Uterine artery Doppler: Changing Concepts in Prediction and Prevention of PE and FGR

Sensitivity of uterine artery Doppler pulsatility index in screening for adverse pregnancy outcome in first and second trimesters

PURPOSE

In a poor resource country where screening for adverse pregnancy outcomes using maternal biomarkers seems unattainable, there is a need to search for credible alternatives. This study is, therefore, aimed at determining the sensitivity of uterine artery Doppler pulsatility index (UtAD-PI) in predicting pregnancy outcomes in the first and second trimesters and to establish any statistical difference in mean UtAD-PI in first and second trimesters screening of women with normal and abnormal pregnancy outcomes respectively.

METHODS

This clinical-based, longitudinal, and unpaired cohort study involved 500 pregnant women, who were screened for adverse outcomes using UtAD-PI and delivered in the hospital. These were divided into two groups, each having a training set and a test set. The training set was used to generate the receiver operator characteristic curve and cut-off point while the test set was used to test for sensitivity and specificity of the Ut-ADI in each trimester.

RESULTS

The sensitivity and specificity of UtAD-PI in first-trimester screening are 97% and 76.5% while second-trimester gave sensitivity and specificity of 57.5% and 63.3% respectively. The uterine artery Doppler pulsatility index shows statistically significant differences between normal pregnancy and pregnancy with adverse outcomes (p-value = 0.000).

CONCLUSION

The uterine artery Doppler pulsatility index is a good screening tool for adverse pregnancy outcomes. First-trimester screening of patients for adverse outcomes is more sensitive than the second-trimester screening using UtAD-PI. There is also a statistically significant difference between mean UtAD-PI between normal pregnancy and pregnancy with adverse pregnancy outcomes.

Utilization of Uterine and Umbilical Artery Doppler in the Second and Third Trimesters to Predict Adverse Pregnancy Outcomes: A Nigerian Experience

Objective: To assess the utility of uterine and umbilical artery Doppler in the second and third-trimester in predicting adverse pregnancy outcomes.

Methodology: In a prospective longitudinal study, the demographic, clinical, Doppler ultrasound parameters of the uterine and umbilical arteries of 84 consecutive women attending the antenatal clinic at 22–24 weeks and 116 women at 30–34 weeks gestation and pregnancy outcomes were documented and analyzed.

Results: Pregnant women with adverse pregnancy outcomes had significantly higher second-trimester mean uterine systolic/diastolic (S/D) ratio (p = 0.001), pulsatility index (PI; p = 0.003), umbilical artery S/D (p = 0.016), and resistivity index (RI; p = 0.041) as well as higher third-trimester uterine S/D and PI. While pregnancies with adverse fetal outcomes showed significantly higher uterine artery S/D and PI at the second trimester, third-trimester uterine showed higher S/D, RI, and PI and umbilical artery PI than in women with normal fetal outcomes. The combination of uterine PI and early diastolic notch were predictors of maternal outcomes and correctly predicted 73% (p < 0.001) in the second trimester. By the third trimester, the uterine PI alone was the best predictor and accurately predicted about 62% of maternal outcomes (p = 0.028). In addition, the second-trimester uterine S/D and early diastolic notch and uterine PI in the third trimester correctly predicted 79% and 78% of fetal outcomes, respectively.

Conclusion: Among unselected pregnant women population, the second-trimester Doppler parameters are better predictors of maternal adverse pregnancy outcomes, while adverse fetal outcome prediction by uterine and umbilical Doppler at the second- and the third-trimester parameters are comparable.

The need for implementation of first trimester screening for preeclampsia and fetal growth restriction in low resource settings

Background: Preeclampsia [PE] and fetal growth restriction [FGR] is a major cause of perinatal morbidity in both developed and developing countries but the disease leaves a severe impact in developing countries, due to the late presentation of cases where prevention and treatment becomes impossible. Routine antenatal ultrasound and health checkups in periphery are usually done in first trimester for dating and viability scan, in midtrimester for anomaly scan and in third trimester for safe confinement. Underlying disorder of deep placentation which is unidentified can lead to increased maternal morbidity and fetal compromise between 26 to 34 weeks of gestation The complications present at an irreversible stage where there is no sufficient time even for referral to tertiary care center. Frequent antenatal visits as suggested by WHO would definitely bring down maternal mortality but this increased surveillance when offered to all might be a huge burden to health care providers in low resource settings. An acceptable screening test should help in triaging the high risk group in first trimester itself targeting about only one third of the population for prophylactic therapy and increased antenatal surveillance.The objective of this study is to evaluate the performance and feasibility of different screening protocols in low resource settings.Methodology: Screening for PE and FGR was done at the 11-14 weeks aneuploidy scan as per FMF guidelines. Group I included 6289 women whose risk prediction was done with maternal characteristics [MC], mean arterial pressure [MAP] and Uterine artery Doppler [UAD]. Group II included 2067 women whose risk was predicted with MC, MAP, UAD and PAPP-A. Group III included 576 women whose risk prediction included all parameters with PLGF.Results: Two thousand five hundred fifty-seven cases were screen positive in group I and 602 were screen positive in group II. In group III which included PLGF, 24 were positive for early onset PE and 36 for late onset PE. The number needed to treat [NNT] was 35.9, 29.1 and 10% in Group I, II and III respectively. The detection rate [DR] for PE and FGR was 60% in Group I and DR for FGR in Group II was 85%. In Group III, for early onset PE the DR was 98% and 68% for late onset PE.Conclusion: Screening for PE with available resources in the periphery needs to be implemented to avoid its grave complications. Traditional screening for PE by NICE guidelines can be adopted but may have a detection rate of only 30-40%. Though screening by ACOG criteria may have good detection rates but more than two thirds of the population would become screen positive which nullifies this approach as a good screening methodology in low resource settings. Multiparametric approach for screening in first trimester serves as a better screening tool to enable higher detection rate of disease with least false positive rates. Uterine artery Doppler when combined with maternal characteristics and mean arterial pressure could achieve a detection rate of about 60% and would still target only one third of the population for increased antenatal surveillance. This requires training healthcare professionals in the periphery for this approach and this should be our prime focus in the current scenario. Inclusion of serum biochemistry would still bring down the target population to 10% and increase the DR and can be considered as an additional test in economically feasible population. In low resource settings a better screening approach to PE would be a combination of maternal history, biophysical or biochemical parameters whichever is feasible considering the economy and availability of resources.