Open AccessSeasonal Birth Pattern in Sweden in Relation to Birth Order and Maternal Age
Author(s) -
Sandahl Björn
Publication year - 1978
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.3109/00016347809156517
Subject(s) - parity (physics) , medicine , gestational age , demography , seasonality , birth order , age groups , obstetrics , pregnancy , statistics , mathematics , population , biology , physics , environmental health , particle physics , sociology , genetics
. The influence of both maternal age and parity on seasonal birth patterns in Sweden was studied, using the Swedish Medical Birth Register for 1973. The register contained reports of 109342 pregnancies. A test for seasonality, using a squared sinus function and an analysis of variance, was performed for each age and parity group. Significant differences were shown for parity irrespective of age and age groups within parity groups. There was one exception: no influence of parity could be demonstrated in women more than 35 years of age. For the lowest and the highest age groups (all parities), there was no significant seasonality in birth rate tested by the squared sinus method. This was also true for parity 3 (age group 20–24) and parity 1 (age group 30–34). The other age groups and parity classes show a significant seasonality with a maximum of births in April and May.