By Elín Bjarnadóttir
Chariman: Simon Francis Thomsen
Opponent: Malin Barman
Opponent: Helle Hjalgrim
Early life exposure may play a role shaping neurological development and be an important indicator of the child’s subsequent life achievements1–4. During the last trimester of fetal life and the first two years of childhood, the brain undergoes a period of rapid growth where it reaches 80% of its adult weight. Throughout this period, the brain development is particularly vulnerable to the pre- and perinatal environment including not just biological factors like lack of oxygen or extreme prematurity, but also other factors like socio-demographic determinants, stress and nutrition.
The central nervous system is highly enriched with n-3 long chain polyunsaturated fatty acids (n-3 LCPUFA), specifically docosahexaenoic acid (DHA). n-3 LCPUFA is accumulated in the central nervous system during the brain growth spurt from the second half of pregnancy throughout the first two years of life and is dependent on the dietary intake of n-3 LCPUFA. Maternal intake of DHA rich seafood during pregnancy has been associated with improved neurodevelopmental outcome but intervention studies have been ambiguous and inconclusive. Despite this, these findings have caused many women to use fish oil supplement during pregnancy.
The aim of this thesis was to investigate which pre and perinatal factors influence the child’s neurological development in the Copenhagen Prospective Studies on Asthma in Childhood 2010 (COPSAC2010) mother-child cohort with focus on the effect of fish oil supplementation during pregnancy.
In study I we described the overall neurological development of the cohort children. We explore whether early neurological development was affected by maternal age, maternal education, smoking during pregnancy, gestational age, being a first-born, gender, duration of breastfeeding, paternity leave and age at start daycare and. Furthermore, we examined potential effects of persistent wheeze, eczema and number of sick days in the first years of life.
We found that earlier age of milestone achievement was related to male gender, maternal age, gestational age and paternity leave. A higher 1-year language score was associated with female gender and maternal smoking. The 2-year language score was associated by female gender and being first born. Cognitive score at 2 1⁄2 years was found only to be associated with gender, with the 7 girls achieving a higher score than the boys, wheras neurodevelopmental scores were unrelated to breastfeeding, persistent wheeze, eczema, and number of sick days.
In study II we analyzed the effect of n-3 LCPUFA supplementation during 3rd trimester of pregnancy on the child’s neurodevelopmental outcome. The study was double-blinded, randomized placebo controlled trial. The pregnant women received capsules containing 2.4g/day n-3 LCPUFA or matched olive oil capsules from pregnancy week 24 until one week after birth. We found a trend of higher cognitive score in the n-3 LCPUFA group compared to the control group with a significant gender interaction. Gender stratified analysis showed that the boys of the n-3 LCPUFA supplemented mothers scored higher on the cognitive test compared to boys in the control group and achieved motor milestones at a younger age, whereas no differences were seen among the girls.
Conclusion: We have found that gender seems to be the strongest predictor of neurological development during the first years in life. Supplementation with n-3 LCPUFA in 3rd trimester of pregnancy improved cognitive scores and motor development of boys, but did not have any effect on girls. Prescription of dietary fish-oil supplements to pregnant women may therefore optimize neurodevelopment of male offspring.