Ovine fetal swallowing responses to polyhydramnios

Swallowing of amniotic fluid by late gestation fetuses increases when amniotic fluid volume (AFV) is elevated. Our objectives were to quantitatively characterize fetal swallowing when AFV is elevated above normal to polyhydramniotic levels and to explore the mechanisms that mediate these changes. Late gestation fetal sheep were studied under basal conditions and during intra‐amniotic infusion of lactated Ringer's solution. Control AFV averaged 631 ± 214 mL (SE, n = 6), swallowed volume was 299 ± 94 mL/day, and there were 5.7 ± 1.8 bouts/day of rapid swallowing. During intra‐amniotic infusion, AFV (3065 ± 894 mL) and daily swallowed volume (699 ± 148 mL/day) increased (P