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Birth weight and related variables for offspring of mothers aged 42 or more years
Author(s) -
BARRAI I.,
FRACCARO M.,
LINDSTEN J.,
ZEI GIANNA
Publication year - 1962
Publication title -
annals of human genetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 77
eISSN - 1469-1809
pISSN - 0003-4800
DOI - 10.1111/j.1469-1809.1962.tb01519.x
Subject(s) - parity (physics) , demography , sex ratio , birth weight , population , medicine , offspring , correlation , pregnancy , mathematics , biology , genetics , physics , particle physics , sociology , geometry
Summary Birth weight and related variables are analysed in a sample of 960 babies born in three Swedish Maternity Clinics to mothers aged 42 years on more. The sample is analysed by sex and survival (1 week), and means and standard deviation are calculated accordingly. Correlation and partial correlation and analysis show that the variation in birth weight, which increases with parity, is associated more with succession of births than with parental ages. There is a significant deviation from independence of sex ratio with parity, and the highest contribution to x 2 is given by the first parity. There is found a significant parabolic regression of sex ratio on parity. This indicates that parity per se is more relevant in determining the slight changes in sex ratio than parental ages, of which they are independent. The proportion of non‐survivors is significantly higher than the comparable incidence for the general population of births in Sweden. The birth weight associated with the lowest mortality is higher than the means in both males and females. This has been estimated by the use of the 2 value of Penrose. During the preparation of this paper M. Fraccaro was a guest of the Gruppo di Ricerca 3B del CNEN, at the Institute of Genetics, Pavia. He wishes to thank Prof. L. L. Cavalli Sforza for his kind hospitality.