Maternal plasma levels of oxytocin during physiological childbirth - a systematic review with implications for uterine contractions and central actions of oxytocin.

Autor: Uvnäs-Moberg K; University of Agriculture (SLU), Uppsala, Sweden., Ekström-Bergström A; School of Health and Education, University of Skövde, Skövde, Sweden. anette.ekstrom-bergstrom@hv.se.; Department of Health Sciences, University West, Trollhättan, Sweden. anette.ekstrom-bergstrom@hv.se., Berg M; Institute of Health and Care Sciences, University of Gothenburg, Gothenburg, Sweden.; Centre for Person-Centred Care, University of Gothenburg, Gothenburg, Sweden., Buckley S; School of Public Health, The University of Queensland, Brisbane, Australia., Pajalic Z; Faculty of Health Sciences, Oslo and Akershus University College of Applied Sciences, Oslo, Norway., Hadjigeorgiou E; Faculty of Health Sciences, Cyprus, University of Technology, Limassol, Cyprus., Kotłowska A; Faculty of Health Sciences with Subfaculty of Nursing and Institute of Maritime and Tropical Medicine, Medical University of Gdańsk, Gdańsk, Poland., Lengler L; Midwifery Research and Education Unit, Hannover Medical School, Hannover, Germany., Kielbratowska B; Faculty of Medical Sciences, Medical University of Gdańsk, Gdańsk, Poland., Leon-Larios F; Faculty of Nursing, Physiotherapy and Podiatry, University of Seville, Seville, Spain., Magistretti CM; Department of Social Work Center for Health Promotion and Social Participation, Lucerne University of Applied Sciences and Arts, Luzern, Switzerland., Downe S; Research in Childbirth and Health (ReaCH) group, University of Central Lancashire, Preston, UK., Lindström B; Norwegian University of Science and Technology, Trondheim, Norway., Dencker A; Institute of Health and Care Sciences, University of Gothenburg, Gothenburg, Sweden.; Centre for Person-Centred Care, University of Gothenburg, Gothenburg, Sweden.
Jazyk: angličtina
Zdroj: BMC pregnancy and childbirth [BMC Pregnancy Childbirth] 2019 Aug 09; Vol. 19 (1), pp. 285. Date of Electronic Publication: 2019 Aug 09.
DOI: 10.1186/s12884-019-2365-9
Abstrakt: Background: Oxytocin is a key hormone in childbirth, and synthetic oxytocin is widely administered to induce or speed labour. Due to lack of synthetized knowledge, we conducted a systematic review of maternal plasma levels of oxytocin during physiological childbirth, and in response to infusions of synthetic oxytocin, if reported in the included studies.
Methods: An a priori protocol was designed and a systematic search was conducted in PubMed, CINAHL, and PsycINFO in October 2015. Search hits were screened on title and abstract after duplicates were removed (n = 4039), 69 articles were examined in full-text and 20 papers met inclusion criteria. As the articles differed in design and methodology used for analysis of oxytocin levels, a narrative synthesis was created and the material was categorised according to effects.
Results: Basal levels of oxytocin increased 3-4-fold during pregnancy. Pulses of oxytocin occurred with increasing frequency, duration, and amplitude, from late pregnancy through labour, reaching a maximum of 3 pulses/10 min towards the end of labour. There was a maximal 3- to 4-fold rise in oxytocin at birth. Oxytocin pulses also occurred in the third stage of labour associated with placental expulsion. Oxytocin peaks during labour did not correlate in time with individual uterine contractions, suggesting additional mechanisms in the control of contractions. Oxytocin levels were also raised in the cerebrospinal fluid during labour, indicating that oxytocin is released into the brain, as well as into the circulation. Oxytocin released into the brain induces beneficial adaptive effects during birth and postpartum. Oxytocin levels following infusion of synthetic oxytocin up to 10 mU/min were similar to oxytocin levels in physiological labour. Oxytocin levels doubled in response to doubling of the rate of infusion of synthetic oxytocin.
Conclusions: Plasma oxytocin levels increase gradually during pregnancy, and during the first and second stages of labour, with increasing size and frequency of pulses of oxytocin. A large pulse of oxytocin occurs with birth. Oxytocin in the circulation stimulates uterine contractions and oxytocin released within the brain influences maternal physiology and behaviour during birth. Oxytocin given as an infusion does not cross into the mother's brain because of the blood brain barrier and does not influence brain function in the same way as oxytocin during normal labour does.
Databáze: MEDLINE
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