Do early intervention programmes improve physical and mental development in babies born too early?

Key messages

Early intervention programmes given to babies born too early may improve mental and physical development in infancy (zero to three years) and do improve mental development at preschool age (three to five years).

There is a lack of good-quality evidence for mental and physical development at school age (five to less than 18 years).

Future research in this area should focus on whether interventions in the first year of life are of benefit as children grow older.

Why do babies born early need interventions?

Babies born too early (before 37 weeks of pregnancy) are more likely to have developmental problems, such as delays in thinking and learning abilities (mental development), or delays in sitting, walking and/or using their hands (physical development).

What are early intervention programmes?

Early developmental interventions aim to reduce mental and physical developmental problems in babies born too early by providing activities to support and improve development. Interventions may focus on the baby, the parent-baby relationship, or a combination of these, and can include different forms of physical and psychological therapy, as well as education.

What did we want to find out?

We wanted to find out if giving early developmental interventions to babies born too early improved their mental and physical abilities throughout childhood.

We also wanted to find out if different types of intervention were better than others. For example:

- when the intervention started, in the hospital or at home;

- what the intervention focused on: the parent, the baby, the parent-baby relationship or a combination;

- whether having a brain injury influenced the effects of early intervention;

- whether the age and weight of the baby at birth influenced the effects of early intervention.

What did we do?
This review was an update from a previous review completed in 2015.

We searched for studies where babies born too early (less than 37 weeks of age) were assigned randomly into a treatment group that provided early developmental intervention, or a control group that received standard follow-up care, which is the typical medical follow-up for preterm babies, and where there was sometimes some more information about caring for babies born early. The intervention could start while the baby was in hospital, but there also had to be intervention that continued at home. The study had to measure the babies’ mental or physical development, or both, after the intervention, and we grouped the age of measurement into three groups: infancy (zero to three years), preschool age (three to five years) and school age (five to less than 18 years).

We compared and summarised the results of the studies and rated our confidence in the evidence based on factors such as the study method, the number of babies in each study, and how many were assessed after the intervention.

What did we find?

We found that aspects of the studies varied a lot regarding the duration of the intervention, the ages of the babies in the study, the length of follow-up, and what the intervention focused on.

There were 44 studies in this review involving 5051 babies who were born too early. There were 19 new studies included in this update and three studies we previously included that had new data.

We found that most of the interventions were focused on both the baby and the parent-baby relationship.

We also found that early developmental interventions improve mental development at preschool age, while they probably did not improve motor outcomes at preschool age. At infant age, our study showed that interventions may improve mental and physical development. They do not, however, benefit mental and physical development at school age.

What are the limitations of the evidence?

There was a lot of variation in aspects of the studies, in particular, how long the interventions lasted and how much intervention infants were given. There was also a range of different measurement tools used to measure development in each age group, particularly for physical development. We have limited confidence in the results at school age follow-up because of concerns about the small number of studies with data.

How up to date is this evidence?

This review updates our previous review from 2015. The evidence is up to date until July 2023.

Authors' conclusions: 

Early developmental intervention programmes for preterm infants probably improve cognitive and motor outcomes during infancy (low-certainty evidence) while, at preschool age, intervention is shown to improve cognitive outcomes (high-certainty evidence). Considerable heterogeneity exists between studies due to variations in aspects of the intervention programmes, the population and outcome measures utilised. Further research is needed to determine which types of early developmental interventions are most effective in improving cognitive and motor outcomes, and in particular to discern whether there is a longer-term benefit from these programmes.

Read the full abstract...

Infants born preterm are at increased risk of cognitive and motor impairments compared with infants born at term. Early developmental interventions for preterm infants are targeted at the infant or the parent-infant relationship, or both, and may focus on different aspects of early development. They aim to improve developmental outcomes for these infants, but the long-term benefits remain unclear. This is an update of a Cochrane review first published in 2007 and updated in 2012 and 2015.


Primary objective

To assess the effect of early developmental interventions compared with standard care in prevention of motor or cognitive impairment for preterm infants in infancy (zero to < three years), preschool age (three to < five years), and school age (five to < 18 years).

Secondary objective

To assess the effect of early developmental interventions compared with standard care on motor or cognitive impairment for subgroups of preterm infants, including groups based on gestational age, birthweight, brain injury, timing or focus of intervention and study quality.

