Assessment of the Health in Pregnancy Grant policy in Scotland: a natural experiment

Abstract Background Interventions during pregnancy and the early years aim to improve infant and child outcomes. In the UK, the Health in Pregnancy (HiP) Grant was introduced in April, 2009, and withdrawn in April, 2011. It was a universal unconditional cash transfer of £190 designed to provide additional financial support in the third trimester. This cash transfer was an incentive for expectant mothers to seek timely health advice from a professional. The present study aimed to assess the effectiveness of the HiP Grant in Scotland: did mothers who received HiP have babies with a different birthweight and have different health behaviours compared with mothers who did not receive HiP? Methods The HiP Grant was assessed as a natural experiment to compare outcomes before its introduction (preintervention) and immediately after its withdrawal (postintervention) with those during the intervention period. Routinely collected data on all singleton births in Scotland between Jan 1, 2004, and Dec 31, 2013, at 26–44 weeks' gestation were used. The outcomes we report on are birthweight, contacting a midwife before 25 weeks of pregnancy, and smoking during pregnancy. Interrupted time-series models were fitted to the individual data, allowing for varying time trends and adjusting for maternal and birth characteristics. A-priori subgroup analyses were conducted for groups most likely to benefit from the intervention including nulliparous women and women from the most deprived areas. Findings 272 935 babies were born in the preintervention period, 109 775 in the intervention period, and 144 663 in the postintervention period. Compared with the preintervention period, birthweight remained unchanged in the intervention period (–2·9 g, 95% CI −7·1 to 1·4) and decreased slightly post intervention (–7·9, −14·0 to −1·8). During the intervention period, more women booked before 25 weeks' (odds ratio 1·17, 95% CI 1·10 to 1·24) whereas smoking was unchanged (0·99, 0·96 to 1·02). Results for subgroup analyses showed broadly similar results. Interpretation The size of the payment and the null effect on birthweight might indicate that birthweight was an ambitious primary outcome. The positive effects on early booking demonstrate that a cash incentive might help to modify behaviour. These results can inform other policies aiming to change behaviour. Funding This project was funded by the National Institute for Health Research (NIHR) Public Health Research Board (PHRB) (project number 12/3070/02). RD, SO, and AL are funded by the Medical Research Council (_UU_12017/5) and the Chief Scientist Office of the Scottish Government Health Directorates (SPHSU2).