Maternal Recognition of Ultrasound-Observed Fetal Movements Among Pregnancies in the Third Trimester: Concordance, Directional Discrepancies, and Associated Factors

Background and Objectives: Maternal perception of fetal movement is widely used to monitor fetal activity; however, maternally perceived movements may not correspond directly to movements observed by ultrasonography. This study aimed to quantify same-window maternal recognition of ultrasound-observed fetal movements, characterize temporal concordance and directional discrepancies, and examine associated maternal and pregnancy-related factors. Materials and Methods: Pregnant women at ≥28 weeks of gestation underwent simultaneous 20 min fetal-movement assessment using real-time ultrasonography and maternal button-press reporting. The ultrasound observer pressed a designated button whenever fetal movement was visually observed, while participants independently pressed a separate button whenever they perceived fetal movement. Both responses were electronically timestamped using the same system clock and segmented into consecutive 5 s windows. Windows containing an ultrasound-observer button press were classified as ultrasound-positive, and those accompanied by a maternal response within the corresponding window were classified as temporally matched. Same-window maternal recognition was defined as the proportion of ultrasound-positive windows accompanied by a maternal response within the same 5 s analytical window. Associated factors were examined using fractional logistic regression with robust standard errors. Results: A total of 112 valid assessment sessions were analyzed. The median number of ultrasound-positive windows was 26.5 (IQR, 15.5–41.5), compared with 10.5 (IQR, 6.0–18.5) maternal-response windows. Median same-window maternal recognition was 20.3% (IQR, 8.3–38.5%; bootstrap percentile 95% CI, 15.7–23.1%), and median overall temporal concordance was 16.1% (IQR, 7.4–25.3%). Maternal-response window counts were lower than ultrasound-positive window counts in 101 of 112 assessment sessions (90.2%). After adjustment for maternal age, BMI, and fetal presentation, later gestational age was associated with lower same-window maternal recognition (β = −0.063, 95% CI −0.122 to −0.004; p = 0.037), corresponding to an average marginal effect of −1.12 percentage points per week (95% CI −2.15 to −0.09; p = 0.033). Conclusions: Maternal and ultrasound-observed fetal-movement counts showed limited same-window temporal correspondence during the 20 min observation period. A modest inverse association with gestational age was observed in the primary model, although the association was less precise in the denominator-aware and vertex-only sensitivity analyses. These findings reflect temporal matching under the predefined 5 s analytical framework and should not be interpreted as indicating that mothers perceive only a small proportion of fetal movements or that maternal perception becomes less reliable as pregnancy advances.