Added prognostic value of Doppler ultrasound for adverse perinatal outcomes: A pooled analysis of three cohort studies.

BACKGROUND: Fetal growth restriction (FGR) is an obstetric complication associated with adverse perinatal outcomes. Doppler ultrasound can improve perinatal outcomes through monitoring at-risk fetuses and helping time delivery. AIM: To investigate the prognostic value of different Doppler ultrasound measurements for adverse perinatal outcomes. MATERIALS: Individual participant data. METHODS: We performed a pooled analysis on individual participant data. We compared six prognostic models using multilevel logistic regression, where each subsequent model added a new variable to a base model that included maternal characteristics. Estimated fetal weight (EFW) and four Doppler ultrasound measurements were added in turn: umbilical artery pulsatility index (UA PI), middle cerebral artery pulsatility index (MCA PI), cerebroplacental ratio (CPR), and mean uterine artery pulsatility index (mUtA PI). The primary outcome was a composite adverse perinatal outcome, defined as perinatal mortality, emergency caesarean delivery for fetal distress, or neonatal admission. Discriminative ability was quantified with area under the curve (AUC). RESULTS: Three data sets (N = 3284) were included. Overall, the model that included EFW and UA PI improved AUC from 0.650 (95% CI 0.624-0.676) to 0.673 (95% CI 0.646-0.700). Adding more ultrasound measurements did not improve further the discriminative ability. In subgroup analysis, the addition of EFW and UA PI improved AUC in both preterm (AUC from 0.711 to 0.795) and small for gestational age pregnancies (AUC from 0.729 to 0.770), but they did not improve the models in term delivery or normal growth subgroups. CONCLUSIONS: Umbilical artery pulsatility index added prognostic value for adverse perinatal outcomes to the already available information, but the combination of other Doppler ultrasound measurements (MCA PI, CPR or UtA PI) did not improve further prognostic performance.

Publication bias may exist among prognostic accuracy studies of middle cerebral artery Doppler ultrasound.

OBJECTIVES: The objective of this study was to assess if there is evidence of publication bias in prognostic accuracy studies of middle cerebral artery (MCA) or cerebroplacental ratio (CPR) for adverse perinatal outcome. STUDY DESIGN AND SETTING: We queried PubMed, EMBASE, the Cochrane Library, and ClinicalTrials.gov and searched abstract books of five perinatal conferences (1989-2017). We included prognostic accuracy studies on MCA and/or CPR. Highest reported accuracy estimates, sample size, study design, and conclusion positivity were extracted and compared. RESULTS: We included 127 full-text articles and 51 conference abstracts, 29 of which had not been reported as full-text article. In conference abstracts not reported in full, median negative predictive value was significantly lower compared to full-text articles (0.79 [interquartile range 0.67-0.97] vs. 0.95 [0.89-0.99]; P < 0.001). No significant difference was identified for positive predictive value (0.62 vs. 0.59; P = 0.827), sensitivity (0.67 vs. 0.71; P = 0.159), and specificity (0.86 vs. 0.86; P = 0.632). Study design differed significantly as well (P = 0.030), with fewer prospective studies in conference abstracts not reported in full compared to full-text articles (28% vs. 54%). We found no significant differences in sample size or conclusion positivity. CONCLUSION: Possibly, a publication bias in previously published meta-analyses of MCA and CPR has led to overly generous estimates of prognostic performance.

Women's experiences of monitoring the small-for-gestational age fetus by ultrasound: A qualitative study.

OBJECTIVE: To explore experiences among pregnant women diagnosed with a small-for-gestational age (SGA) fetus, and monitored by frequent ultrasounds. METHODS: We performed a qualitative study at the outpatient clinic of the Gynecology and Obstetrics department of a large academic hospital in Amsterdam. Semi-structured interviews were conducted with fifteen women, diagnosed with an SGA fetus during their pregnancy and having had at least two monitoring ultrasounds since. Themes were identified following analysis of the interview transcripts. RESULTS: Most women experienced the frequent ultrasounds as a source of support providing comfort and a feeling of safety. It was considered necessary, in the best interest of the baby, which outweighed the discomfort caused by having to come to the hospital frequently. Women described anxiety building up prior to each ultrasound, but feeling reassured and relieved afterwards. During the ultrasound a continuous explanation was preferred, which provided confirmation and a feeling of security. Women identified the uncertainty of SGA's cause and prognosis as one of the biggest challenges to cope with, for which they used different strategies. Many women expressed a need for more detailed information and counselling, including non-medical aspects of pregnancy and delivery as well. Lastly, many women reported that seeing different doctors negatively influenced the perceived quality of care. CONCLUSIONS: In general, women in this study were satisfied with the ultrasounds for their small-for-gestational age pregnancies. However, women expressed a need for additional information to help cope with a feeling of uncertainty regarding cause and prognosis. Their medical team should preferably provide this in a consistent and continuous manner.

Doppler measurements of both umbilical arteries do not improve predictive value for adverse perinatal outcomes in small-for-gestational age fetuses.

OBJECTIVE: To assess agreement of Doppler ultrasound measurements of the two umbilical arteries in small-for gestational age (SGA) fetuses, and to compare discriminative ability between the two arteries for adverse perinatal outcome. STUDY DESIGN: We analysed a prospective cohort of singleton SGA pregnancies, in which the pulsatility index (PI) of both umbilical arteries was standardly measured by Doppler ultrasound in the free-floating umbilical cord. The outcome of interest was a composite adverse outcome, defined as perinatal death, Apgar score <7 at 5 min, cesarean section for fetal distress, and neonatal intensive care unit admission. RESULTS: A total of 531 measurements were performed in 124 patients. Mean absolute difference between PI measured in the two umbilical arteries was 0.14 (95% CI: 0.12 to 0.15), showing good agreement with an ICC of 0.830 (95% CI: 0.801 to 0.854). Perinatal outcomes were available for 101 patients, of which 48 patients (48%) had a composite adverse perinatal outcome. We found no significant differences between AUCs for prediction of an adverse outcome based on lowest, highest and mean PI values in the two umbilical arteries (AUCs = 0.75, 0.74, 0.75 with p = 0.91). As a comparison, the AUC of a PI value obtained in a single, randomly selected umbilical artery was 0.74. CONCLUSION: The two umbilical arteries show good agreement in terms of their PI values in the free-floating umbilical cord, and do not differ in terms of their discriminative ability for adverse perinatal outcome in SGA fetuses. We found no evidence of an added value of standard Doppler measurement of both umbilical arteries.