During gestation the developing fetus is dependent upon nutrient transfer from the mother which is mediated by the placenta. Fetal and placental growth responds to maternal influences such as diet and therefore may be affected adversely by nutrient deprivation. During Ramadan, the month of Islamic fasting, participants must refrain from eating and drinking during daylight hours. Although exempt, many pregnant women in the Middle East participate in the period of fasting. In a human study conducted in Saudi Arabia, we observed that babies which were in utero in the 2nd or 3rd trimester of gestation during the fastsing period had lower mean placental weights and placental weight to birth weight ratios compared to with those not in utero during Ramadan [1]. We have also recorded similar results in rats that were fasted intermittently during pregnancy [2]. The aim of this study was to determine the effect of intermittent fasting on placental calcium transporting protein expression as an indicator of fetal calcium accretion and thus skeletal growth. Pregnant Wistar rats (n=6) were subjected to intermittent fasting (IF); food was withdrawn between 17:00 and 9:00 each day for the duration of gestation. Pregnant control rats (n=6) had free access to food; all rats had unrestricted access to water. Rat placental tissue was collected on embryonic day 21 and calcium transporting protein expression was quantified by Western blotting. Calcium transport across the placenta occurs in 3 stages: diffusion into the trophoblast from maternal plasma through epithelial Ca2+ channels of the transient receptor potential (TRP) gene family, transfer across the trophoblast cytoplasm bound to the calcium binding protein calbindin-D9K and lastly active extrusion into the fetal compartment via the plasma membrane Ca2+-ATPase (PMCA) [3]. We have reported previously a significant decrease in PMCA expression in IF samples compared with control counterparts [4]. Here we show that placental Calbindincalbindin-D9k expression is unchanged in placentas from intermittently fasted rats, where as the epithelial calcium channel TRPv6 is significantly reduced in the IF placental tissue (P<0.01, Mann Whitney U, n=6, Figure 1). These data suggests that fetal calcium accretion may be diminished in the later stages of gestation when the mother is subjected to intermittent fasting. This implies that the increase in fetal weight associated with IF may not be due to greater bone mass.