Early-Term Birth May Increase Risk for Attention-Deficit/Hyperactivity Disorder

Results of a study published in The Journal of Pediatrics supported growing evidence that elective deliveries should be delayed to ≥39 weeks’ gestation to reduce risk for attention-deficit/hyperactivity disorder (ADHD).

This study was a secondary analysis of data from the Fragile Families and Child Wellbeing (FFCWB) study which was a random sample of births with a nonmarital oversample at 75 hospitals in 20 large cities in the United States between 1998 and 2000. At 9 years of age, the children (N=1427) were evaluated by their teachers for ADHD using the Conners Teacher Rating Scale-Revised Short Form (CTRS-R) instrument. Risk for ADHD was related with gestational age (GA) at birth and maternal characteristics.

The children were well balanced for gender (52% boys). The mothers were aged 20-35 years (73%), 48% were Black, 27% were Hispanic, 32% had less than high school education, and this was the first birth for 38%.

The average score for ADHD was 9.24 (SD, 8.84) points, hyperactivity symptom score was 3.65 (SD, 4.72) points, oppositional symptom score was 2.13 (SD, 3.52) points, and cognitive problems or inattention score was 4.53 (SD, 4.16) points.

Stratified by early term (37-38 weeks’ gestation; n=396) and full-term (39-41 weeks’ gestation; n=1031) birth, the early-term children had significantly higher scores for ADHD (mean, 10.57 vs 8.72), hyperactivity (mean, 4.47 vs 3.34), and cognitive problems or inattention (mean, 4.95 vs 4.36).

Risk for ADHD was associated with mother marital status as married (adjusted incidence rate ratio [aIRR], 0.72; P <.01), GA (aIRR, 0.94; P <.01), Medicaid coverage (aIRR, 1.17; P <.05), and male gender (aIRR, 1.74; P <.01).

Hyperactivity was associated with married marital status (aIRR, 0.69; P <.01), GA (aIRR, 0.94; P <.05), Medicaid coverage (aIRR, 1.22; P <.05), and male gender (aIRR, 2.01; P <.01).

Oppositional symptoms were associated with mother being foreign born (aIRR, 0.55; P <.01), college graduate mother (aIRR, 0.61; P <.05), Medicaid coverage (aIRR, 1.38; P <.01), male gender (aIRR, 1.65; P <.01), and non-Hispanic Black ethnicity (aIRR, 1.81; P <.01).

Cognitive problems or inattention were associated with the mother being a college graduate (aIRR, 0.68; P <.01), being married (aIRR, 0.78; P <.01), having some college (aIRR, 0.81; P <.01), GA (aIRR, 0.95; P <.01), Medicaid coverage (aIRR, 1.21; P <.01), and male gender (aIRR, 1.23; P <.01).

In the model using alternative definitions of GA, no associations between GA and symptoms were observed when GA was defined as a continuous variable. Using an early- vs full-term definition, only hyperactivity remained related with early birth (adjusted odds ratio [aOR], 1.51; P <.05).

Data for this study were sourced from urban areas with an oversampling of nonmarried women. Findings may not be generalizable.

Study authors concluded, “The findings from this study highlight the importance of longer gestation and add to mounting evidence based on neonatal, developmental, and educational outcomes that early elective deliveries (<39 weeks) should be avoided. These findings also support the need for regular screenings for ADHD symptoms in children born early-term who might otherwise be overlooked because of their term-birth status.”

This article originally appeared on Psychiatry Advisor