Fertility and Reproduction in a Swedish Population Group without Family Limitation.

The present article reviews a previous investigation relating to a small Swedish isolate in Estonia. A brief description is given of ways of obtaining data on fertility and sterility, etc., from parish registrations. The period observed is 1840-1900 when no family limitation seems to have existed. The frequency of sterility is studied, by observing the time when the last child of the marriage was born. A decrement table is derived from the frequencies of last births, and from this the mean expectation of the fertile period may be calculated. Duration of marriage at the last birth is used for calculating fecundity rates by modifying a method previously given by S. G. W. Wahlund. Intervals between successive births are discussed. Some specific observations are made concerning possible causes of variation, and the effect of pen-natal mortality on fertility is demonstrated. Finally, methods for calculating legitimate fertility rates by order of birth are classified. These are closely related to techniques developed in later years for studying the populations of entire countries. [ABSTRACT FROM AUTHOR]