Evidence that systemic vascular resistance is increased before the development of gestational diabetes mellitus

The ophthalmic artery, which is the first branch of the internal carotid artery, has a Doppler velocity waveform with 2 systolic peaks. The ratio of the peak systolic velocity of the second wave divided by that of the first wave is used to reflect increased peripheral resistance. Previous studies in the first, second, and third trimesters of pregnancy have reported that in pregnant women who subsequently develop preeclampsia, the peak systolic velocity ratio is increased. Both preeclampsia and gestational diabetes mellitus are associated with endothelial dysfunction and an increased risk for cardiovascular diseases during the first decade after pregnancy.

This study aimed to compare the ophthalmic artery peak systolic velocity ratio at 11 to 13 weeks' gestation of women who subsequently develop gestational diabetes mellitus with that of unaffected pregnant women and those who develop preeclampsia.

This was a prospective observational study of women who attended the King's College Hospital, London, United Kingdom, for a routine hospital visit at 11⁺⁰ to 13⁺⁶ weeks' gestation. This visit included recording of the maternal demographic characteristics and medical history, an ultrasound examination for fetal anatomy and growth, assessment of the flow velocity waveforms from the maternal ophthalmic arteries, calculation of the peak systolic velocity ratio, and measurement of the mean arterial pressure. Linear regression was performed to predict the ophthalmic artery peak systolic velocity ratio based on maternal characteristics and the mean arterial pressure. The peak systolic velocity ratio in the group with gestational diabetes mellitus was compared with that of preeclamptic and unaffected pregnancies.

A total of 3999 women were included in this study, including 375 (9.8%) who developed gestational diabetes mellitus and 101 (2.5%) who developed preeclampsia. In the gestational diabetes mellitus group, 161 (43.3%) were treated by diet alone, 130 (34.1%) were treated with metformin, and 84 (22.6%) received insulin with or without metformin. Prediction of peak systolic velocity ratio was provided by development of preeclampsia, maternal age, body mass index, mean arterial pressure, first-degree family history of diabetes mellitus, family history of preeclampsia, Asian ethnicity, and smoking. There was no significant contribution from gestational diabetes mellitus. Among women who developed gestational diabetes mellitus that required insulin treatment, the ophthalmic artery peak systolic velocity ratio (0.67±0.09) was higher (P<.001) than that in unaffected pregnancies (0.63±0.10), but it was not significantly different from that in the preeclampsia group (0.69±0.10; P=.90).

Among women who developed severe gestational diabetes mellitus that required insulin treatment, there was evidence of increased peripheral resistance, which was apparent from the first trimester of pregnancy.