ObjectiveTo evaluate neuromotor repertoires and developmental milestones in infants exposed to antenatal COVID-19.DesignLongitudinal cohort study.SettingHospital-based study in Los Angeles, USA and Rio de Janeiro, Brazil between March 2020 and December 2021.ParticipantsInfants born to mothers with COVID-19 during pregnancy and prepandemic control infants from the Graz University Database.InterventionsGeneral movement assessment (GMA) videos between 3 and 5 months post-term age were collected and clinical assessments/developmental milestones evaluated at 6–8 months of age. Cases were matched by gestational age, gender and post-term age to prepandemic neurotypical unexposed controls from the database.Main outcome measuresMotor Optimality Scores Revised (MOS-R) at 3–5 months. Presence of developmental delay (DD) at 6–8 months.Results239 infants were enrolled; 124 cases (83 in the USA/41 in Brazil) and 115 controls. GMA was assessed in 115 cases and 115 controls; 25% were preterm. Median MOS-R in cases was 23 (IQR 21–24, range 9–28) vs 25 (IQR 24–26, range 20–28) in controls, p<0.001. Sixteen infants (14%) had MOS-R scores <20 vs zero controls, p<0.001. At 6–8 months, 13 of 109 case infants (12%) failed to attain developmental milestones; all 115 control infants had normal development. The timing of maternal infection in pregnancy (first, second or third trimester) or COVID-19 disease severity (NIH categories asymptomatic, mild/moderate or severe/critical) was not associated with suboptimal MOS-R or DD. Maternal fever in pregnancy was associated with DD (OR 3.7; 95% CI 1.12 to 12.60) but not suboptimal MOS-R (OR 0.25; 95% CI 0.04 to 0.96).ConclusionsCompared with prepandemic controls, infants exposed to antenatal COVID-19 more frequently had suboptimal neuromotor development.