Fetal handedness and head position preference: a developmental study.

Hand-head contacts were observed by means of serial ultrasound recordings in 10 healthy fetuses from 12 to 38 weeks of gestational age. Contacts were distinguished as being unimanual or bimanual, and if unimanual, whether they were made with the right or left hand. Both types of contact and ones made unimanually with the right or left hand were identified at each age as to whether they were associated with a preferential head position. A strong unimanual bias was evident at each age except for Week 36. At this age, there was a bimanual bias. Unimanual contacts did not develop a lateralized preference, and neither type of contact established a stable relationship with head position. Furthermore, there was no evidence to support the suggestion that hand contact and head position codevelop to form a preferred ipsilateral synergy. Findings are discussed relative to contradictory evidence from other fetal and neonatal studies.

Prenatal development of arm posture.

Fetal arm posture was studied longitudinally in 10 uncomplicated pregnancies using real-time ultrasound. Observation were performed at four weekly intervals from 12 to 36 weeks, and at 38 weeks. The percentage of assessments with optimal visualization of elbow, wrist and fingers was 84% at 12 weeks and more than 90% thereafter (range 92-98%). There was a clear developmental trend towards increased flexion. Flexion of the elbow occurred frequently from 12 weeks onwards with an increased incidence at 16 weeks, that in the fingers from 20 weeks onwards and from 28 weeks to term age in the wrist. All three trends were statistically significant. There was considerable intra-individual consistency in terms of the ages at which flexion increased. In fact the increase of flexion occurred one session later in only 6/30 registrations. The combined data of the elbow, wrist and fingers revealed preferential arm posture at 12 weeks with the elbow flexed and the wrist and fingers extended. From 16 to 28 weeks, the predominant posture consisted of elbow flexion, wrist extension and finger flexion and complete flexion thereafter. The development of fetal arm posture does not comply with a proximo-distal trend in that there was first an increase in flexion at the elbow, followed by the fingers and finally the wrist. The implications of our findings for understanding the prenatal development of the central nervous system and subsequent postural adjustments to extrauterine life are discussed.

Automated analysis of antepartum fetal heart rate in relation to fetal rest-activity states: a longitudinal study of uncomplicated pregnancies using the Sonicaid System 8000.

OBJECTIVES: To learn which fetal heart rate (FHR) parameters change with gestational age and to demonstrate the relation with fetal rest-activity states. STUDY DESIGN: FHR and fetal movements were recorded in 12 uncomplicated pregnancies from 26 weeks gestational age onwards. Seventy-two FHR recordings of 60 min duration were analysed by a computer (Sonicaid System 8000). Statistical analysis of complete 60 min recordings and selective periods of rest and activity comprised Spearman's rank correlation test, regression analysis and Wilcoxon's signed-rank test. RESULTS: The time needed to meet the system's criteria of normality decreased with gestational age. The incidence of accelerations (ACC), overall FHR variation (VAR) and variation during 'episodes of high variation' (VEHV) increased with gestational age in the total population, but statistical significance of these relations could only be demonstrated in a minority of individual fetuses. Most FHR parameters differed significantly for periods of fetal rest and activity. No FHR parameters showed a relation with gestational age during periods of rest. CONCLUSIONS: The increase of ACC, VAR and VEHV with gestational age is primarily due to an increase during fetal activity. The considerable variation within and between fetuses, however, can only be partly explained by fetal rest-activity states.

Prenatal head position from 12-38 weeks. II. The effects of fetal orientation and placental localization.

The possible influence of placental localization and fetal orientation on a predominant fetal head position was studied longitudinally in 10 uncomplicated pregnancies from 12 to 38 weeks by means of real-time ultrasound. Throughout gestation, when the fetal vertebral column was oriented to the left side of the mother, head positions to the right and in midline were seen most frequently, whereas a vertebral column to the right was more often associated with a head left position and a head position in midline. These findings support the suggestion that when the fetal vertebral column is in a lateral orientation relative to the mother, one side of the fetal head is more likely to be restricted by the pelvis and backbone of the mother. However, the orientation of the fetal vertebral column does not seem to be a determining factor as the incidence of lateralized head positions increased with age, while the incidence of a vertebral column to the right or left side of the mother remained unchanged. No associations were found between the localization of the placenta and either head position or fetal lie.

Prenatal head position from 12-38 weeks. I. Developmental aspects.

Fetal head position relative to the fetal body was studied longitudinally in 10 uncomplicated pregnancies by means of real-time ultrasound. Registrations were made at 4 weekly intervals from 12 to 36 weeks, and at 38 weeks. The percentage of assessments with optimal visualization of head position for analysis increased with age. The development of head position involved a change from a midline to a lateralized preference. It was only at 38 weeks that a clear lateralized head position was found with the head being held mainly to the right. The degree of intra- and inter-individual variability was considerable, a finding typical of motor behaviour in the healthy fetus. It is hypothesized that this bias is due to neural maturation. The implications of our findings for the subsequent development of hand preference are discussed.

Automated analysis of near-term antepartum fetal heart rate in relation to fetal behavioral states: the Sonicaid System 8000.

Fetal heart rate and fetal movements were recorded in 16 uncomplicated near-term pregnancies. The recordings were used to evaluate a system for automated fetal heart rate analysis (Sonicaid System 8000). Fetal rest-activity patterns were considered in the analysis. The mean duration of C2F periods "active sleep," 33 minutes) was significantly greater than that of C1F periods ("quiet sleep," 19 minutes) (p less than 0.001). The incidence of accelerations and decelerations and the overall fetal heart rate variations were greater during C2F than during C1F (p less than 0.001). In 11 of 16 C1F periods, the system classified the fetal heart rate variation as "questionable" or "abnormal." Episodes of high variation were identified in only 3 of 16 C1F periods, but they were found in all 18 C2F periods. Episodes of low variation were identified in 14 of the 16 C1F periods but were not found in any C2F periods. During C2F periods, the system's criteria of normality were met in all cases but one; they were not met during any of the C1F periods. Thus the diagnosis of fetal distress should not be based merely on the absence of accelerations, low fetal heart rate variation, or absence of episodes of high variation in recordings with a duration of less than 45 minutes.