It has been proposed that prenatal nutrition provides the fetus with a cue allowing it to adjust biological settings in anticipation of postnatal nutrition. To evaluate the reliability of fetal growth rate as a nutritional cue, this study assesses the extent to which a nonnutritional factor‐maternal illness symptoms during pregnancy‐predicts birth outcomes in a large, population‐based sample of Filipino women and their newborns (n = 2,887). Self‐reported illness symptoms were collected during pregnancy and used to predict weight, length, BMI, and gestational age at birth. Independent of potential confounders, number of reported symptoms predicted a significant dose‐response decrease in birth weight and BMI, but not length that reflected a combination of reduced fetal growth rate and reduced duration of gestation. These effects were comparable in male and female offspring, but tended to be stronger when reported closer to term. Among women interviewed at 32 weeks gestation or later, multiple symptoms predicted a 144 g birth weight reduction compared with no symptoms. These findings suggest an acute effect of maternal illness on fetal nutrition late in gestation when growth rate and fat deposition are most rapid. Although modest, the effect was larger than that of most pregnancy macronutrient supplementation trials. These findings using crosssectional, self‐reported illness symptoms highlight a nonnutritional maternal influence on fetal nutrition, which could attenuate its value as a cue of postnatal ecology. Am. J. Hum. Biol., 2008. © 2008 Wiley‐Liss, Inc.