Higher maternal plasma docosahexaenoic acid (DHA) during pregnancy is associated with more mature neonatal sleep-state patterning

Am J Clin Nutr 2002; 76: 608-13

Abstract:
The relationship and effect of docosahexaenoic acid (DHA) on the developing fetal central nervous system (CNS) and sleeping pattern outcomes in infancy have remained unexplored. Researchers conducted a study to investigate whether CNS integrity in newborns (measured by their sleeping patterns) was correlated with maternal concentrations of long-chain polyunsaturated fatty acids (LCPUFAs), in particular DHA. Researchers conclude that sleep patterns of infants born to mothers with higher plasma phospholipid DHA levels reflect a greater CNS maturity.


High levels of n-3 and n-6 LCPUFAs, especially DHA are concentrated in phospholipids located in the brain and eye (retina). During embryonic and neonatal development, an adequate supply of LCPUFAs is essential for the maturation of brain and eye tissue. During this crucial development phase, the fetus is heavily dependent on the mother to supply the majority of LCPUFAs, hence, maternal LCPUFA status is very important.

The effects of LCPUFAs on visual development have been well studied. However, the effects of fetal DHA status on the developing brain have not been investigated due to the lack of appropriate assessment technique for use on the neonate. A link between essential fatty acid intake and sleeping patterns were found in other studies (Fagioli et al 1989, Uauy et al 1996); revealing fatty acid intake regulated sleep-wake cycles. The foundation for this is the infants’ sleep-wake patterns are an expression of central integrative control. Multiple mechanisms in neural and humoral processes in different regions of the brain interact to produce sleep and wakefulness. Studies of the relation between sleep state organization and CNS function showed that changes in sleep architecture are associated with neurologic changes during development and that deviant sleep patterns are associated with neurologic deficits. These researchers tested this hypothesis that the integrity of the CNS in the newborns is related to sleep-wake patterns, by assessing the infants’ prolonged sleep recordings and analyzing its relationship with maternal LCPUFA status, in particular DHA status.

Healthy pregnant women (n=17) were recruited from the Department of Obstetrics and Gynecology at a hospital after they were admitted for delivery and were divided in to 2 categories (1) High DHA (3.0% by wt of total fatty acids; n=10) and (2) Low DHA (≤3.0% by wt of total fatty acids; n=7). At delivery, maternal venous blood was collected to measure maternal PUFA (polyunsaturated fatty acids) status, this result also reflects the infants’ PUFA status. Sleep recordings of infants were obtained by using the Motility Monitoring Sytem (MMS) for the whole duration of the infant’s hospital stay. The basic principle underlying these sleep recordings is that each sleep or wake state involves a unique pattern of motility produced by respiration and body movements. The MMS consists of a sensor pad which is connected to an amplifier leading to a small 24 hour data recorder. The sensor pad is placed under the mattress pad in the infant’s crib. A singular channel of analogue signals from the infant’s respiration and body movements is stored in a data logger and analysed. Simple linear regression analyses were used to describe the relationship between maternal LCPUFA status and infant sleep measures.

This study found that infants in the high DHA group have a more mature pattern of CNS development than infants in the low DHA group. In addition, high DHA infants had less AS (Active sleep) and longer periods of QS (Quiet sleep). The limitations of this study were the correlational analysis with a descriptive and nonrandomized design. These results provide evidence that prenatal exposure to higher levels of DHA leads to a more mature pattern of sleep and wake states. Researchers account the lower amounts of AS and the greater amounts of QS seen in the infants exposed prenatally to higher DHA concentrations to greater CNS maturity compared to infants exposed to lower DHA concentrations. It was also noted high-DHA infants displayed sleep organization soon after birth and was approaching that of normal, older infants. In general, consolidation of sleep increases with age, hence less sleep-wake transition and more wakefulness in the infants in the high-DHA group reflects greater maturity. These results concur with another study (Uauay et al 1996) stating that the functional effects of n-3 supply on sleep wake cycles support the need for dietary n-3 fatty acids during early development.

It was found that the ratio of total n-6 to n-3 fatty acids greatly influenced the integrity of the CNS. Prenatal exposure to a higher ratio of n-6 LCPUFAs to n-3 LCPUFAs resulted in sleep patterns that were opposite to prenatal exposure of lower n-6 LCPUFA to n-3 LCPUFAs and higher DHA concentrations. The higher ratio of n-6 to n-3 fatty acids was correlated with more AS, less QS more sleep wake transition, less wakefulness.

The researchers conclude that differences in the prenatal supply of LCPUFAs, especially DHA, may modify brain phospholipids and affect neural function. Infants born to mothers with a higher level of plasma phospholipid DHA suggest greater CNS maturity. The MMS is a reliable instrument for studying the CNS maturity of infants in relation to their DHA status. To the researcher’s knowledge, this is the first report documenting that maternal DHA status during pregnancy is significantly influenced by dietary DHA and is associated with CNS maturity of the infant at birth.

For more information on this study please find the full article here.

References
1. Uauy R, Peirano P, Hoffman D, Mena P, Birch D, Birch E. Role of essential fatty acids in the function of the developing nervous system. Lipids. 1996 Mar;31 Suppl:S167-76.