Gestational age dependent content, composition and intrauterine accretion rates of fatty acids in fetal white adipose tissue

Abstract

Background Little is known about the gestational age (GA) dependent content, composition and intrauterine accretion rates of fatty acids (FA) in fetal white adipose tissue (WAT). Objective & design To acquire this information, we collected abdominal subcutaneous WAT samples from 40 preterm and term fetuses. Their GA ranged from 22 to 43 weeks. FA were expressed as mg/g wet WAT and g/100 g FA (g%). Intrauterine WAT FA accretion rates were estimated for appropriate (AGA) and large (LGA) for gestational age infants. Results From 25 to 40 weeks gestation, saturated-FA (SAFA) increased from 83 to 298 mg/g WAT and monounsaturated-FA (MUFA) from 83 to 226 mg/g WAT, while polyunsaturated-FA (PUFA) increased insignificantly from 18.0 to 23.2 mg/g WAT. As percentages of total FA, SAFA increased from 46 to 55 g%, MUFA decreased from 44 to 41 g%, and PUFA from 10.3 to 4.26 g%. Docosahexaenoic (DHA) and arachidonic acid (AA) accretion rates in WAT during the 3rd trimester for AGA infants were 88 and 193 mg/week, respectively. Contemporaneous DHA and AA accretion rates for 4500 g LGA infants were 184 and 402 mg/week, respectively. Compared to the whole 3rd trimester, increment rates during the last 5 weeks of gestation were about 2-fold higher. Conclusion FA accretion rates, notably those of DHA and AA, may be important for designing nutritional regiments for preterm infants. The current WAT-DHA and WAT-AA accretion rates are considerably lower than previously reported in the literature.