Incomplete antenatal steroid course tied to neurodevelopmental impairment in preemies
Neurodevelopmental impairment (NDI) is common among preterm very-low birth weight (PT/VLBW) infants, according to a recent Singapore study, which additionally reports that the male sex and lack of antenatal steroids (ANS) are risk factors for delayed cognitive skills.
“The aim of the study was to evaluate the neurodevelopmental outcome of PT/VLBW infants at 2 years corrected age, born at Singapore’s largest tertiary perinatal centre, and identify the perinatal, neonatal and environmental risk factors associated with signiﬁcant developmental delay and neurosensory impairment,” said researchers.
The median composite scores for the cognitive, language and motor domains of the 3rd edition of the Bayley Scales of Infant and Toddler Development (Bayley-III) were 94, 89 and 95, respectively. [J Perinatol 2018;doi:10.1038/s41372-018-0138-3]
Significant delays in the corresponding subscales were observed in 6 percent, 18 percent and 5 percent of the study cohort. Four percent of the participants had cerebral palsy, while 2 percent were deaf. There were no cases of blindness reported.
NDI was observed in 20 percent of the children overall, while 70 percent had normal assessment results and were defined to be without neurosensory impairments.
The fully adjusted logistic regression model showed that significant risk factors for delayed cognitive skills included the male sex (odds ratio [OR], 22.4; 95 percent CI, 1.5–341.1; p=0.025), lack of complete ANS course (OR, 41.5; 3.5–485.7; p=0.003) and hypotension requiring inotropes (OR, 36.0; 2.6–506.0; p=0.008).
On the other hand, lower maternal education (OR, 3.8; 1.4–10.3; p=0.10), lack of ANS (OR, 2.8; 1.1–7.4; p=0.04) and 5-minute Apgar score ≤5 (OR, 7.4; 1.4–38.4; p=0.017) were correlated with delayed language skills. A higher risk of delayed motor skills significantly correlated with chronic lung disease at 36 weeks (OR, 38.3; 2.4–603.4; p=0.01).
In terms of NDI in general, the use of postnatal steroids (OR, 3.36; 1.07–10.54; p=0.04) and failure to complete a full course of ANS (OR, 2.91; 1.21–7.00; p=0.02) were determined as significant risk factors.
“ANS are currently recommended as the standard of care in the management of women with possible preterm delivery <34 weeks,” explained researches, noting that while it has been shown that ANS protects against major neonatal morbidities, the long-term benefits remain unclear.
“The reasons for the protective effect of ANS have been postulated to be both a direct effect of improved brain maturation, reduced blood–brain barrier permeability or indirectly mediated by a decrease in neonatal morbidities especially severe brain injury or reduction in ventilator need,” they said. [JAMA Pediatr 2016;170:1164-1172; Am J Physiol 1999;276:R283-R289]
For the present study, researchers recruited 165 PT/VLBW infants (median gestational age 28 weeks; 46 percent male) from the KK Women’s and Children’s Hospital in Singapore. NDI assessment was performed using the Bayley-III and was defined as the presence of neurosensory impairments or a Bayley-III score <70 in any domain.
The present study has important limitations such as a high attrition rate, the lack of individual data on the quality of perinatal care, the lack of healthy and full-term controls, and the single-centre design, all of which inhibit the strength of the conclusions and the generalizability of the findings.
“However, our hospital is the largest referral tertiary perinatal centre in Singapore and manages more than two-thirds of extremely preterm births in the country,” said researchers.
“Risk factors for both NDI and individual domain delay were identiﬁed and will be helpful in planning of speciﬁc and targeted early intervention services. The cohort will continue to be followed up and re-evaluated at 5.5 years before school entry,” they added.