GESTATIONAL-AGE DEPENDENCY OF ESSENTIAL FATTY-ACIDS IN CORD PLASMA-CHOLESTEROL ESTERS AND TRIGLYCERIDES

Plasma cholesterol ester and triglyceride fatty acid compositions of 3 8 singleton deliveries (23-42 wk), three twins (32, 39, and 40 wk), an d their mothers were investigated. No gestational age-dependent change s occurred in maternal fatty acid compositions. Long-chain polyunsatur ated fatty acids in fetal cholesterol esters and triglycerides were hi gher, and their precursors (18:2c,omega 6 and 18:3c,omega 3) were lowe r than those in corresponding maternal lipid classes. Except for 22:6c ,omega 3, 20:2c,omega 6, and 22:5c,omega 6, all long-chain polyunsatur ated fatty acids in fetal triglycerides increased with advancing gesta tion. Fetal triglyceride 22:6c,omega 3/22:5c,omega 3 ratio decreased, whereas 22:5c,omega 6/22:4c,omega 6 remained constant. Fetal cholester ol ester and triglyceride 20:3c,omega 9 contents were higher than thos e of corresponding maternal fractions and did not change with gestatio n. Triglyceride 18:2c,omega 6 contents of babies with gestational ages of more than 34 wk were linearly related to those of their mothers. T he data suggest that increasing triglyceride long-chain polyunsaturate d fatty acid content with advancing gestation is partially caused by D elta 6- and Delta 5-desaturase maturation in the liver. Constancy of 2 2:6c,omega 3 and 22:5c,omega 6/22:4c,omega 6 and decrease of 22:6c,ome ga 3/22:5c,omega 3 in triglycerides may point to low hepatic Delta 4-d esaturation. Transplacental transport of 20:3c,omega 9, followed by fe tal conservation, should be considered. High 18:2c,omega 6 and low 18: 3c,omega 3 intakes by the mother may unfavorably influence fetal produ ction of 22:6c,omega 3 in the liver. Because of low hepatic Delta 4-de saturation capacity the influence may be small, however.