Maternal folic acid supplementation throughout pregnancy

: exploring the effect on children's psychological development

Abstract

Pregnancy is characterised by exponential fetal growth and development. During this period, optimal maternal nutrition is vital to provide the best possible health opportunities for both mother and child (King, 2000). A number of important nutrients have been identified and recommended by NHS (2020) to reduce the risk of adverse pregnancy and birth outcomes. There is clear evidence to support maternal consumption of 400μg/d of folic acid (FA) from preconception to at least 12 gestational weeks (GW), with deficiency during this critical window of development a known risk factor for Neural Tube Defects (NTD) occurrences (MRC, 1991). The link between maternal folate status during pregnancy and children’s other developmental outcomes is less understood. There has been considerable investigation into the physical and cognitive implications for children whose mothers were FA deficient during pregnancy however, the effect on children’s psychological, social, emotional and behavioural development is much less understood. This PhD sought to address this gap. However, rather than focusing on the negative effects of maternal folate deficiency on child developmental outcomes, this PhD applied a positive, resource-focused approach in order to identify the developmental benefits children could experience, psychologically, socially, emotionally and behaviourally in relation to typical (to 12GW) and continued (to at least 36GW) maternal FA use.

A systematic review was conducted to identify and evaluate all relevant literature and assess the quality and risk of bias, an abundance of evidence was uncovered relating to the developmental risks associated with maternal deficiency. Evidence has begun to consider the positive implications for children, particularly in terms of cognition and neurodevelopment, however the duration of use remains largely 10 aligned to the current recommendations. Findings from the review suggest FA dose, time of initiation and duration of use were all important factors requiring further investigation. Secondary data analysis was conducted using the Avon Longitudinal Study of Parents and Children (ALSPAC) to explore the effect of FA supplementation in late pregnancy on children’s cognitive, motor, social, emotional, behavioural and language development using a large, independent study. Findings concurred with those found in the systematic review indicating a potential link between maternal nutrition and later child development. Finally an RCT was used to control FA dose and time of initiation and test the duration of maternal FA use. The developmental impact for children at ~10 years old could then be accurately assessed by comparing children whose mothers stopped supplementing at the recommended 12GW to those who continued to the end of their pregnancy. Key areas of psychological development were measured including their Trait Emotional Intelligence (TEI), Trait Psychological Resilience (TPR), peer attachment style and behaviour strengths and difficulties while testing for mediating effects of peer attachment and parenting style. Results found that continued use caused a significant increase in children’s global TEI and TPR and creativity as measured by the Resiliency Skills and Attitudes Profile (RASP). The mothers of these children were also more likely to adopt a positive parenting style with folate level at 36GW, a significant predictor of TEI, prosocial behaviour and the creativity and values dimensions of TPR. Additionally, mediation analysis identified secure and anxious attachment as significant mediators between folate at 36GW and TEI at 10y.

This thesis recommended further investigation to explore play and children’s language development as potential mechanisms of action. Play opportunities, type 11 and quality are important factors to consider as it fosters cognitive, psychological, social emotional and behavioural development in children. Similarly with language acquisition and interaction, relationships, attachments and emotional bonds can be buffered and nurtured by linguistic skill in the early years having a positive impact on children’s developmental outcome. To conclude, this study indicates that all maternal folic use can provide developmental advantages for children, however continued supplementation promotes optimal development, particularly in the psychological, social, emotional and behavioural domains and recommends mothers continue to supplement for the duration of their pregnancy.

Date of Award	Sept 2023
Original language	English
Supervisor	Marian McLaughlin (Supervisor) & Tony Cassidy (Supervisor)