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

Routine 36-week scan: diagnosis of fetal abnormalities

OBJECTIVES

To investigate further the incidence and types of fetal abnormality identified at a routine 36-week ultrasound examination, which had not been diagnosed in previous scans at 20 weeks and 12 weeks' gestation, and to report the fetal abnormalities that are diagnosed only postnatally.

METHODS

This was a prospective study of 104 151 women with a singleton pregnancy attending for a routine ultrasound examination at 35 + 0 to 36 + 6 weeks' gestation. In each case, a detailed examination was carried out for the diagnosis of fetal abnormality. All women had undergone a previous ultrasound examination at 19 + 0 to 23 + 6 weeks and 95 801 (92.0%) women also had a scan at 11 + 0 to 14 + 1 weeks. We excluded pregnancies with known aneuploidy. Fetal abnormalities were classified according to the affected major organ system, and the type and incidence of new abnormalities were determined.

RESULTS

There were four main findings of this study. First, in the study population, abnormality was identified in 2552 (2.5%) fetuses/neonates. Second, at the 36-week scan, abnormality was detected in 2144 (2.1%) fetuses and the most common abnormalities first detected at the 36-week scan were ventricular septal defect, unilateral or bilateral hydronephrosis, unilateral empty renal fossa (with or without pelvic kidney), unilateral or bilateral duplex kidney and mild ventriculomegaly. Third, 1341 (62.5%) of the fetuses with abnormality detected at the 36-week scan had been diagnosed previously during the first or second trimester and therefore, the incidence of abnormality detected for the first time in the third trimester was 0.77% (803/104 151). The most common abnormalities that were diagnosed exclusively for the first time during the third-trimester scan were ovarian cyst, achondroplasia, microcephaly, vein of Galen malformation and hematocolpos. Fourth, the incidence of abnormality detected for the first time postnatally was 0.39% (408/104 151). The most common abnormalities detected for the first time postnatally were polydactyly, oligodactyly or syndactyly, hypospadias/epispadias, mild talipes treated with physiotherapy, ventricular septal defect and isolated cleft palate. The most common abnormalities diagnosed exclusively for the first time postnatally were isolated cleft palate, anal atresia, atrial septal defect and esophageal atresia with fistula.

CONCLUSION

A high proportion of fetal abnormalities are detected for the first time during a routine 36-week scan. Such diagnosis and subsequent management, including the selection of timing and place for delivery and postnatal investigation, could potentially improve postnatal outcome. © 2025 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

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.

Routine 36-week scan: diagnosis and outcome of abnormal fetal presentation

OBJECTIVES

First, to report the incidence of non-cephalic presentation at a routine 36-week ultrasound scan, the uptake and success of external cephalic version (ECV) and the incidence of spontaneous rotation from non-cephalic to cephalic presentation. Second, to determine the maternal and pregnancy characteristics that provide a significant contribution to the prediction of non-cephalic presentation at the 36-week scan, successful ECV from non-cephalic to cephalic presentation and spontaneous rotation from non-cephalic to cephalic presentation.

METHODS

This was a retrospective analysis of prospectively collected data from 107 875 women with a singleton pregnancy who had undergone a routine ultrasound scan at 35 + 0 to 36 + 6 weeks' gestation. Patients with breech or transverse/oblique presentation were divided into two groups: those scheduled for elective Cesarean section for a fetal or maternal indication other than abnormal presentation, and those that would potentially require ECV. The latter group was reassessed after 1-2 weeks and, if the abnormal presentation persisted, the parents were offered ECV or elective Cesarean section at 38-40 weeks' gestation. Multivariable logistic regression analysis was carried out to determine which maternal and pregnancy characteristics provided a significant contribution in the prediction of non-cephalic presentation at the 36-week scan, successful ECV from non-cephalic to cephalic presentation and spontaneous rotation from non-cephalic to cephalic presentation.

