There has been little work that comprehensively compared the relationship between prenatal care and infant health across multiple countries using similar data sources and analytical models. Such comparative analyses are useful for understanding the background of differences in infant health between populations. We evaluated the association between prenatal care visits and fetal growth measured by birth weight (BW) in grams or low birth weight (,2500 grams; LBW) adjusted for gestational age in eight South American countries using similarly collected data across countries and the same analytical models. OLS and logistic regressions were estimated adjusting for a large set of relevant infant, maternal, and household characteristics and birth year and hospital fixed effects. Birth data were acquired from 140 hospitals that are part of the Latin American Collaborative Study of Congenital Malformations (ECLAMC) network. The analytical sample included 56,014 liveborn infants (,69% of total sample) with complete data born without congenital anomalies in the years 1996–2011 in Brazil, Argentina, Chile, Venezuela, Ecuador, Colombia, Bolivia, and Uruguay. Prenatal care visits were significantly (at p,.05) and positively associated with BW and negatively associated with LBW for all countries. The OLS coefficients ranged from 9 grams per visit in Bolivia to 36 grams in Uruguay. The association with LBW was strongest for Chile (OR = 0.87 per visit) and lowest for Argentina and Venezuela (OR = 0.95). The association decreased in the recent decade compared to earlier years. Our findings suggest that estimates of association between prenatal care and fetal growth are population-specific and may not be generalizable to other populations. Furthermore, as one of the indicators for a country’s healthcare system for maternal and child health, prenatal care is a highly variable indicator between countries in South America.