To the Editor:—In the September issue of your journal there is an article about causes of prematurity (Anderson, N. A., and Lyon, R. A.: Causes of Prematurity A Review of the Literature, Am. J. Dis. Child. 58:586 [Sept.] 1939). In 1928 I wrote a thesis on premature children (Keizer, D. P. R.: De couveusebehandeling van praemature kinderen in de Amsterdamsche vrouwenkliniek over de jaren 1921-1926, Amsterdam, P. H. Vermeulen, De Academische Boekwinkel, 1928) in which I gave statistical data on 858 premature births.
As the cause of prematurity I found:
The mothers in 34.5 per cent of the 858 cases were primiparas; in 25.4 per cent, secundiparas; in 20.8 per cent, tertiparas or quadriparas, and in 19.5 per cent, quintiparas or n-paras. In this series the birth weight for prematurity was fixed at under 2,500 Gm. (5 Dutch pounds).