for a differential effect of placental function on mean birth weight in those with different levels of glycemic control, one using sFLT-1:PlGF and the other PlGF.

Results: No significant relationship was found between birthweight and markers of placental function and glycemic control at randomisation. At 34 weeks, the relationship of birth weight to sFLT-1: PlGF differed depending upon HbA1c (p=0.007). Where HbA1c< 6.5%, birth weights were similar for a sFLT-1:PlGF <85 (3592g) and >85 (3699g). Where HbA1c > 6.5%, birthweights were higher with a sFLT-1:PlGF < 85 (3809g) vs. > 85 (3355g). A similar pattern emerged for PlGF alone, with a differential effect of a healthy placenta on birthweight dependent upon glycemic control (p=0.013). Where HbA1c<6.5%, birthweights were similar (3635±556g and 3604±602g) with low and high PlGF. Where HbA1c>6.5%, an elevated PlGF (>100) resulted in higher birth weight than in those with lower PlGF (3822g ±679 vs. 3344g ±556).

Conclusion: In women with T1DM, the combination of a healthy placenta with poor glycemic control resulted in the highest birthweights. Tighter glycemic control to avoid LGA is needed in women with healthy placental function.


S. Bacon: None. D. Burger: None. M. Tailor: None. G.A. Tomlinson: None. H.R. Murphy: Advisory Panel; Self; Medtronic MiniMed, Inc. D. Feig: Advisory Panel; Self; Medtronic. Speaker's Bureau; Self; Medtronic.

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