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Maternal plasma levels of oxytocin during physiological childbirth - A systematic review with implications for uterine contractions and central actions of oxytocin
- Source :
- BMC Pregnancy and Childbirth, BMC Pregnancy and Childbirth, Vol 19, Iss 1, Pp 1-17 (2019)
- Publication Year :
- 2019
-
Abstract
- 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. © The Author(s). 2019 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/)
- Subjects :
- endocrine system
Uterine contractions
Physiological labour
Central effects
Reproduktionsmedicin och gynekologi
Births
B720
Infusion of synthetic oxytocin
Oxytocin
lcsh:Gynecology and obstetrics
Medical and Health Sciences
Plasma levels
Neurobiology
Pregnancy
Oxytocics
Obstetrics, Gynecology and Reproductive Medicine
Humans
lcsh:RG1-991
Labor, Obstetric
Parturition
Basic Medicine
A300
Birth
Female
hormones, hormone substitutes, and hormone antagonists
Research Article
Subjects
Details
- Language :
- English
- Database :
- OpenAIRE
- Journal :
- BMC Pregnancy and Childbirth, BMC Pregnancy and Childbirth, Vol 19, Iss 1, Pp 1-17 (2019)
- Accession number :
- edsair.pmid.dedup....1463577557986cd30da1cea600b53837