An Investigation of the Relationship Between the Chronotypes of Mothers Who Had Normal Delivery and Various Characteristics of Them and Their Babies

Introduction: Biological changes in human metabolism due to daylight and heat are expressed as circadian rhythm, and its classification according to individuals and their genetic differences is called chronotype. In recent years, there has been an increase in studies examining the relationship between circadian rhythm and birth. Purpose: This study’s first aim was to investigate the relationship between the chronotypes of mothers and time of birth, season, meridians in which they were born, and the gender of their babies. Its second aim was to examine the relationship between the birth times and chronotypes of pregnant women and the time of their deliveries. 
Method: The study was conducted among women presented to Alanya Training and Research Hospital Gynecology and Obstetrics Polyclinic between 01.02.2022 and 31.03.2022. The study included 147 women remembering the date and time of delivery. Participants were selected among the mothers who gave a normal birth, did not have labor induction, whose birth started with spontaneous contractions, and had a healthy pregnancy. A questionnaire form including sociodemographic characteristics, obstetric information, and Horne and Östberg's Morningness- Eveningness scale were applied face to face. One-way ANOVA, Chi-Square, and logistic regression analyses were employed to analyze the data. 
Results: The chronotypes of the participants revealed that 45 women (30.6%) were morning type, 90 women were intermediate type (61.2%), and 12 women were evening type (8.2%). No difference was found between the chronotype scores of the mothers and the birth hours of their babies (p = .324). There was no difference between mothers' chronotype scores and birth meridians (p = .842). In addition, no significant relationship was found between the mothers' own birth hours and the birth hours of their babies (p= .050). 
Conclusion: There was no relationship between birth time, season, gender, birth meridian, and chronotype. The limitation of the study may be related to the recall bias, the effect of confounding factors, and the sample size. However, we think it is an interesting field in terms of providing a different perspective on the differences in performance and mood of people with further studies regarding chronotype.