Change search
ReferencesLink to record
Permanent link

Direct link
The association between dystocic labors and circadian signals
Umeå University, Faculty of Medicine, Department of Clinical Sciences, Obstetrics and Gynaecology.
Show others and affiliations
2013 (English)In: American Journal of Obstetrics and Gynecology, ISSN 0002-9378, E-ISSN 1097-6868, Vol. 208, no 1, S139-S140 p.Article in journal, Meeting abstract (Other academic) Published
Abstract [en]

Objective: Human deliveries commonly occur during the dark period of the day. Melatonin hormone is released as a circadian signal from the human brain, and has been shown to have a synergistic effect together with oxytocin in facilitating the uterine contractions during labor. Melatonin is inhibited by light and energized by dark. During winter the numbers of light hours per day in Sweden are few, but during the summer they are numerous. In Tanzania there is no season difference.

Study Design: In 2011,452 Tanzanian and 919 Swedish healthy primiparas with a normal pregnancy and a spontaneous onset of labor were included in the study. Time and date together with the length and outcome of delivery were studied, and a statistical comparison was made.

Results: 47% of the Swedish deliveries started in early morning, and 48% ended at midnight. The median time of active labor was significantly longer during the summer season (May to August vs. November to February, p=0.05). The frequency of labor dystocia was increased during summer season, and significantly more in the region on Sweden with midnight sun (29 vs. 40%, p=0.03).

48% of Tanzania labors started at midnight, and 41% ended at lunch time. Among Tanzanian women, no difference in median time of active delivery (p=0.5) or the frequency of dystocic labors was shown, according to season of the year (13.7 vs. 14.1 %, p=0.8).

Oxytocin was used in 68% of the Swedish deliveries, and the use was higher during the summer season. Oxytocin was used in 31% of the Tanzanian deliveries. No difference in use of oxytocin was shown according to season.

Conclusion: In this project a variation of labor dystocia according to season of the year has been studied. A significant overrepresentation of prolonged and dystocic deliveries were shown during the summer season in Sweden. This new knowledge may be of a great importance, when handling a dysfunctional labor.

Place, publisher, year, edition, pages
Elsevier, 2013. Vol. 208, no 1, S139-S140 p.
National Category
Obstetrics, Gynecology and Reproductive Medicine
URN: urn:nbn:se:umu:diva-66411ISI: 000313393500310OAI: diva2:607420
33rd Annual Meeting/Pregnancy Meeting of the Society-for-Maternal-Fetal-Medicine (SMFM), FEB 11-16, 2013, San Francisco, CA
Available from: 2013-02-22 Created: 2013-02-19 Last updated: 2013-02-22Bibliographically approved

Open Access in DiVA

No full text

Search in DiVA

By author/editor
Wihlbäck, Anna-carin
By organisation
Obstetrics and Gynaecology
In the same journal
American Journal of Obstetrics and Gynecology
Obstetrics, Gynecology and Reproductive Medicine

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Total: 95 hits
ReferencesLink to record
Permanent link

Direct link