Prenatal syphilis exposure and motor repertoire during the fidgety movements period: a prospective cohort study

To examine the association between prenatal syphilis exposure and the Motor Optimality Score-Revised (MOS-R), comparing exposed and unexposed infants at 12-15 weeks post-term age.

This prospective matched cohort study included 60 infants (37.9 ± 4.2 weeks of gestation) classified into a prenatally syphilis-exposed group (n = 24) and an unexposed control group (n = 36). Infants were assessed between 12 and 15 (13.8 ± 1.1) weeks post-term, according to Prechtl's General Movements Assessment (GMA) standards. The MOS-R was used to assess the quality of fidgety movements (FMs) and the concurrent motor repertoire, including movement and postural patterns and movement character. Assessors were blinded to group allocation and clinical history. Between-group differences were assessed using the Mann-Whitney and chi-square/Fisher's exact-tests; multivariable regression models adjusted for covariates were used to account for potential confounding.

Syphilis-exposed infants showed significantly lower MOS-R scores compared to controls (p = 0.02), with differences attributed to reduced scores in FM (p < 0.01) and movement character (p = 0.01). After adjustment for covariates, prenatal syphilis exposure was associated with reductions of 4.62 and 2.92 points in mean MOS-R and FM scores, respectively, compared with unexposed controls (p's < 0.01). Aberrant FM patterns occurred exclusively among exposed infants.

Prenatal syphilis exposure was associated with lower MOS-R scores, driven by a higher frequency of aberrant FM and altered movement character during the FM period. These findings suggest early neuromotor vulnerability, even in the absence of apparent neurological signs, and may reflect subtle alterations in early neurodevelopment that may not be evident on routine clinical assessment.