EP38.09: Effects of a mindfulness‐based stress reduction intervention during pregnancy for the prevention of severe preterm birth: the IMPACT‐BCN trial

To investigate whether structured intervention based on a Mediterranean diet (MedDiet) or mindfulness-based stress reduction (MBSR) in high-risk pregnancies for small-for-gestational-age (SGA) newborns can reduce the prevalence of preterm birth. In a randomised clinical trial with parallel-group conducted at a University Hospital in Barcelona, Spain (2017-2020), 1221 pregnant women at high-risk for SGA newborns were randomly allocated at 19-23 weeks of gestation into three groups: a MedDiet intervention, a MBSR program or non-intervention. Participants in the MedDiet group (n = 407) received monthly individual and group educational sessions, and free provision of extra-virgin olive oil and walnuts. Women in the MBSR group (n = 407) underwent an 8-week MBSR program adapted for pregnancy. While the main outcome was the prevalence of SGA, one of the secondary outcomes was preterm birth, differentiated as severe (delivery < 32 weeks), moderate (delivery 32-34 weeks), or late (delivery 34-37 weeks). Among 1182 participants included for the intention-to-treat-analysis (n = 392 MedDiet, n = 390 MBSR, n = 400 no intervention), the mean (SD) gestational age at delivery was 39.1 (2.4) weeks in non-intervention group, 39.4 (1.7) in MedDiet group (p = 0.010), and 39.4 (1.6) in the MBSR group (0.018). Preterm birth occurred in 79 women through the trial (6.7%): severe in 13 women (1.1), moderate in 12 (1%) and late in 54 (4.6%). Whereas the prevalence of preterm birth in general was similar among study groups (n = 24, 6.1% for MedDiet, n = 26, 6.7% for MBSR, n = 29, 7.2% for non-intervention, p = 0.082), severe preterm birth was significantly reduced in the MBSR group compared to non-intervention: n = 0 (0%) versus 9 (2.3%), p < 0.001. A structured intervention during pregnancy based on MBSR seem to reduce the prevalence of preterm birth below 32 weeks; however, these results should be considered with caution since the trial was not designed for this specific outcome.