Seasonal rythm of births in an rural XIXth century population: Parish of Szczepanowo (Bydgoszcz Voivodeship)

Abstract

Material for this work is taken from the registers of parish Szczepanowo situated approximately in halfway between Gniezno and Bydgoszcz; period covered by registers is from 1830 to 1874. In this time the parish was comprised of 13 villages with average number of about 200 inhabitants each (Roman Catholics, almost exclusively small farm owners and hired farmhands) with population density about 30 persons/km², During the period studied mortality and fertility rates were high ranging respectively from 23 to 45 and from 45-58 per thousand per year. In general main demographic parameters of the population studied are in good agreement with demographic standards for the entire Great Poland region of this time.

Numerical raw data concerning our material are given in table 1. Columns, in order from the left to the right side, contain: 1. months, 2-6. number of live births in specified periods, 7. total number of live births, 8. stillbirths, 9. illegitimate births (A) and 10. births which occured in less than 9 months after wedding (B). The raw data have been corrected for varying number of days in months. With these corrections a clear. statisticaly significant, rythm is found in live briths: maximal num bers of deliveries occured in February and in October, strongly marked minimum during summer months (see fig. 1, fig. 2 — solid line). This is not similar to the distribution of births during year found for parish of Ziemięcice (Silesia) in XIXth c. nor to the rythm of births typical for rural population of modern Poland (fig. 2). Distribution of stillbirths in a year is insignificantly different from that of live births, but sharp, highly statistically significant, discrepancy exists between the distribution. of births resulting from marital and non-marital conceptions (fig. 3, marital ........ line, non-marital —.—.—.— line). This is most probably due to the fact, that non-marital intercourses were considered as „sinful” and their performance demanded specific conditions present in certain months only.

For an explanation of observed rythm a model, based on general knowledge about life conditions in rural areas of XIXth century Poland, has been constructed. In this model there were considered separately influences from factors regulating coitus frequency, fecundability and probability of spontaneous abortions during a year on number of births in each month. The final result is the theoretical distribution of deliveries (fig. 5 — dotted line). Theoretical distribution does not differ significantly from actual one (fig. 5 — solid line) and because in construction of the model mainly cultural (in the broadest sense of the word) factors were accounted for the conclusion of this paper is that seasonal rythm of births is culture- -induced phenomenon and has no connections with any „inborn” sense of time. This claim is supported by the fact, that in the phenomenon we are refering to differences exist among local groups originating from the same territory and breeding population but diverse as to their technology and organization.