Aspects of fetal learning and memory.

Ninety-three pregnant women were recruited to assess fetal learning and memory, based on habituation to repeated vibroacoustic stimulation of fetuses of 30-38 weeks gestational age (GA). Each habituation test was repeated 10 min later to estimate the fetal short-term memory. For Groups 30-36, both measurements were replicated in a second session at 38 weeks GA for the assessment of fetal long-term memory. Within the time frame considered, fetal learning appeared GA independent. Furthermore, fetuses were observed to have a short-term (10-min) memory from at least 30 weeks GA onward, which also appeared independent of fetal age. In addition, results indicated that 34-week-old fetuses are able to store information and retrieve it 4 weeks later.

Associations between term birth dimensions and prenatal exposure to essential and trans fatty acids.

BACKGROUND: Certain essential long-chain polyunsaturated fatty acids (LCPUFAs) are considered important for fetal growth and brain development, whereas industrial trans fatty acids (mainly 18:1trans) have been associated with negative effects. The aim of this study was to investigate associations between term birth dimensions and prenatal exposure to some of these fatty acids, reflected by neonatal fatty acid concentrations at birth. METHODS: Data of up to 700 infant-mother pairs from the Maastricht Essential Fatty Acid Birth Cohort were used for the present study. Unadjusted and multivariable-adjusted linear regression analyses were performed to investigate associations between birth weight, birth length or head circumference and relative concentrations of docosahexaenoic acid (DHA), arachidonic acid (AA), dihomo-gamma-linolenic acid (DGLA) and trans-octadecenoic acids (18:1t) measured in phospholipids of the walls of umbilical arteries and veins, and in umbilical cord plasma and erythrocytes. RESULTS: After optimal adjustment, a significant negative association was observed between birth weight and umbilical plasma DHA concentrations. Negative associations were also found for AA concentrations measured in umbilical plasma and in arterial and venous vessel walls. Birth length was negatively related to arterial vessel wall AA concentrations only. A significant negative association was observed for the relationship between 18:1t in cord erythrocytes and birth weight. For DGLA no significant associations were observed. CONCLUSIONS: Results seem to preclude a role of DHA and AA as growth factors per se. Their negative relationships with birth dimensions may result from a limited maternal-fetal LCPUFA transfer capacity. Potential effects of 18:1t and DGLA on birth dimensions are probably small or non-existing.

Prenatal arachidonic acid exposure and selected immune-related variables in childhood.

Arachidonic acid (AA) is considered essential in fetal development and some of its metabolites are thought to be important mediators of the immune responses. Therefore, we studied whether prenatal exposure to AA is associated with some immune-related clinical conditions and plasma markers in childhood. In 280 children aged 7 years, atopy, lung function and plasma inflammation markers were measured and their relationships with early AA exposure were studied by linear and logistic regression analyses. AA exposure was deduced from AA concentrations in plasma phospholipids of the mothers collected at several time points during pregnancy and at delivery, and in umbilical cord plasma and arterial and venous wall phospholipids. In unadjusted regression analyses, significant positive associations were observed between maternal AA concentrations at 16 and 32 weeks of pregnancy (proxies for fetal AA exposure) and peak expiratory flow decline after maximal physical exercise and plasma fibrinogen concentrations of their children, respectively. However, after correction for relevant covariables, only trends remained. A significant negative relationship was observed between AA concentrations in cord plasma (reflecting prenatal AA exposure) and the average daily amplitude of peak expiratory flow at rest, which lost significance after appropriate adjustment. Because of these few, weak and inconsistent relationships, a major impact of early-life exposure to AA on atopy, lung function and selected plasma inflammation markers of children at 7 years of age seems unlikely.

Associations between neonatal birth dimensions and maternal essential and trans fatty acid contents during pregnancy and at delivery.

Since birth dimensions have prognostic potential for later development and health, possible associations between neonatal birth dimensions and selected maternal plasma fatty acid contents were investigated, using data from 782 mother-infant pairs of the Maastricht Essential Fatty Acid Birth cohort. Unadjusted and multivariable-adjusted regression analyses were applied to study the associations between birth weight, birth length or head circumference and the relative contents of DHA, arachidonic acid (AA), dihomo-gamma-linolenic acid (DGLA) and 18 : 1trans (18 : 1t) in maternal plasma phospholipids sampled during early, middle and late pregnancies, and at delivery. Where appropriate, corrections were made for relevant covariables. Significant 'positive' associations were observed between maternal DHA contents (especially early in pregnancy) and birth weight (B = 52.10 g, 95 % CI 20.40, 83.80) and head circumference (B = 0.223 cm, 95 % CI 0.074, 0.372). AA contents at late pregnancy were 'negatively' associated with birth weight (B = - 44.25 g, 95 % CI - 68.33, - 20.16) and birth length (B = - 0.200 cm, 95 % CI - 0.335, - 0.065). Significant 'negative' associations were also observed for AA contents at delivery and birth weight (B = - 27.08 g, 95 % CI - 47.11, - 7.056) and birth length (B = - 0.207 cm, 95 % CI - 0.330, - 0.084). Maternal DGLA contents at delivery were also significantly 'negatively' associated with neonatal birth weight (B = - 85.76 g, 95 % CI - 130.9, - 40.61) and birth length (B = - 0.413 cm, 95 % CI - 0.680, - 0.146). No significant associations were observed for maternal 18 : 1t contents. We conclude that during early pregnancy, maternal DHA content may programme fetal growth in a positive way. Maternal AA and DGLA in late pregnancy might be involved in fetal growth limitation.

Dietary arachidonic acid dose-dependently increases the arachidonic acid concentration in human milk.

Lactation hampers normalization of the maternal arachidonic acid (AA) status, which is reduced after pregnancy and can further decline by the presently recommended increased consumption of (n-3) long-chain PUFA [(n-3) LCPUFA]. This may be unfavorable for breast-fed infants, because they also require an optimum supply of (n-6) LCPUFA. We therefore investigated the LCPUFA responses in nursing mothers upon increased consumption of AA and (n-3) LCPUFA. In a parallel, double-blind, controlled trial, lactating women received for 8 wk no extra LCPUFA (control group, n = 8), 200 (low AA group, n = 9), or 400 (high AA group, n = 8) mg/d AA in combination with (n-3) LCPUFA [320 mg/d docosahexaenoic acid (DHA), 80 mg/d eicosapentaenoic acid, and 80 mg/d other (n-3) fatty acids], or this dose of (n-3) LCPUFA alone [DHA + eicosapentaenoic acid group, n = 8]. Relative concentrations of AA, DHA, and sums of (n-6) and (n-3) LCPUFA were measured in milk total lipids (TL) and erythrocyte phospholipids (PL) after 2 and 8 wk and changes were compared by ANCOVA. The combined consumption of AA and (n-3) LCPUFA caused dose-dependent elevations of AA and total (n-6) LCPUFA concentrations in milk TL and did not significantly affect the DHA and total (n-3) LCPUFA increases caused by (n-3) LCPUFA supplementation only. This latter treatment did not significantly affect breast milk AA and total (n-6) LCPUFA concentrations. AA and DHA concentrations in milk TL and their changes were strongly and positively correlated with their corresponding values in erythrocyte PL (r(2) = 0.27-0.50; P