Table 2.
Descriptions of behaviors coded from ultrasound recordings and the derived composite variables
| Composite Variable | Category of Observation | Observed Behavior | Description |
|---|---|---|---|
| Chest Movements | Hiccup | Consists of a jerky, repetitive contraction of the diaphragm (not included in summary variable). | |
| Breathing Movements | Regular | Displacement of the diaphragm with movement of the abdomen; rhythmic or non-rhythmic. | |
| Vigorous | FBM’s that are large enough to move the entire fetus’ body. | ||
| Mouth Movements | Yawning | The timing of a yawn is similar to a stretch that includes prolonged wide opening of the jaws followed by relaxation; often accompanied by a stretch or a subsequent GBM. | |
| Mouthing Movements | Rhythmic | Rhythmical bursts of jaw opening and closing at least 4 times in 10 seconds (sucking). | |
| NonRhythmic | Mouth opening and closing that is isolated or limited to less than 4 at one time, often with tongue protrusion or lapping (drinking). | ||
| Isolated Movements (IM) | Head Movements | Rotation | Movement of the head in the lateral plane for at least at least a 30 degree angle from starting position. |
| Extension | A small head movement that extends upward in the vertical plane. | ||
| Isolated | Small movement of the head that is not an extension or rotation. | ||
| Limb Movements | Smooth | Movement of an upper or lower extremity that is generally fluid. | |
| Jerky | Movement of an upper or lower extremity that is generally forceful and/or abrupt in nature. | ||
| Indeterminate | Lower limb (occasionally upper limb) movement that is suggested by shift in fetal position but cannot be directly observed. | ||
| Hand to Face | The hand slowly touches the face or mouth. | ||
| Tremor | Small rhythmic, jerky movement of an extremity (or chin). | ||
| Fidgeting | Nearly continuous, repetitive and jerky limb movements that are not part of a GBM or other patterned movement. | ||
| Complex Body Movements (CBM) | General Body Movements (GBM) | Smooth | Simultaneous and coordinated movement of 1+ limbs, trunk and head that is fluid and smooth and results in a change of position. |
| Jerky | Simultaneous and coordinated movement of 1+ limbs, trunk and head that involves jerky movements of limbs or entire body. | ||
| Incomplete | Simultaneous movement of head, trunk and limbs that is not fluid or coordinated and does not result in change in position | ||
| Patterned Body Movements | Stretch | A single event including a back extension or upward movement of the shoulder with retroflexion of the head; typically includes a pause at the peak of the movement with subsequent relaxation. | |
| Backarche | Extension of trunk and maintenance in this position for > 1 second. | ||
| Startle | A quick, generalized movement, involving abduction or extension of the limbs with or without movement of the trunk and head, followed by a return to a resting position. | ||
| Other | Quiescence | Absence of all body movements other than FBM or mouthing. | |
| Fetal Quality of Movement (FQM) | A mean summary score of overall movement quality (1-5 scale) derived from scored frequencies of 5 categories of coded behaviors; highest scores indicate overall rest-activity balance, maturity of smooth movements, and absence of startles and tremors. | ||
| FQM-Quiescence | 1-5 score; median %ile score=5, while lowest and highest % = 1. | ||
| FQM-Fetal Movement | 1-5 score; median %ile score=5, while lowest and highest % = 1. | ||
| FQM-Jerky Movements | 1-5 score; Lowest %=5, Median %=3, Highest=1. | ||
| FQM-Tremors | 1-5 score; Lowest %=5, Median %=3, Highest=1. | ||
| FQM-Startles | 1–5 score; Lowest %=5, Median %=3, Highest=1. | ||
NOTE: Observed fetal behaviors that are bolded comprise the associated composite variable.