RESULTS

At the 36-week scan, fetal presentation was cephalic in 101 664 (94.2%) pregnancies and either breech, transverse or oblique in 6211 (5.8%). In 0.3% of cases with cephalic presentation at the 36-week scan, there was subsequent spontaneous rotation to non-cephalic presentation, and in half of these, the diagnosis was made during labor or at birth. ECV was attempted in 1584/6211 (25.5%) pregnancies with non-cephalic presentation at the 36-week scan and was successful in only 44.1% of cases. In the remaining 74.5% of cases, ECV was not attempted because of any of the following reasons: ECV was declined; Cesarean section was planned for a reason other than abnormal presentation; ECV was planned for the subsequent 1-2 weeks but, in the meantime, there was spontaneous rotation to cephalic presentation; or there was spontaneous onset of labor or rupture of membranes before planned ECV. In 5513/6211 (88.8%) pregnancies with non-cephalic presentation at the 36-week scan, ECV was not attempted or was unsuccessful, and in 37.7% of these, there was subsequent spontaneous rotation to cephalic presentation. Among the 6211 pregnancies with non-cephalic presentation at the 36-week scan, the presentation at birth was cephalic in 43.8%; in 74.8%, this was due to spontaneous rotation, and in 25.2%, it was due to successful ECV. Multivariable analysis demonstrated that the likelihood of non-cephalic presentation at the 36-week scan, that of successful ECV and that of spontaneous rotation from non-cephalic to cephalic presentation was affected by several maternal and pregnancy characteristics, but the predictive performance for these events was poor, with the area under the receiver-operating-characteristics curve ranging from 0.608 to 0.717 and the detection rate at a 10% false-positive rate ranging from 19.0% to 33.7%.

CONCLUSIONS

Routine ultrasound examination at 35 + 0 to 36 + 6 weeks' gestation could improve pregnancy outcome by substantially reducing the risk of unexpected abnormal presentation in labor. However, an additional ultrasound scan for fetal presentation should be considered in all women when they present in labor. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Routine 36-week scan: prediction of small-for-gestational-age neonate

OBJECTIVES

First, to compare the predictive performance of routine ultrasonographic estimated fetal weight (EFW) at 31 + 0 to 33 + 6 and 35 + 0 to 36 + 6 weeks' gestation for delivery of a small-for-gestational-age (SGA) neonate. Second, to compare the predictive performance of EFW at 36 weeks' gestation for SGA vs fetal growth restriction (FGR) at birth. Third, to compare the predictive performance for delivery of a SGA neonate of EFW < 10th percentile vs a model combining maternal demographic characteristics and elements of medical history with EFW.

METHODS

This was a retrospective analysis of prospectively collected data in 21 676 women with a singleton pregnancy who had undergone routine ultrasound examination at 31 + 0 to 33 + 6 weeks' gestation and 107 875 women with a singleton pregnancy who had undergone routine ultrasound examination at 35 + 0 to 36 + 6 weeks. Measurements of fetal head circumference, abdominal circumference and femur length were used to calculate EFW according to the Hadlock formula and this was expressed as a percentile according to the Fetal Medicine Foundation fetal and neonatal population weight charts. The same charts were used to diagnose SGA neonates with birth weight < 10th or < 3rd percentile. FGR was defined as birth weight < 10th percentile in addition to Doppler anomalies. For each gestational-age window at screening, the screen-positive rate and detection rate were calculated at different EFW cut-offs between the 10th and 50th percentiles for predicting the delivery of a SGA neonate with birth weight < 10th or < 3rd percentile, either within 2 weeks or at any time after assessment. The areas under the receiver-operating-characteristics curves (AUC) of screening for a SGA neonate by EFW at 31 + 0 to 33 + 6 weeks and at 35 + 0 to 36 + 6 weeks were compared.

RESULTS

The predictive performance of routine ultrasonographic examination during the third trimester for delivery of a SGA neonate is higher if: first, the scan is carried out at 35 + 0 to 36 + 6 weeks' gestation rather than at 31 + 0 to 33 + 6 weeks; second, the outcome measure is birth weight < 3rd rather than < 10th percentile; third, the outcome measure is FGR rather than SGA; fourth, if delivery occurs within 2 weeks after assessment rather than at any time after assessment; and fifth, prediction is performed using a model that combines maternal demographic characteristics and elements of medical history with EFW rather than EFW < 10th percentile alone. At 35 + 0 to 36 + 6 weeks' gestation, detection of ≥ 85% of SGA neonates with birth weight < 10th percentile born at any time after assessment necessitates the use of EFW < 40th percentile. Screening at this percentile cut-off predicted 95% and 98% of neonates with birth weight < 10th and < 3rd percentile, respectively, born within 2 weeks after assessment, and the respective values for neonates born at any time after assessment were 85% and 93%.

CONCLUSION

Routine third-trimester ultrasonographic screening for a SGA neonate performs best when the scan is carried out at 35 + 0 to 36 + 6 weeks' gestation, rather than at 31 + 0 to 33 + 6 weeks, and when EFW is combined with maternal risk factors to estimate the patient-specific risk. © 2024 The Author(s). Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

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.