Completion of Fetal Anatomy Evaluations in Women With Body Mass Index ≥ 50 kg/m2.

OBJECTIVES: As maternal body mass index (BMI) increases, fetal anatomy ultrasound becomes more challenging, less sensitive, and less likely to be complete. We sought to report our experience of incomplete evaluation of anatomy in patients with BMI of 50 kg/m2 or greater. METHODS: This is a retrospective cohort of singleton gestations in mothers with BMI of 50 kg/m2 or greater, undergoing anatomy evaluations between 2017 and 2021 at 9 maternal-fetal-medicine sites in Houston, TX. Patient variables and scan results were collected throughout pregnancy to provide a longitudinal assessment of the primary outcome, completion rate (percent of all scans which optimally captured 24 American Institute of Ultrasound in Medicine-recommended images). Secondary outcomes included the rate of optimal capture of each individual structure. RESULTS: In total, 293 patients with BMI ≥50 kg/m2 were identified. Only 28% of initial scans were complete, but over the entire pregnancy, a complete anatomic evaluation was achieved in 76% of women, largely due to weekly ultrasounds done for antenatal testing later in pregnancy. Neither BMI, placental location, nor amniotic fluid volume affected completion rate. The most difficult views are the outflow tracts, 4-chamber view, and spine. CONCLUSIONS: One quarter of women with BMI of 50 kg/m2 or greater will not have a complete fetal anatomic evaluation by the end of pregnancy, since even basic fetal anatomic views are technically challenging to complete. Solutions deserve further attention, and may include first trimester imaging, transvaginal imaging, and optimization of ultrasound machine settings.

Identification of newborns with birthweight ≥ 4,500g: Ultrasound within one- vs. two weeks of delivery.

OBJECTIVE: Our objective was to compare the diagnostic characteristics of sonographic estimated fetal weight (SEFW) done within 7 versus 8-14 days before delivery for detection of fetal macrosomia (birthweight ≥ 4500 g). STUDY DESIGN: We performed a multicenter, retrospective cohort study of all non-anomalous singletons with SEFW ≥ 4000 g by Registered Diagnostic Medical Sonographers conducted within 14 days of delivery. Cohorts were grouped by time interval between ultrasound and delivery: 0-7 days versus 8-14 days. The detection rate (DR) and false positive rate (FPR) for detection of birthweight (BW) ≥ 4500 g were compared between groups with subgroup analysis for diabetic women. Area under the receiver operator curve (AUC) was calculated to analyze all possible SEFW cutoffs within our cohort. RESULTS: A total of 330 patients met inclusion criteria with 250 (75.8 %) having SEFW within 7 days and 80 (24.2 %) with SEFW 8-14 days prior to delivery. The rate of macrosomia was 15.1 % (N = 51). The DR for macrosomia was significantly higher when SEFW was performed within 7 days of delivery compared to 8-14 days among non-diabetic (73.0 % vs 7.1 %; p < 0.001) and diabetic women (76.5 % vs 16.7 %; p = 0.02). There was no significant change in FPR in either group. The AUC for detection of macrosomia was significantly higher when SEFW was performed within 7 days versus 8-14 days (0.89 vs 0.63; p < 0.01). CONCLUSION: With SEFW ≥ 4000 g, the detection of BW ≥ 4500 g is significantly higher when the sonographic examination is within 7 days of birth irrespective of maternal diabetes.