Background During pregnancy, consuming alcohol and using illicit drugs can have serious health implications for both mother and child. Behavioral change interventions, especially those underpinned by theoretical constructs, can be effective in reducing harmful substance use among pregnant women. Purpose To understand what type of behavior change mechanisms could be useful in reducing alcohol consumption or achieving abstinence from illicit drug use during pregnancy, this review aimed to identify behavior change techniques (BCTs), the smallest, active components of interventions that may be effective. It also aimed to establish the extent that psychosocial-based theories were used to inform intervention design. Methods To identify eligible randomized controlled trials (RCTs), five databases were searched electronically from the end search dates of the most recent Cochrane systematic reviews on behavioral interventions for each behavior, until March 2018. Within the RCTs, intervention descriptions were analyzed for BCT content and extent of theory use in the intervention design process and outcome measurements, in each trial, was established. "Effectiveness percentages," the number of times a BCT had been a component of an effective intervention divided by the total number of interventions it had been used in, were calculated for BCTs used in two or more trials. Results Including all RCTs from the Cochrane reviews, and those published subsequently, nine alcohol and six illicit drug trials were identified. Interventions tested in four alcohol RCTs and no illicit drugs RCTs showed positive results. Subsequent data were extracted for alcohol consumption trials only. Thirteen BCTs showed "potential effectiveness" for alcohol consumption. Six of nine included alcohol trials reported using theory but not extensively. Conclusions Action planning, behavioral contract, prompts/cues, self-talk, offer/direct toward written material, problem solving, feedback on behavior, social support (unspecified), information about health consequences, behavior substitution, assess current readiness and ability to reduce excess alcohol consumption, goal setting (behavior), and tailor interactions appropriately are BCTs that could be useful in helping reduce alcohol consumption among pregnant women.
