Maternal intermittent fasting during pregnancy induces fetal growth restriction and downregulated placental system A amino acid transport in the rat

Research output: Contribution to journalArticlepeer-review

  • External authors:
  • Alaa Alkhalefah
  • Warwick Dunn
  • James W Allwood
  • Kate L Parry
  • Franchesca Houghton
  • Nick Ashton


During Ramadan, many pregnant Muslim women fast between dawn and sunset. Although the impacts of prolonged maternal intermittent fasting (IF) on fetal growth and placental function are under-researched, reported effects include reduced placental weight and birth weight. In this study, pregnant Wistar rats were used to model repeated cycles of IF on fetal development and placental function and to examine sex-specific effects. In the IF group, food was withdrawn daily from 17:00 to 09:00 over 21 days of gestation, while the control group received food ad libitum. Both groups had free water access. IF dams consumed less food, had significantly reduced weight compared to controls, with reduced plasma glucose and amino acids. Both fetal sexes were significantly lighter in the IF group, with reduced fetal plasma amino acids. Placental weights and morphology were unchanged. The profile of placental metabolites was altered in the IF group with sex-specific responses evident. Transplacental flux of 14C-methylaminoisobutyric acid (14C-MeAIB), a system A amino acid transporter substrate, was significantly reduced in both fetal sexes in the IF group. Sodium-dependent 14C-MeAIB uptake into isolated placental plasma membrane vesicles was unchanged. The gene expression of system A transporter Slc38a1, Slc38a2 and Slc38a4 was upregulated in IF male placentas only. No changes were observed in placental SNAT1 and SNAT2 protein expression. Maternal IF results in detrimental impacts on maternal physiology and fetal development, with changes in the placental and fetal metabolite profiles. Reduced placental system A transporter activity may be responsible for fetal growth restriction in both sexes.

Bibliographical metadata

Original languageEnglish
JournalClinical Science
Early online date19 May 2021
Publication statusE-pub ahead of print - 19 May 2021