Maternal supplementation with docosahexaenoic acid does not cause constriction of fetal ductus arteriosus: randomized controlled trial.

Objective: Docosahexaenoic acid (DHA) is recommended routinely in pregnancy to promote fetal development. DHA has anti‐inflammatory activity, but its effects on the fetal heart and circulation are unknown. This study aimed to investigate whether maternal DHA supplementation in the third trimester affects maternal prostaglandin levels and fetal ductus arteriosus flow dynamics. Methods: This was a double‐blind randomized controlled trial with parallel groups conducted between 2018 and 2021. Pregnant women aged over 18 years with a normal fetus at 27–28 weeks' gestation showing no cardiac/extracardiac anomalies or ductal constriction were eligible for the trial. Women consuming substances with a known inhibitory effect on prostaglandin metabolism, such as non‐steroidal anti‐inflammatory drugs and polyphenol‐rich foods, were excluded. The intervention group received oral supplementation of omega‐3 with 450 mg/day of DHA for 8 weeks and the placebo group received capsules of soy lecithin for 8 weeks. Anthropometric measurements, assessment of polyphenol and omega‐3 consumption, fetal morphological ultrasound examination, fetal Doppler echocardiographic examination and blood sample collection were performed at the start of the study and the latter two were repeated at follow‐up. Prostaglandin E2 (PGE2) level and echocardiographic parameters were compared between the intervention and placebo groups and between baseline and follow‐up. Results: A total of 24 participants were included in each group. After 8 weeks, there were no significant differences between the intervention and placebo groups in maternal serum PGE2 level or Doppler echocardiographic parameters of ductal flow. No case of ductus arteriosus constriction was observed. The expected intragroup changes in cardiac morphology, as a result of advancing gestation, were present. Conclusions: Maternal DHA supplementation in the third trimester at a clinically recommended dose did not result in inhibition of PGE2 or constriction of the ductus arteriosus. These findings should be confirmed in postmarket surveillance studies with larger patient numbers in order to test the full safety profile of DHA and provide robust clinical reassurance. © 2024 International Society of Ultrasound in Obstetrics and Gynecology. [ABSTRACT FROM AUTHOR]