Labour & Delivery
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Research Clinician
Dr Penny SheehanPenny.Sheehan@thewomens.org.au
+61 3 8345 3752
Project Details
Project 1. What triggers labour
The process of birth is thought to be controlled by hormonal factors produced by tissues within the womb. The aim of this project is to investigate one of these hormones, in particular, a metabolite of progesterone called 5-beta-dihydroprogesterone. This study will help to improve our understanding of how normal labour occurs and may provide insight into how to prevent it from occurring prematurely. Blood samples are collected from women before, during and after labour, and also from women in premature labour and before term but not in labour. Tissue samples from the womb are also collected at the delivery of babies by Caesarean section for investigation using various molecular biology techniques.
Project 2. Failure to progress in labour - electrophysiological and molecular studies
Failure of the muscle of the uterus to contract strongly during labour results in protracted and exhausting labour and, in a significant percentage of cases, necessitates caesarian delivery. The aim of this study is to elucidate the mechanisms that may be responsible for the weak uterine contractions that underlie ineffective labour. Failure of the uterus to contract normally at term, ineffective labour, necessitates the intervention of caesarian delivery in as many as 5-10% of first pregnancies. Administration of oxytocin may augment weak uterine contractions and resolve ineffective labour in some cases. However, in many cases, successful vaginal delivery is not achieved by oxytocin infusion. The causes of ineffective labour remain obscure. In our recent studies of uterine contractility in tissues form a subset of the in-labour group appeared to divide the ineffective labour tissues further into three groups. One group contracted weakly to applied oxytocin. In another group, contractions were anomalously suppressed by prostaglandins that are normally strongly excitatory. The smooth muscle cells in tissues of the third group had unusually negative transmembrane potentials, making contractions difficult to achieve in the face of a wide range of stimuli. Elucidation of the mechanisms underpinning the failure to contract by these tissue is the main aim of this project
Researchers
- Dr Penny Sheehan, Research Clinician
- Professor Shaun Brennecke, Director
- Ms Janet Stevenson, Medical Laboratory Technician
- Ms Sue Duggan, Clinical Research Midwife
- Ms Moira Stewart, Clinical Research Midwife
Collaborators
- Prof Helena Parkington, Monash University
- Prof Christine East, Monash University
Funding
The research actiivities of the Pregnancy Research Centre (PRC) are funded by a variety of intramural and extramural sources. Since its formation in 1993, the PRC has secured over $15 Million in peer-reviewed, competetive national and international funding sources.
Research Outcomes
Recent publications relating to labour & delivery research in the PRC
Parkington HC, Stevenson J, Tonta MA, Paul J, Butler T, Maiti K, Chan EC, Sheehan PM, Brennecke SP, Coleman HA, Smith R. Diminished hERG K(+) channel activity facilitates strong human labour contractions but is dysregulated in obese women. Nature Communications 2014; 5:4108.
Wang R, Sheehan PM, Brennecke SP. Changes in myometrial expression of progesterone receptor membrane components 1 and 2 are associated with human parturition at term. Reproduction, Fertility, and Development. 2014 Sep 30. doi: 10.1071/RD13430. [Epub ahead of print]
Sheehan P, Rice GE, Brennecke SP. 5β-dihydroprogesterone and Human Preterm Labor. Open Journal of Endocrine and Metabolic Diseases (OJEMD). 2014; 4:128-135
East CE, Kane SC, Davey M-A, Kamlin CO, Brennecke SP. Protocol for a randomised controlled trial of fetal scalp blood lactate measurement to reduce caesarean sections during labour: the Flamingo trial. BMC Pregnancy and Childbirth. 2015; 15:285. doi: 10.1186/s12884-015-0709-7
East C E, Leader L R,Sheehan P, Henshall N E, Colditz P B, Lau R. Intrapartum fetal scalp lactate sampling for fetal assessment in the presence of a non-reassuring fetal heart rate trace. Cochrane Database of Systematic Reviews 2015; 2015, Issue 5.Art. No.: CD006174. DOI:10.1002/14651858.CD006174.pub3
Research Publications
Parkington HC, Stevenson J, Tonta MA, Paul J, Butler T, Maiti K, Chan EC, Sheehan PM, Brennecke SP, Coleman HA, Smith R. Diminished hERG K(+) channel activity facilitates strong human labour contractions but is dysregulated in obese women. Nature Communications 2014; 5:4108.
Wang R, Sheehan PM, Brennecke SP. Changes in myometrial expression of progesterone receptor membrane components 1 and 2 are associated with human parturition at term. Reproduction, Fertility, and Development. 2014 Sep 30. doi: 10.1071/RD13430. [Epub ahead of print]
Parkington HC, Tonta MA, Brennecke SP, Coleman HA. Contractile activity, membrane potential, and cytoplasmic calcium in human uterine smooth muscle in the third trimester of pregnancy and during labor. American Journal of Obstetrics and Gynecology, 1999; 181, 6, 1445-1451.
Parkington HC, Tonta MA, Davies NK, Brennecke SP, Coleman HA. Hyperpolarization and slowing of the rate of contraction in human uterus in pregnancy by prostaglandins E2 and F2a: involvement of the Na+ pump. Journal of Physiology, 1999; 514, 1, 229-243.