Retinal small vessel narrowing in women with gestational diabetes, pregnancy-associated hypertension, or small-for-gestational age babies

Background: Gestational diabetes, pregnancy-associated hypertension and small-for-gestational age babies are all associated with impaired placental vascularisation. This study compared the effects of these conditions the systemic small vessel calibre that was examined in the retina.Methods: This was a cross-sectional observational study of consecutive pregnant women recruited from an antenatal clinic. Participants underwent a Glucose Tolerance Test, BP measurements, and were examined for small-for-gestational age babies as per national guidelines. They also underwent retinal photography with a non-mydriatic camera, and vessel calibres were measured with a validated semi-quantitative system at a retinal grading centre. Some participants also underwent testing of retinal vascular responsiveness to a flickering light.Results: Women with gestational diabetes (n = 68) had a higher mean arterial pressure (85 +/- 9 mm Hg) than normal pregnant women (n = 27, 80 +/- 8 mmHg, p = 0.01). They also had smaller mean retinal arteriole (147.5 +/- 13.6 mu m and 159.7 +/- 6.7 mu m respectively, p < 0.01) and venular calibre (221.0 +/- 13.4 mu m and 232.8 +/- 20.1 mu m respectively, p < 0.01) than normal. However their babies' mean birth weights were not different from normal (3,311 +/- 558 g and 3,401 +/- 600 g respectively, p = 0.48). They also demonstrated a trend to reduced retinal arteriolar dilatation (3.5 +/- 1.3%, n = 23) in response to vasodilatory stimuli (4.4 +/- 1.8%) (n = 11) (p = 0.08) consistent with endothelial dysfunction. Women with pregnancy-associated hypertension (n = 35) had a higher mean arterial pressure (101 +/- 12 mm Hg, p < 0.01), a smaller mean retinal arteriolar calibre (139.9 +/- 10.6 mu m, p < 0.0001), and a lower baby mean birth weight than for normal pregnancies (3,095 +/- 443 g, p = 0.02). Likewise, women with small-for-gestational age babies (n = 31) had a higher mean arterial pressure (89 +/- 19 mm Hg, p = 0.03), a smaller mean retinal arteriolar calibre (141.6 +/- 12.8 mu m, p < 0.01) and a lower baby mean birth weight than for normal pregnancies (2,468 +/- 324 g, p < 0.0001).Conclusion: Mean retinal arterial calibre was reduced in women with gestational diabetes, pregnancy-associated hypertension or small-for-gestational age babies. The reduction in calibre was greatest in pregnancy-associated hypertension and small-for-gestational age babies. Systemic arteriole narrowing may contribute to the pathogenesis of placental vascular dysfunction in these conditions.

Automated summary

The study compared the effects of gestational diabetes, pregnancy-associated hypertension, and small-for-gestational age babies on systemic small vessel calibre examined in the retina. Results showed that women with gestational diabetes, pregnancy-associated hypertension, or small-for-gestational age babies had reduced mean retinal arterial calibre, with the greatest reduction seen in pregnancy-associated hypertension and small-for-gestational age babies.