There are a great number of comprehensive, scientific and general, books and articles that cover Parturition, Birth or Childbirth.
Birth or parturition is a critical stage in development, representing in mammals a transition from direct maternal support of fetal development, physical expulsion and establishment of the newborns own respiratory, circulatory and digestive systems.
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Birth - Stage 1 |
Newborn infant |
These notes only cover the biological processes involved in birth fetal signaling changes and maternal signaling changes. Note that there is a growing worldwide trend in developed countries toward caesarean section delivery.
Page Links: Introduction | Some Recent Findings | Birth Models | Reading | Gestation Period | Preterm Birth | Birth Date Calculator | Birth Terms | References | Glossary
Other Pages: Respiratory Development - Birth |
Markovic D, Vatish M, Gu M, Slater D, Newton R, Lehnert H, Grammatopoulos DK. The onset of labour alters corticotropin-releasing hormone type 1 receptor (CRH-R1) variant expression in human myometrium: putative role of IL-1{beta} Endocrinology. 2007 Apr 12
Zakar T, Hertelendy F. Progesterone withdrawal: key to parturition. Am J Obstet Gynecol. 2007 Apr;196(4):289-96.
"In most subprimate placental mammals, the withdrawal of progesterone before the initiation of labor is manifest by a significant drop in circulating progesterone levels, which is due to either luteolysis or changes in placental steroidogenesis, which shunts precursors towards estrogen production. No such events can be demonstrated in human pregnancy."
The median duration of gestation for first births from assumed ovulation to delivery was 274 days (just over 39 weeks). For multiple births, the median duration of pregnancy was 269 days (38.4 weeks).
"...one should count back 3 months from the first day of the last menses, then add 15 days for primiparas or 10 days for multiparas, instead of using the common algorithm for Naegele's rule." Reference: Mittendorf R, Williams MA, Berkey CS, Cotter PF. The length of uncomplicated human gestation. Obstet Gynecol. 1990 Jun;75(6):929-32
Historically, Franz Carl Naegele (1777-1851) developed the first scientific rule for estimating length of a pregnany.
This topic has been separated into pages related to the whole signaling process overview.
There is a specific page online Premature Birth being currently prepared.
A study has shown that risks of preterm birth in low abnormal birth weight (intrauterine growth restriction) and high (large for gestational age) categories are 2- to 3-fold greater than the risk among appropriate-for-gestational-age infants.
In another study of placenta previa, low birth weight is due mainly to preterm delivery and to a lesser extent with fetal growth restriction.
(More? HSTAT - Management of Preterm Labor)
Reference: Lackman F, Capewell V, Richardson B, daSilva O, Gagnon R. The risks of spontaneous preterm delivery and perinatal mortality in relation to size at birth according to fetal versus neonatal growth standards. Am J Obstet Gynecol. 2001 Apr;184(5):946-53.
Ananth CV, Demissie K, Smulian JC, Vintzileos AM. Relationship among placenta previa, fetal growth restriction, and preterm delivery: a population-based study. Obstet Gynecol. 2001 Aug;98(2):299-306.
(More? Premature Birth)
Process Overview | Birth Abnormalities | Birth Caesarian | Clinical Growth Charts | WWW Links | ABC Health Reports
Amniotomy birth medical procedure thought to speed labor, where the amniotic sac is artificially ruptured using a tool (amniohook).
Breech fetal buttocks presented first and can also occur in different forms depending on presentation (complete breech, frank breech, footing breech, knee breech).
Decidual Activation increased uterine proteolysis and extracellular matrix degradation.
Dilatation opening of the cervix in preparation for birth (expressed in centimetres).
Effacement shortening or thinning of the cervix, in preparation for birth.
Forceps mechanical "plier-like" tool used on fetal head to aid birth.
Fetal Macrosomia clinical description for a fetus that is too large, condition increases steadily with advancing gestational age and defined by a variety of birthweights. In pregnant women anywhere between 2 - 15% have birth weights of greater than 4000 grams (4 Kg, 8 lb 13 oz).
Membrane Rupture breaking of the amniotic membrane and release of amniotic fluid (water breaking).
Presentation how the fetus is situated in the uterus.
Presenting part part of fetus body that is closest to the cervix.
Second stage of labour passage of the baby through the birth canal into the outside world.
Vacuum Extractor suction cap device used on fetal head to aid birth.
Vertex Presentation (cephalic presentation) where the fetus head is the presenting part, most common and safest birth position.
Links require internet connection.
NCBI Bookshelf
Health Services/Technology Assessment Text (HSTAT) Bethesda (MD): National Library of Medicine (US), 2003 Oct.
Reviews
Articles
Ochedalski T, Lachowicz A. Maternal and fetal hypothalamo-pituitary-adrenal axis: different response depends upon the mode of parturition. Neuro Endocrinol Lett. 2004 Aug;25(4):278-82.
Search PubMed Now: childbirth | parturition
International and Australian Population Statistics
WHO Normal Population Statistics
Global Perinatal and Maternal Causes of Death
Population Comparisons between Countries
Normal population statistics derived from a number of different sources (as shown on individual pages).
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Page 1 | birth page 2 | birth page 3 | birth page 4 | birth page 5 | birth page WWW
Home Page
Embryo stages
Fetal Dev
Dev Notes 1
Dev Notes 2
System Notes
Acknowledgements
Introduction
Birth Overview
Abnormalities
Caesarean
Apgar
Premature
Low Birth Weight
Placental Cord Clamping
Cardiovascular
Stillbirth and Perinatal Death
Molecular
Web Links
Movies
Class Notes
Serial Images
K12 Students
Abnormal
Embryology in the News
Histology
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School of Med Sci
UNSW Medicine
University of NSW
UNSW Cell Biology
NCBI Books
Dev Biol (Gilbert)
Given the extensive study of this biological process there is still much unknown about the timing, initiation and regulation of the birth process.
Some theories suggest a "placental clock" regulating through production of corticotrophin-releasing hormone may determine the length of gestation.
This page introduces only a few topic areas related to birth and should give you a feel for the topic.
Please email Dr Mark Hill if you wish to make a comment about this current project.
