Polyunsaturated Fatty Acid Levels in Maternal Erythrocytes of Japanese Women during Pregnancy and after Childbirth.

Background: The transport of polyunsaturated fatty acids (PUFAs), such as arachidonic acid (ARA, 20:4n-6) and docosahexaenoic acid (DHA, 22:6n-3), to the fetus from maternal stores increases depending on the fetal requirements for PUFA during the last trimester of pregnancy. Therefore, maternal blood PUFA changes physiologically with gestational age. However, the changes in PUFA levels in maternal blood erythrocytes during pregnancy and after childbirth have not been fully investigated in a fish-eating population.

Objective: To examine the changes of ARA and DHA levels in maternal erythrocytes with the progress of pregnancy and the relationship between maternal and umbilical cord erythrocyte PUFA levels in pregnant Japanese women who habitually eat fish and shellfish.

Design: This study was performed as a part of the adjunct study of the Japan Environment and Children's Study (JECS). The participants were 74 pregnant women. The maternal blood samples were collected at 27, 30, and 36 weeks of pregnancy, and 2 days and 1 month after delivery, and umbilical cord blood was collected at delivery. The fatty acid levels of erythrocytes in these blood samples were determined.

Results: ARA and DHA levels in maternal erythrocytes tended to decrease with the progress of pregnancy. While the DHA level decreased further after delivery, the ARA level returned to the value at 27 weeks of pregnancy within 1 month after delivery. The n-3 and n-6 PUFA levels in maternal erythrocytes at 27, 30, and 36 weeks of pregnancy were significantly positively correlated with the corresponding fatty acid levels in umbilical cord erythrocytes.

Conclusion: The present findings showed a significant change in erythrocyte PUFA levels during pregnancy and after childbirth in a fish-eating population. The PUFA levels of maternal blood after the second trimester may be a reliable marker for predicting PUFA levels in infants' circulating blood.