A balance of omega-3 and omega-6 polyunsaturated fatty acids is important in pregnancy

Emerging evidence suggests that omega (n)-3 PUFA and their metabolites improve maternal and neonatal health outcomes by modifying gestation length, and reducing the recurrence of pre-term delivery. N-3 PUFA has been associated with prolonged gestation and increased birth dimensions such as birth weight and head circumference. However, mothers giving birth to larger babies are at an increased risk of having dysfunctional labour, genital tract laceration, and delivery via caesarean section. Likewise, high infant weight at birth has been linked to several metabolic and cardiovascular disorders in the offspring. Prolonged gestation also leads to reduced placental function which has been implicated in fetal distress, and perinatal death. Till date, the mechanism through which high n-3 PUFA intake during pregnancy increases gestation length and birth weight is vaguely understood. Early and later stages of pregnancy is characterised by increased production of pro-inflammatory cytokines which are required for pregnancy establishment and labour regulation respectively. Conversely, mid-stage of pregnancy requires anti-inflammatory cytokines necessary for uterine quiescence, pregnancy maintenance and optimal fetal growth. Apparently, changes in the profiles of local cytokines in the uterus during different stages of pregnancy have a profound effect on pregnancy progression. This review focuses on the intake of n-3 and n-6 PUFA during pregnancy and the impact it has on gestation length and infant weight at birth, with a particular emphasis on the expression of inflammatory cytokines required for timely pregnancy establishment (embryo reception and implantation) and labour induction. It is concluded that an appropriate dose of n-3 and n-6 PUFA needs to be established during different stages of pregnancy.