Search strategy: 

We searched CENTRAL, MEDLINE, Embase, CINAHL, PsycINFO and trial registries in July 2023. We cross-referenced relevant literature, including identified trials and existing review articles.

Selection criteria: 

Studies included randomised, quasi-randomised controlled trials (RCTs) or cluster-randomised trials of early developmental intervention programmes that began within the first 12 months of life for infants born before 37 weeks' gestational age (GA). Interventions could commence as an inpatient but had to include a post discharge component for inclusion in this review. Outcome measures were not prespecified, other than that they had to assess cognitive outcomes, motor outcomes or both. The control groups in the studies could receive standard care that would normally be provided.

Data collection and analysis: 

Data were extracted from the included studies regarding study and participant characteristics, timing and focus of interventions and cognitive and motor outcomes. Meta-analysis using RevMan was carried out to determine the effects of early developmental interventions at each age range: infancy (zero to < three years), preschool age (three to < five years) and school age (five to < 18 years) on cognitive and motor outcomes. Subgroup analyses focused on GA, birthweight, brain injury, time of commencement of the intervention, focus of the intervention and study quality. We used standard methodological procedures expected by Cochrane to collect data and evaluate bias. We used the GRADE approach to assess the certainty of evidence.

Main results: 

Forty-four studies met the inclusion criteria (5051 randomly assigned participants). There were 19 new studies identified in this update (600 participants) and a further 17 studies awaiting outcomes. Three previously included studies had new data. There was variability in the focus and intensity of the interventions, participant characteristics, and length of follow-up. All included studies were either single or multicentre trials and the number of participants varied from fewer than 20 to up to 915 in one study. The trials included in this review were mainly undertaken in middle- or high-income countries. The majority of studies commenced in the hospital, with fewer commencing once the infant was home. The focus of the intervention programmes for new included studies was increasingly targeted at both the infant and the parent-infant relationship. The intensity and dosages of interventions varied between studies, which is important when considering the applicability of any programme in a clinical setting.

Meta-analysis demonstrated that early developmental intervention may improve cognitive outcomes in infancy (developmental quotient (DQ): standardised mean difference (SMD) 0.27 standard deviations (SDs), 95% confidence interval (CI) 0.15 to 0.40; P < 0.001; 25 studies; 3132 participants, low-certainty evidence), and improves cognitive outcomes at preschool age (intelligence quotient (IQ); SMD 0.39 SD, 95% CI 0.29 to 0.50; P < 0.001; 9 studies; 1524 participants, high-certainty evidence). However, early developmental intervention may not improve cognitive outcomes at school age (IQ: SMD 0.16 SD, 95% CI -0.06 to 0.38; P = 0.15; 6 studies; 1453 participants, low-certainty evidence). Heterogeneity between studies for cognitive outcomes in infancy and preschool age was moderate and at school age was substantial. Regarding motor function, meta-analysis of 23 studies showed that early developmental interventions may improve motor outcomes in infancy (motor scale DQ: SMD 0.12 SD, 95% CI 0.04 to 0.19; P = 0.003; 23 studies; 2737 participants, low-certainty evidence). At preschool age, the intervention probably did not improve motor outcomes (motor scale: SMD 0.08 SD, 95% CI -0.16 to 0.32; P = 0.53; 3 studies; 264 participants, moderate-certainty evidence). The evidence at school age for both continuous (motor scale: SMD -0.06 SD, 95% CI -0.31 to 0.18; P = 0.61; three studies; 265 participants, low-certainty evidence) and dichotomous outcome measures (low score on Movement Assessment Battery for Children (ABC) : RR 1.04, 95% CI 0.82 to 1.32; P = 0.74; 3 studies; 413 participants, low-certainty evidence) suggests that intervention may not improve motor outcome.

The main source of bias was performance bias, where there was a lack of blinding of participants and personnel, which was unavoidable in this type of intervention study. Other biases in some studies included attrition bias where the outcome data were incomplete, and inadequate allocation concealment or selection bias. The GRADE assessment identified a lower certainty of evidence in the cognitive and motor outcomes at school age. Cognitive outcomes at preschool age demonstrated a high certainty due to more consistency and a larger treatment effect.