Variables predicting low infant developmental scores: Maternal age above 30 years is a main predictor

Aim: To explore variables predicting low developmental scores in 6-month-old infants in a population-based study. Methods: In a longitudinal study representative of pregnant women in Oslo, Norway, questionnaires were answered at 17 and 30 weeks of pregnancy and 6 months after term; N = 1053 after exclusions (women with non-Scandinavian ethnicity, twin births, infants <5.0 or >7.0 months corrected age, and birth weight <2.5 kg), and data were collected from the Norwegian Birth Registry. Measures included sociodemographic variables, maternal mental health and pregnancy life style, data concerning the birth/newborn, and the Ages and Stages Questionnaires (ASQ) for 6-month-olds. Logistic regression analyses were used to identify variables predicting an ASQ score 15th percentile. Results: In adjusted analyses, only increasing maternal age and infant having older siblings predicted a low score on ASQ Total. These variables also predicted low scores on several ASQ areas (i.e. Communication, Gross motor, Fine motor, Problem-solving and Personal social), together with maternal major lifetime depression and feeling lonely. Protective variables were increasing infant birth weight (Gross motor) and pregnancy smoking (Communication). Other maternal sociodemographic variables, and infant sex, had no predictive power. Already at a maternal age of 31, the mean age of the pregnant women, the possibility of a low infant score increased significantly. Conclusions: In this population-based study, higher maternal age, having older siblings, and a history of maternal major lifetime depression, mainly predicts low developmental scores in 6-month-old infants.