Earlier findings have shown that after unification with the Federal Republic of Germany (FRG) in October 1990 the proportion of very-low-birthweight infants in the former German Democratic Republic (GDR) increased. This study seeks to explore this observation in more detail at the regional level. The analysis of aggregate data of live births in Germany between 1991 and 1997 shows an increasing proportion of very-low-birthweight infants as well as a general trend towards heavier babies in both east and west. The growing proportion of live born infants at very low birthweights in the east, however, seems to be due, in part, to increased registration, most likely reflecting the introduction of the more comprehensive (western) definition of a live birth with unification in October 1990. A fairly distinct east–west pattern in the birthweight distribution present in 1991 had almost disappeared by 1997 and given way to a north–south one.