Prenatal exposure to SARS-CoV-2 raises risk of neurological disorders in infants

By Neha MathurReviewed by Emily Henderson, B.Sc.May 6 2022

In a recent study published in the journal PLOS One, researchers investigated the early indicators of neurological dysfunctions, including the absence of fidgety movements, in three to five-month-old infants prenatally exposed to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Study: Infants prenatally exposed to SARS-CoV-2 show the absence of fidgety movements and are at higher risk for neurological disorders: A comparative study. Image Credit: mentalmind / Shutterstock

All congenital viral infections pose a considerable risk of neurological disorders. Accordingly, SARS-CoV-2 could be detrimental to the health of pregnant women and their neonates. However, the impact of SARS-CoV-2 infection on the central nervous system (CNS) and long-term brain development of infants are not well defined.

Moreover, complications due to minor-to-serious neurological dysfunctions are hard to detect in neonates. So far, only the general movement assessment has effectively identified neurological difficulties early, providing a way for early intervention.

Fidgety movements are the early indicators of general movements in neonates. Abnormal or absent fidgety movements are an early indicator of the future development of neurological dysfunction, especially cerebral palsy.

Additionally, the fidgety movements reflect the ontogeny of general movements. Furthermore, they show the impact on the brain areas involved in motor control, emotional & cognitive control, and the connectivity between multiple brain regions.

About the study

In the present observational study, researchers recruited 56 neonates in the age group of three to five months born in a hospital in Mexico City between May 2020 and March 2021. They were singleton births, born after a gestation period of greater than or equal to 36 weeks and with no congenital or serious illness, such as perinatal asphyxia.

The 28 infants in the exposed group were born to mothers who contracted coronavirus disease 2019 (COVID-19) in the last trimester of pregnancy and had an active infection at the time of delivery. These women had not received any COVID-19 vaccine but at least once tested positive on a reverse transcription-polymerase chain reaction (RT-PCR) test between hospital admission and delivery. Conversely, the 28 infants in the non-exposed group were born to mothers with no history of COVID-19.

The researchers obtained the demographic and medical history of the mother and her newborn from hospital records. They used Prechtl’s method for early motor repertoire assessment that calculated a motor optimality score-revised (MOS-R) value. It is noteworthy that MOS-R values quantified the quality of fidgety movements among other postures apparent at the age of three to five months. The total MOS had two cut-off scores: <24 and <14 for nonoptimal and severely reduced performance, respectively.

Previous studies have shown that a lower total MOS resulted in difficulty in learning in children between four and 10 years of age, and minor neurological dysfunctions in children aged seven to 11 years. Additionally, lower MOS scores translated into lowered intelligence, focus, and motor-visual integration in five to seven-year-old children. However, the neurodevelopmental outcomes were the worst when the total MOS indicated no fidgety movements. The researchers assessed the effect of total MOS on length of hospital stay using Spearman’s rho and the chi-square test for the type of delivery, cesarean and vaginal.

Study findings

In the exposed group, the newborn RT–PCR test results revealed that 86% of infants were SARS-CoV-2-negative, and 11% were positive. Additionally, 11% of infants in the exposed group showed the absence of fidgety movements with a total MOS-R<14 points, and three other infants showed abnormal fidgety movements.

Since these infants had the lowest total MOS-R in the whole sample, they seemed particularly prone to developing neurological disorders. In the non-exposed group, only one infant showed abnormal fidgety movements with a total MOS-R of 15 points.

The atypical body symmetry (p = 0.009) and MOS-R values were significantly lower (Z = -3.08, p = 0.002) in the exposed group; however, the effect size measurements highlighted the magnitude of the difference (Cohen’s d = 0.97).

Additionally, the exposed group had a significantly reduced total MOS-R than the non-exposed group (medians = 21 vs. 23). Although the exposed group had some infants with optimal performance, the average total MOS in both groups indicated a non-optimal performance, with the exposed group having lower performance than the non-exposed group.

Notably, three infants with positive RT–PCR tests scored total MOS-R points of 20, 23, and 26, implying that two infants had a much lowered MOS-R score, and one had an optimal score. These results were consistent with the overall MOS results, highlighting that the lower total MOS in the exposed group was not due to infants with positive RT–PCR tests.

The observed association between total MOS-R and length of hospital stay was (rho (56) = –0.31, p = 0.020). Moreover, there were no differences in total MOS between cesarean and vaginal delivery (t = –0.44, p = 0.663).

Conclusions

The present study highlighted that the adverse effects of SARS-CoV-2 exposure go beyond the pregnant mother and manifest in their infants. Accordingly, some infants in the exposed group showed no fidgety movements at the age of three to five months, indicating an increased risk of developing neurological disorders.

The authors recommended the implementation of follow-up investigations to lessen the consequences of the high risk of developing neurological disorders among infants prenatally exposed to SARS-CoV-2.

Policymakers should also provide adequate information and support to healthcare professionals and parents and consider incorporating low-cost follow-up evaluations for such children.