Background: Neonatal interventions are largely focused on reduction of mortality and progression towards Millennium Development Goal 4 (child survival). However, little is known about the global burden of long-term consequences of intrauterine and neonatal insults. We did a systematic review to estimate risks of long-term neurocognitive and other sequelae after intrauterine and neonatal insults, especially in low-income and middle-income countries.

Methods: We searched Medline, Cumulative Index to Nursing and Allied Health Literature, the Cochrane Library, and Embase for studies published between Jan 1, 1966, and June 30, 2011, that reported neurodevelopmental sequelae after preterm or neonatal insult. For unpublished studies and grey literature, we searched Dissertation Abstracts International and the WHO library. We reviewed publications that had data for long-term outcome after defined neonatal insults. We summarised the results with medians and IQRs, and calculated the risk of at least one sequela after insult.

Findings: Of 28,212 studies identified by our search, 153 studies were suitable for inclusion, documenting 22,161 survivors of intrauterine or neonatal insults. The overall median risk of at least one sequela in any domain was 39·4% (IQR 20·0-54·8), with a risk of at least one severe impairment in any insult domain of 18·5% (7·7-33·3), of at least one moderate impairment of 5·0% (0·0-13·3%), and of at least one mild impairment of 10·0% (1·4-17·9%). The pooled risk estimate of at least one sequela (weighted mean) associated with one or more of the insults studied (excluding HIV) was 37·0% (95% CI 27·0-48·0%) and this risk was not significantly affected by region, duration of the follow-up, study design, or period of data collection. The most common sequelae were learning difficulties, cognition, or developmental delay (n=4032; 59%); cerebral palsy (n=1472; 21%); hearing impairment (n=1340; 20%); and visual impairment (n=1228; 18%). Only 40 (26%) studies included data for multidomain impairments. These studies included 2815 individuals, of whom 1048 (37%) had impairments, with 334 (32%) having multiple impairments.

Interpretation: Intrauterine and neonatal insults have a high risk of causing substantial long-term neurological morbidity. Comparable cohort studies in resource-poor regions should be done to properly assess the burden of these conditions, and long-term outcomes, such as chronic disease, and to inform policy and programme investments.

Funding: The Bill & Melinda Gates Foundation, Saving Newborn Lives, and the Wellcome Trust.