Ophthalmic artery Doppler at 36 weeks' gestation in prediction of pre-eclampsia: validation and update of previous model

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

BACKGROUND

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.

OBJECTIVE

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.

STUDY DESIGN

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.

RESULTS

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).

CONCLUSION

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.

Ophthalmic artery Doppler and biomarkers of impaired placentation at 36 weeks' gestation in pregnancies with small fetuses

OBJECTIVES

First, to compare ophthalmic artery peak systolic velocity (PSV) ratio and biomarkers of impaired placentation at 36 weeks' gestation in women who delivered a small-for-gestational-age (SGA) or growth-restricted (FGR) neonate, in the absence of hypertensive disorder, with those of women who developed pre-eclampsia (PE) or gestational hypertension (GH) and of women unaffected by SGA, FGR, PE or GH. Second, to examine the associations of PSV ratio, uterine artery pulsatility index (UtA-PI), placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) with birth-weight Z-score or percentile.

METHODS

This was a prospective observational study of women with a singleton pregnancy attending for a routine hospital visit at 35 + 0 to 36 + 6 weeks' gestation. This visit included recording of maternal demographic characteristics and medical history, ultrasound examination of fetal anatomy and growth, and measurement of maternal ophthalmic artery PSV ratio, UtA-PI, PlGF and sFlt-1. Values of PSV ratio, UtA-PI, PlGF and sFlt-1 were converted to multiples of the median (MoM) or delta values. Median MoM or deltas of these biomarkers in the SGA, FGR, PE and GH groups were compared with those in the unaffected group. Regression analysis was used to examine the relationship of PSV ratio delta, UtA-PI MoM, PlGF MoM and sFlt-1 MoM with birth-weight Z-score, after exclusion of PE and GH cases.

RESULTS

The study population of 9033 pregnancies included 7696 (85.2%) that were not affected by FGR, SGA, PE or GH, 182 (2.0%) complicated by FGR in the absence of PE or GH, 698 (7.7%) with SGA in the absence of FGR, PE or GH, 236 (2.6%) with PE and 221 (2.4%) with GH. Compared with unaffected pregnancies, in the FGR and SGA groups, the PSV ratio delta and sFlt-1 MoM were increased and PlGF MoM was decreased; UtA-PI MoM was increased in the FGR group but not the SGA group. The magnitude of the changes in biomarker values relative to the unaffected group was smaller in the FGR and SGA groups than that in the PE and GH groups. In non-hypertensive pregnancies, there were significant inverse associations of PSV ratio delta and UtA-PI MoM with birth-weight Z-score, such that the values were increased in small babies and decreased in large babies. There was a quadratic relationship between PlGF MoM and birth-weight Z-score, with low PlGF levels in small babies and high PlGF levels in large babies. There was no significant association between sFlt-1 MoM and birth-weight Z-score.

CONCLUSIONS

Ophthalmic artery PSV ratio, reflective of peripheral vascular resistance, and UtA-PI, PlGF and sFlt-1, biomarkers of impaired placentation, are altered in pregnancies complicated by hypertensive disorder and, to a lesser extent, in non-hypertensive pregnancies delivering a SGA or FGR neonate. The associations between the biomarkers and birth-weight Z-score suggest the presence of a continuous physiological relationship between fetal size and peripheral vascular resistance and placentation, rather than a dichotomous relationship of high peripheral resistance and impaired placentation in small compared to non-small fetuses. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.