Is there seasonality in human ovulation?
To study seasonality in human ovulation in a direct way, we measured the occurrence of ovulation in infertile patients with spontaneous menstrual cycles (< 6 weeks) who visited the fertility clinic at the University Hospital Nijmegen in the Netherlands for the first time in 1991 or 1992 (n = 407). Ovulation was detected using serial transvaginal ultrasound and midluteal progesterone measurement and was performed during one screening cycle. The frequency of ovulatory cycles per month varied from 73% to 93% (not statistically significant). No seasonal pattern in ovulation was found in subfecund Dutch women with spontaneous menstrual cycles. This finding was not confounded by the effects of age of the women, body mass index, or disorders that could influence ovulation.
Stolwijk
A M
AM
Department of Medical Informatics, Epidemiology, and Statistics, University of Nijmegen, The Netherlands.
Aarts
F J
FJ
Hamilton
C J
CJ
Jongbloet
P H
PH
Zielhuis
G A
GA
D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D007246:Infertility / Q000453:epidemiology; D016015:Logistic Models; D009426:Netherlands / Q000453:epidemiology; D016017:Odds Ratio; D010060:Ovulation / Q000502:physiology*; D012189:Retrospective Studies; D012621:Seasons