Developmental trajectories of general and breathing movements in fetal twins

Intrauterine twin environment and genetic factors subliminally affecting general movements in preterm infants

BACKGROUND

Understanding background factors is beneficial for interpreting general movements (GMs). This study examines the factors involved in preterm-writhing GMs by comparing twins and singletons.

METHOD

The subjects were 107 infants cared for at Oita University. The cohort consisted of very-low-birth-weight infants, including twins with a birth weight < 2000 g. The median gestational age (GA) was 29 weeks 1 day. The subjects consisted of 75 singletons, 32 twins (16 pairs), 20 monochorionic twins (M-twins), and 12 dichorionic twins (D-twins). GMs were scored according to the GMs optimality score (GMOS) and integrated into 6 items: the quality, neck-trunk and space, amplitude-speed, rotation, onset-offset and cramped, and tremulous score at 32-34 weeks, 35-36 weeks, and 37-42 weeks' GA. A hierarchical cluster analysis was performed using integrated GMOS, and the characteristics of clusters were examined according to clinical backgrounds.

RESULTS

Three clusters were identified. Cluster 1 was characterized by good-quality GMs, cluster 2 by a poor repertoire but optimal space and rotatory components, and cluster 3 by overall poor-quality GMs, respectively. The mean GMOSs were 36.6, 31.8 and 24.3 in clusters 1, 2, and 3, respectively. There were no marked differences in proportions within clusters with respect to sex and twins. Small-for-gestational age (SGA) was significantly more frequent in cluster 3 at 32-34 weeks' GA than in other clusters. Perinatal brain injury had a significantly lower proportion in cluster 1 and a higher proportion in cluster 3 at 35-36 weeks' GA and 37-42 weeks' GA. M-twin pairs tended to belong to the same clusters at 35-36 weeks' GA.

CONCLUSION

Preterm writhing GMs are associated with SGA and perinatal brain injury. Cluster matching in M-twins suggests that certain genetic factors may substantially influence GMs.

Fetal movements: the origin of human behaviour

The study of the onset and ontogeny of human behaviour has made it clear that a multitude of fetal movement patterns are spontaneously generated, and that there is a close association between activity and the development of peripheral and central structures. The embryo starts moving by 7.5 week's gestation; 2 to 3 weeks later, a number of movement patterns including general movements, isolated limb and head movements, hiccup, and breathing movements, appear. Some movements (e.g. yawning, smiling, 'pointing'; we show these in eight videos in this review) precede life-long patterns; others have intrauterine functions, such as sucking/swallowing for amniotic fluid regulation, breathing movements for lung development, or eye movements for retinal cell diversity. In cases of developmental brain dysfunction, fetal general movements alter their sequence and gestalt, which suggests a dysfunction of the developing nervous system. The scarcity of longitudinal studies calls for further comprehensive research on the predictive value of prenatal functional deviations. What this paper adds Motor output can occur in the absence of sensory input. Structural development is activity-dependent. Fetal general movements are among the first movement patterns to occur. Pregnancy-related and maternal factors impact quantity and modulation of fetal general movements. Prenatal general movement assessment has not yet brought the expected breakthrough.

Justifying Separate Experiences for Twins: Dorothy Burlingham's Classic Twin Study/Twin Research Reviews: Monozygotic Twins with Maturity-Onset Diabetes, Gene Editing of Chinese Twins, Educational Disadvantage of Early-Born Twins and Developmental Trajectories of Movements in Fetal Twins/In the News: Twins with Nearly Identical License Plates, Rare Case of Fetus-in-Fetu, Twin Brothers Killed at Pearl Harbor, Death of a 96-Year-Old Twin Holocaust Survivor, Death of Male-Female Twin Toddlers in a Heated Car and Confusion of Identical Twin Politicians

This article explores the justification for providing separate experiences for twins. The focus is on Dorothy Burlingham's (1952; Twins: A study of three sets of identical twins with 30 charts. London, UK: Imago) classic, in-depth study of three identical twin-pairs. Implications for how twins are raised currently will be examined. Reviews are presented of twin research concerning monozygotic twins with maturity-onset diabetes, gene editing of fetal Chinese twins, educational disadvantage of early-born twins, and developmental trajectories of twins' prenatal movements. Some unusual experiences and situations involving twins that warrant media attention are also summarized. They include twins with nearly identical license plates, a rare case of fetus-in-fetu, twin brothers killed at Pearl Harbor, the death of a 96-year-old twin Holocaust survivor, the accidental death of male-female twin toddlers in a heated car and confusion over identical twin politicians.