Background Fetal programming of adult disease may be a long-term effect of fetal nutrition. Expected short-term effects include changes in body size and proportions at birth. The specific responses of fetal growth to acute undernutrition at varying points in pregnancy are still unclear. Methods We abstracted all birth records of infants born in two midwife training schools in the western Netherlands between 1 October 1944 and 31 March 1946, and compared infants whose mothers were exposed to the Dutch famine of 1944–1945 during specific trimesters of pregnancy with control infants born in 1943. We considered birthweight (BWT), crown-to-heel length (CHL), head circumference (HC), and ratio and regression-adjusted measures of these parameters. Results BWT, CHL, and HC declined with famine exposure late in pregnancy. Changes in WT for CHL paralleled changes in WT alone in size and direction. Results for HC were inconsistent, varying by choice of body size adjustor (WT or CHL), and by method of adjustment (ratio or regression). BWT, CHL, and HC did not change with first trimester famine exposure. Conclusion Even under famine conditions, birth size and body proportions vary only with late pregnancy exposure. HC for body size has the added disadvantage that late pregnancy exposure effects vary drastically with choice of measure. We do not recommend the use of birth size or body proportions as a proxy for fetal nutritional status in the study of adult disease.