Intellectual disability: population‐based estimates of the proportion attributable to maternal alcohol use disorder during pregnancy

Aim The aim of this study was to examine the association between maternal alcohol use disorder and intellectual disability in children. Method All mothers with an International Classification of Diseases (ICD) 9 and/or 10 alcohol‐related diagnosis, a proxy for alcohol use disorder, recorded on the Western Australian health, mental health, and drug and alcohol data sets were identified through the Western Australian Data Linkage Unit (n=5614 non‐Aboriginal; n=2912 Aboriginal). A comparison cohort of mothers without an alcohol‐related diagnosis was frequency matched on maternal age within maternal Aboriginal status and year of birth of their children. Linkage with the Western Australian Midwives Notification System (1983–2001) identified all births to these mothers (n=10 664 and 7907 respectively). Linkage to the Western Australian Intellectual Disability Database and Register of Developmental Anomalies identified cases of intellectual disability with no identified genetic origin (intellectual disability) (n=1487) and fetal alcohol syndrome (n=66). Odds ratios (ORs) and 95% confidence intervals (CIs) for intellectual disability were calculated using logistic regression incorporating generalized estimating equations and used to estimate population‐attributable fractions. Results At least 3.8% (95% CI 2.84–4.89%) of cases of intellectual disability could be avoided by preventing maternal alcohol use disorder: 1.3% (95% CI 0.81–1.86%) in non‐Aboriginal and 15.6% (95% CI 10.85–20.94%) in Aboriginal children. We observed a three‐fold increase in the adjusted odds of intellectual disability in children of mothers with an alcohol‐related diagnosis recorded during pregnancy (non‐Aboriginal OR 2.89, 95% CI 1.62–5.18; Aboriginal OR 3.12, 95% CI 2.13–4.56), with a net excess proportion of 3.7% and 5.5% respectively. One‐third (32%) of children diagnosed with fetal alcohol syndrome had intellectual disability. Interpretation Maternal alcohol use disorder is the leading known risk factor for intellectual disability with no identified genetic origin.     

Maternal cannabis use and birth weight: a meta-analysis

Aims. To estimate the effect of maternal cannabis use on birth weight. Design. published observational studies adjusted for cigarette smoking. Separate analyses were performed for studies of low birth weight and mean birth weight. We used fixed and random effects models, but in all cases the results were identical. Setting. From the Medline database, we identified 10 studies in which the results were adjusted for cigarette smoking. In seven studies, information on cannabis use was collected prenatally. Five studies reported results for differences in mean birth weight associated with maternal cannabis use. Participants. 32 483 women giving birth to live-born infants. Measurements. and odds ratio for low birth weight. Findings. Three analyses of the studies on mean birth weight were conducted to avoid double-counting women from one study. The largest reduction in mean birth weight for any cannabis use during pregnancy was 48 g (95% confidence interval (CI) 83-14 g), with considerable heterogeneity among the five studies. Mean birth weight was increased by 62 g (95% CI 8 g reduction-132 g increase; p heterogeneity 0.59) among infrequent users ( weekly) whereas cannabis use at least four times per week had a 131 g reduction in mean birth weight (95% CI 52-209 g reduction; p heterogeneity 0.25). From the five studies of low birth weight, the pooled odds ratio for any use was 1.09 (95% CI 0.94-1.27, p heterogeneity 0.19). Conclusions. There is inadequate evidence that cannabis, at the amount typically consumed by pregnant women, causes low birth weight. Meta-analysis of Mean birth weight     

Evaluating therapy in cerebral palsy

Summary The optimal design for most clinical trials of treatment is the randomized controlled group trial. This methodology is not, however, uniformly applicable or appropriate. The evaluation of physiotherapy in the management of cerebral palsy in childhood is a good example of treatment for which modification of this trial design is needed. Some of the problems with eight studies in this field published between 1960 and 1993 are reviewed here and an alternative approach proposed. A representative series of single case studies with individual goal setting and a validated outcome measurement, using randomized treatment, would overcome many of the disadvantages of published studies at a greatly reduced cost. The results would enable more effective group trials to be mounted in due course to evaluate the probable impact of providing treatment to a defined population of subjects.