The association of lowered alcohol prices with birth outcomes and abortions: a population-based natural experiment
Background and aims: Alcohol use during pregnancy remains an important risk factor for adverse birth outcomes, but little is known regarding how alcohol prices affect pregnancy outcomes on the population level. We assess the associations between decreased alcohol prices with birth outcomes and abortions.
Design: Using national registers, we used interrupted time-series modelling to compare outcomes of pregnancies conceived before and after a tax cut, resulting in 33% mean decrease of off-premise alcohol prices on 1 March 2004. We also addressed possible heterogeneity of the associations by maternal age and household income.
Participants: All registered pregnancies starting 2 years before and 1 year after the alcohol price cut (analysis sample consisted of 169 735 live births and 32 441 abortions).
Measurements: The outcomes were birth weight, gestational age, the probability of low birth weight (< 2500 g at birth), preterm birth (< 37 weeks of gestation), any congenital malformations and share of registered abortions of pregnancies.
Findings: On the population level, lowered alcohol prices were associated with an increase in abortions immediately after the price cut [+0.84 percentage points; 95% confidence interval (CI) = 0.2, 1.4]. For birth outcomes, negative associations were observed among women in the lowest income quintile; for example, increased probabilities of low birth weight (+1.5 percentage points; 95% CI = 0.4, 2.6) and preterm birth (+1.98 percentage points; 95% CI = 0.8, 3.2). All changes were strongest immediately after the price cut and attenuated during the course of the following year.
Conclusions: Lowered alcohol prices in Finland were associated with a short-term increase in adverse birth outcomes among low-income mothers and an overall increase in abortions.