Of 144 mothers enrolled, 142 blood samples were attained at 21 weeks of gestation. There was no significant difference in baseline characteristics of the mothers in the three supplement groups at enrolment (table ). The course and outcome of pregnancy, e.g. maternal pregnancy weight gain, delivery mode and newborn characteristics were not different between the three supplement groups (table ). One newborn was 35 weeks’ gestational age (DHA-FOS group), and not excluded.
Characteristics of the mothers of the three supplement groups at enrolment, ITT data set (n = 144)
Pregnancy characteristics, outcome and characteristics of the newborns of the three supplement groups (n = 116): one boy was born premature in the DHA-FOS group (35 gestational weeks)
The mean consumption of the supplements over the whole period was not significantly different between the three groups, i.e. 83% (41–100%), 83% (14–98%), and 87% (57–98%) of the prescribed amounts in the Vit/Min, FOS, and DHA-FOS groups, respectively.
There was no significant difference in breast-feeding rates between the three groups. 80% of the infants were exclusively breast-fed up to 3 months in either group.
Blood samples of 115 mothers were available by 37 weeks of pregnancy (80% of 142), 89 blood samples at 3 months after delivery (62%), 78 breast milk samples were obtained of the mothers at 3 months, and because many mothers denied to have blood drawn from their infants, only 50 blood samples could be obtained of their 3-month-old infants (43% of 116 infants) (fig. ). There was no significant difference in the maternal baseline characteristics (tables , ) between those who remained in the study or had blood samples taken and those who did not participate in the follow-up (data not shown).
DHA, ARA and EPA concentrations in the RBC phospholipids of the mothers at enrolment were not different between the three groups (table ). But at 37 weeks of gestation as well as at 3 months after delivery RBC-DHA and RBC-EPA concentrations were significantly higher in the DHA-FOS group than in the two other groups. RBC-ARA concentrations were slightly, but not significantly lower in the DHA-FOS group compared to the others (table ).
ITT data set, summary statistics of fatty acid concentrations in the RBC-membrane phospholipids (RBC-FA%) of mothers and infants and in breast milk lipids (FA%) by supplement group
The DHA content of the breast milk fatty acids 3 months after delivery was twice as high in the DHA-FOS group than in the two other groups, while the ARA contents were not different (table ). The ratio ARA/DHA in the DHA-FOS group compared to the two other groups was therefore significantly reduced from 2.1 ± 0.76 to 1.0 ± 0.43 (p < 0.001). The RBC-DHA concentrations of the infants at 3 months of age in the DHA-FOS group were significantly higher and the ARA concentrations similar to the two other groups (table ).
The RBC-DHA concentrations increased from pregnancy week 21 to week 37 in the DHA-FOS (p < 0.001), FOS (p < 0.01) and Vit/Min (p < 0.01) groups, and then decreased during lactation. The increase was significantly higher in the DHA-FOS group (p < 0.005). After delivery, the DHA values decreased in all groups, but the value 3 months after delivery was slightly higher in the DHA-FOS group than the baseline value, though not significantly so, while the values in the other two groups were lower than at baseline.
The RBC-ARA concentrations in the three groups decreased (but not significantly so) from baseline to 37 weeks of gestation, and increased in either group significantly from the concentration at 37 weeks to 3 months after delivery (p < 0.05). Overall, from baseline to 3 months after delivery, a slight but not significant increase in either group was observed.
The RBC-DHA concentrations of the 3-month-old infants showed a significant correlation with the maternal RBC-DHA concentrations at 3 months after delivery (Pearson's r = 0.55, p < 0.001), explaining 30% of the variance (fig. ). The correlation of the infants’ values with the RBC-DHA concentrations of the mothers at 37 weeks of gestation was also significant (Pearson's r = 0.34, p < 0.05), but not with their RBC-DHA at 21 weeks (Pearson's r = 0.09, n.s.).
RBC-DHA (wt%) of mothers and infants and DHA content in breast milk lipids (wt%) at 3 months after delivery. r = Pearson correlation coefficient.
A significant correlation was found between the breast milk DHA concentration of the mothers and their RBC-DHA concentrations 3 months after delivery (Pearson's r = 0.47, p < 0.0001), explaining 23% of the variance (fig. ). The breast milk DHA concentrations were also significantly correlated with the RBC-DHA concentrations of the mothers at 37 weeks of gestation (r = 0.39, p < 0.001), but not with her RBC-DHA concentrations at gestational week 21 (r = 0.11, n.s.). When the DHA-FOS group and the groups not receiving DHA were analyzed separately, it could be shown that a significant correlation between breast milk DHA and maternal RBC-DHA at 3 months was found only in the groups not receiving DHA (r = 0.402, p < 0.005), and not in the DHA-FOS group (r = 0.18, n.s.).
The correlation between the breast milk DHA and the RBC-DHA concentrations of the infants was only weak (r = 0.30, p = 0.049) (fig. ). The fit for the cubic function between these variables was better, but for the sake of clarity the results are not presented.