- A study led by researcher Jorge López-Tello (IIBM) offers biological clues as to how maternal emotional well-being may influence the baby’s development
- Placentas from women who took part in a mindfulness-based stress reduction programme had a different fatty acid profile and changes in genes involved in hormone production
A team of researchers from the Institute for Biomedical Research Sols-Morreale (IIBM), CSIC-UAM, has found that taking part in a mindfulness programme during pregnancy is associated with changes in the lipid composition and endocrine function of the placenta. They worked with BCNatal (Hospital Clínic and Hospital Sant Joan de Déu, Barcelona), the Universidad Complutense de Madrid and the University of Cambridge. The study, led by Jorge López-Tello, has been published in the journal Placenta.
Maternal mental health, a growing challenge
According to the World Health Organization, anxiety is one of the most common mental health disorders worldwide. Pregnancy is a particularly vulnerable period: an estimated 5–20% of pregnant women experience stress, anxiety or depression.
The impact goes beyond the mother. Psychological distress during pregnancy has been linked to a higher risk of obstetric complications, such as preeclampsia or impaired fetal growth. It has also been associated with effects that can extend into childhood, including emotional, behavioural or learning difficulties.
“We know that a mother’s emotional well-being affects pregnancy, but we still understand very little about the biological mechanisms that link it to the baby’s development. Understanding how the placenta responds is key to finding out,” explains López-Tello.
What changes in the placenta
The study analysed placentas from women who took part in the IMPACT BCN clinical trial, one of the leading maternal-fetal health studies in Spain. Some participants followed a mindfulness-based stress reduction programme adapted for pregnancy, which included meditation, prenatal yoga and exercises focused on bonding with the baby. The rest received standard prenatal care.
Placentas from the mindfulness group showed changes in several fatty acids that are essential for fetal development. They also showed lower expression of genes involved in producing placental hormones, such as placental lactogen, and of key enzymes needed to make steroid hormones such as progesterone and oestrogens.
Some of these changes depended on the baby’s sex and were more evident in placentas from male fetuses. This matches previous work by the group suggesting that the male placenta responds more sensitively to changes in the maternal environment.
“Our data suggest that the mother’s psychological state may leave a mark on how the placenta works, at both the metabolic and the hormonal level. It is a first step towards understanding why looking after mental health during pregnancy may bring benefits that go beyond the mother herself,” says the researcher.
Another piece of the puzzle
Previous studies from the IMPACT BCN trial had shown that this intervention reduced maternal anxiety and the proportion of babies born small for their gestational age. It had also been associated with more favourable markers of early neurodevelopment. The new study points to the placenta as one possible link between maternal emotional well-being and these outcomes.
“These interventions are accessible, non-pharmacological and well accepted by pregnant women. Gaining a better understanding of what happens at the biological level will help us assess their potential role in prenatal care,” adds López-Tello.
The authors note that this is an association study with a limited number of samples. Further research will be needed to confirm these results and to find out whether the changes in the placenta have long-term consequences for the baby’s health.
Reference: Lopez-Tello et al. (2026). Mindfulness-based stress reduction during pregnancy is associated with changes in placental fatty acid metabolism and endocrine function. Placenta. DOI: 10.1016/j.placenta.2026.10.004