title: Maternal docosahexaenoic acid (DHA) supplementation and fetal DHA accretion
Creators: name: Montgomery, Colette
Publisher: name: University of Glasgow
Year: 2001
Subjects: subject: Nutrition, Obstetrics

description: Docosahexaenoic acid (DHA) (C22;6n-3) is a polyunsaturated fatty acid that is an essential constituent of cell membranes, particularly of the nervous system where it is found in relatively high concentrations in the brain and retina. In this study expectant mothers were supplied with preformed DHA, at a dosage comparable with current dietary recommendations in a palatable and convenient form, to determine its effects on the nutritional status of both mother and fetus. Hypotheses: This study aimed to test the hypothesis that maternal DHA supplementation enriches maternal DHA status and thereby increases the amount available to the fetus and neonate, as reflected in: (a) maternal red blood cells (RBC) and plasma (b) placental and umbilical cord tissue (c) (fetal) umbilical cord RBC and plasma (d) breast milk. Results: There were no significant differences between groups in baseline samples at 15 weeks. Both groups exhibited an increase in the concentration and % of DHA in maternal RBC and plasma between 15 and 28 weeks, followed by a decrease between 28 weeks and term. However, at 28 weeks, the concentration of DHA was 22% higher in plasma (p=0.02) and 13% higher in RBC (p=0.02) in the fish oil compared to the placebo group. At term, RBC DHA concentration remained 42%) higher (p=0.02) in the fish oil supplemented group. DHA also accounted for a higher % TFA in RBC of fish oil supplemented mothers at 28 weeks (p=0.003) and at term (p=0.01). Total n-3 fatty acids were elevated, with a concomitant lower n-6/n-3 ratio, in the fish oil group at 28 weeks and at birth in both maternal RBC and plasma, for both relative and absolute measurements (all p&lt;0.05). Thus, fish oil supplementation enhanced the overall maternal DHA and n-3 fatty acid status. There were no significant differences between groups in DHA as a % TFA or concentration in cord blood, placental tissue, cord tissue, or breast milk. In both groups, DHA (% TFA and concentration) was higher in cord than maternal RBC and plasma at birth. The relative and absolute amounts of DHA in cord plasma and RBC were most similar to the maximal maternal DHA observed at 28 weeks. The early increase in maternal DHA (between 15 and 28 weeks) was greater in the fish oil group; the subsequent decline in maternal status following mid-gestation (between 28 weeks and term) was less in the fish oil group. The matemo-fetal difference was also less marked in the fish oil group. Fish oil supplementation thus enhanced maternal ability to provide the fetus with DHA during the second trimester, and limited the third trimester depletion of maternal stores and status, ensuring a more favourable maternal status by term such that the matemo-fetal gradient was less severe. Conclusions: Maternal DHA status is maximal in mid-trimester and declines to term. The extent of this decline is limited in supplemented compared to unsupplemented mothers. The relationship between mid-trimester maternal and term cord blood DHA suggests that timing of maternal supplementation is important, and is most likely to be beneficial if it begins before mid-gestation. Maternal DHA supplementation enhances maternal DHA status and may aid preferential transfer of DHA from mother to fetus. Maintenance of a higher DHA status at term may also enhance maternal DHA status in subsequent pregnancies. (Abstract shortened by ProQuest.).