Title

Long chain polyunsaturated fatty acid metabolism in normal pregnancy and pregnancy complicated with gestational diabetes mellitus

Date of Completion

January 1999

Keywords

Health Sciences, Obstetrics and Gynecology|Health Sciences, Nutrition|Biophysics, Medical

Degree

Ph.D.

Abstract

The broad objectives of the current study were to assess maternal polyunsaturated fatty acid (PUFA) status during pregnancy and in pregnancy complicated with gestational diabetes mellitus (GDM). ^ In study 1, 29 healthy pregnant women were followed from early gestation to 8–12 wk postpartum (pp), in a semi-longitudinal design. A dramatic relative decrease in maternal plasma phospholipid arachidonic acid (20:4n6, AA) was evidenced during the third trimester. AA normalized during the early pp period. Maternal PL docosahexaenoic acid (22:60, DHA) wt% also tended to decrease during gestation. In contrast to AA, maternal DHA (wt%) remained low during the pp period. Changes in PL linoleic, acid (18:2n6, LA) and finolenic acid (18:3n3, LNA) were not as marked as observed for their long chain PUFA. ^ In study 2, maternal and fetal PUFA status in pregnancy complicated with GDM was investigated in 15 healthy pregnant women and 15 women with GDM. Maternal plasma and red blood cell (RBC) PL LNA (wt% and μg/ml) was lower and PL DHA (wt% and μg/ml) elevated in women with GDM compared to controls during the third trimester. Fetal RBC PL LA, AA, DHA (wt% and μg/ml) and fetal plasma LNA were significantly lower in GDM compared to controls. Further, RBC PL vein-arterial differences for DHA and Σn3 PUFA (μg/ml), indicating fetal accretion, were lower in GDM compared to controls. Maternal blood HbA 1C and pregravid BNH were negatively associated with fetal RBC PL DHA and AA. Our data point to impairment in placental transfer of LC-PUFA to the fetus in pregnancy complicated with GDM. ^ In study 3, significant positive associations of placental ex vivo biosynthesis of 6-keto-PGF1∝, and PGE2 to fetal plasma AA were demonstrated. Additionally, placental 6-keto-PGF1∝ was positively associated with infant birth weight and head circumference, corrected for gestational age. In women with GDM, placental synthesis of 6-keto-PGF 1∝ was significantly lower relative to controls. We suggest that decreased placental synthesis of PGI2 may alter nutrient transfer to the fetus in pregnancy complicated with GDM. ^