Induction of labour: Facilitation of labour onset, prediction of success and improving the induction process / Tan Peng Chiong
Labour is induced in about 25% of pregnancies demonstrating its importance in contemporary obstetric practice. The papers forming the thesis are grouped as follows surrounding the central theme of inducing labour: 1) Coitus as a home remedy and membrane sweeping as an office procedure to facilit...
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| Format: | Thesis |
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2014
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| Online Access: | http://studentsrepo.um.edu.my/4681/ http://studentsrepo.um.edu.my/4681/1/Final_Thesis_25Aug2014_MHA110030.pdf http://studentsrepo.um.edu.my/4681/2/PhD_MHA110030_TanPengChiong_2014.pdf |
| Summary: | Labour is induced in about 25% of pregnancies demonstrating its importance in
contemporary obstetric practice. The papers forming the thesis are grouped as follows
surrounding the central theme of inducing labour:
1) Coitus as a home remedy and membrane sweeping as an office procedure to
facilitate onset of labour
The works on coitus provide important lessons about human studies. The initial
promise from an observational study demonstrating an association of coitus with
earlier labour onset was not supported by the findings of two subsequent clinical trials
on coitus as an intervention. The secondary data analysis of the first trial also provide
evidence that coitus at term does not facilitate labour onset. The paper on serial
weekly membrane sweeping to facilitate labour onset in women desiring vaginal birth
after Caesarean did not demonstrate statistically significant results but the observed
effect is smaller than assumed.
2) Evaluation of sonographic predictors of successful induction of labour resulting in
vaginal delivery
The works on ultrasound parameters as predictors of successful labour induction
contributed to the developing literature. We confirmed that transvaginal ultrasound is
better tolerated than digital assessment for the Bishop Score. This can be important for
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maternal satisfaction in obstetric care. Transvaginal ultrasound measurement of
cervical length is probably a better predictor of labour inducibility than Bishop Score
but additional equipment and skill acquisition are needed. Our original study linking
membrane sweeping and cervical length changes as assessed by transvaginal
ultrasound demonstrate a positive association between postsweep cervical shortening
and subsequent vaginal delivery. Postsweep cervical shortening may be a marker of
cervical pliability leading to labour success.
3) Novel refinements of currently used labour induction regimens to improve
efficiency in high, mixed and low risk populations.
The work on membrane sweeping as an immediate adjunct to formal labour induction
is important as it confirms that adjunctive membrane sweeping reduces operative
delivery. Concurrent titrated oxytocin infusion and dinoprostone pessary in nulliparas
with intact membranes and unfavourable cervixes is a viable option based on our
largely positive findings. The few past trials on concurrent regimens all used quite
different regimens; any meta-analysis would be difficult to constitute and interpret. On
the other hand in nulliparas with unfavourable cervixes after term prelabour rupture of
membranes, labour induction with titrated oxytocin infusion is possibly better leaving
little rationale for a future concurrent regimen trial. The case for immediate titrated
oxytocin infusion following amniotomy for labour induction in parous women with
favourable cervixes is more balanced. Immediate oxytocin is quicker at achieving
vaginal delivery but minor abnormality in fetal heart rate tracing is also more
common. |
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