Seasonal Changes in Obstetrical Phenomena¹

Abstract

The seasonal variations in disease reflect a) the internal biological rhythm which originally developed to guarantee the preservation of the species (the rhythm is usually related to sunlight or temperature), b) secondary stress phenomena influenced by season (e.g. infections, different working conditions), c) seasonal phenomena caused by customs (festivals, variation in diet etc., based on tradition).The authors have earlier investigated the seasonal variation in the number of births and in cystic glandular hyperplasia, and found a correlation with luminosity but not with temperature ( T i m o n e n et al., 1964).The aim of this study is to examine seasonal phenomena related to pregnancy and childbirth, in the hope that such an examination will help in understanding the reasons for obstetrical complications and perhaps will aid also in planning prophylactic measures. Material and MethodsThe material consists of two series: 27,522 deliveries in Department I1 of Obstetrics and Gynsecology, Helsinki University Central Hospital, from the years 1951-1960 (Series I), and all de-This investigation was aided by a grant from the Sigrid Juselius' Foundation. 32 -Acta Gyn. 44:4.

Preovulatory Overripeness of the Egg in the Human Subject

“…Because of the accessibility of birthdates, we believe that the assessment of birthcurves of patients with all kinds of pathology is a very useful approach to elucidating the etiology and the delineation of congenital malformations and psychopathology. The same holds true for the epidemiology of complications of pregnancy and parturition, since seasonality has been postulated for multiple births (59,68), uterine bleeding (50), spontaneous abortions (43,58), preeclamptic toxemia (9,17,50,67), aplasia of one umbilical artery (51), stillbirth (58, 63) neonatal mortality (30) and other obstetrical phenomena (67). In practically all of these studies the 4-peaked curve is found as predicted by the seasonaloverripeness-hypothesis ( Fig.…”

The Effect of Maternal Age, Parity, Fetal Sex and Season upon Early Intrauterine Development

“…A number of well-documented observations are on record which indicate that characteristic seasonal fluctuations in ovulation (50), conception (8,20,35,63,74,96), abortion (7,21,59) and birth rates (19) and in the incidence of birth defects (4,22,28,45,48,51,58,62,95) exist in virtually all populations investigated. In summarizing the available data, it was demonstrated that in the northern half of Europe ovulation and conception rates showed a major rise in the spring and a minor increase in the fall with declines in the summer and winter.…”

Gynecological Health Screening by Means of Questionnaire and Cytology

“…1959, 1960, 1962) that would cause the increased FSH secretion and thus by increasing the estrogen secretion would raise the protection against infection of the vaginal epithelium. Resistance against a t least puerperal infections ( Timonen et al 1965) has been found to decrease during the winter season. The frequency of this illness is significantly a t its lowest during summer and autumn.…”