Childbirth is as knownparturition, it usually occurs within 15days of the calculated due date (280 days from LMP). The parturition means aprocess of delivering the baby and placenta from the uterus to the vagina tothe outside world called labour and delivery. There are series of events thatpropel the infant from the uterus, are referred to collectively as stages oflabour. The precise trigger for labour is not clear because some women maybeoverdue more likely if it is a first baby.
(Abbott,2016 )Human chorionic gonadotropin(HCG): stimulates the production of oestrogen and progesterone within theovary, production of this hormone diminishes once the placenta is mature enoughto take over oestrogen and progesterone production which are secret by the corpusluteum. (Abbott,2016)Oestrogens help regulatelevels of progesterone and prepare the uterus for the baby, progesteronecontains high levels of hormones which prevent uterine contractions while thebaby is still developing and therefore decrease, for labour to occur. Bypreventing contractions of the uterus. (Braxton hick’s contractions), painfulcontractions accompanied by thinning and the opening of the cervix up to 4cm,lasting 35-45 seconds and occurs during the latent phase of the first stage oflabour, that may last for a very long time, especially for first time mums andthe length of this phase can range from six hours to two-three days. ( Abbott,2016 )As oestrogen begins tostimulate uterine contractions, the pituitary gland releases hormone from themother called oxytocin hormone that stimulates contractions of the uterusduring achieving childbirth and labour that stimulates the placenta and produceprostaglandins, tissue hormone that helps start labour and used to inducedlabour. These contribute to the decrease of progesterone level, initiatinglabour along with the relaxin hormone which relaxes the muscle of the cervix,in the final phase of the first stage of labour is transition stage, causingthe cervix to dilate from about 4 centimetres to 7 centimetres (10 centimetres,making room for the baby to pass through), indicating fully dilated cervix, usually 6-12 hours orlonger. Leading to active labour in the first stage of labour.
Which leads to theexpulsion of the foetus from the mother’s uterus in the second stage of labour,this stage takes as long as 2 hours, it is typically 50 minutes in a firstbirth and around 20 minutes in subsequent births. (Petty, 2010)However, the final stretchof growth stretches the uterus to its limits which put a physical stress, onboth the baby and the uterus, causing the releases of a stress hormone calledcorticotropin-releasing hormone (CRH) and cortisol, increase during the lastfew days and weeks of gestation. When it rises, it triggers a rise in thesteroid hormone called estriol a form of oestrogen that is major duringchildbirth. which inhibits the synthesis of progesterone by the placenta andprepares the smooth muscles of the uterus for labour, leading to the thirdstage of labour in the delivery of the baby ending with the delivery of theplacenta and the empty bag of waters that are attached to the placenta(membranes).
A structure or tissue, such as the chorion, amnion sac that comesaway as the Uterus (womb) contracts down after birth. This is the shorteststage and usually accomplished 15 minutes after the birth of the baby. (Petty, 2010 )Foetal circulation andchanges also occur before birth, when the foetus is not capable of respiratoryfunction and therefore relies on the maternal circulation to carry out gas,nutrient and waste exchange. The foetal and maternal blood never mix, instead,the interface at the placenta because nutrient and oxygen are passed over bydiffusion only and if the mothers and foetus blood mixed, it could be deadlyfor both of them. As a result, the liver and the lungs are non-functional, anda series of shunts exist in the foetal circulation so that these organs arealmost completely by-passed. (Rudolph,2005)After birth, during thefirst stage of labour blood occurs in the Ductus venosus a trumpet-shapedvessel, provides a means for oxygenated umbilical vein blood to bypass thesinusoids of the liver.
The amount of blood passing through the vessel seems tobe regulated by a sphincter mechanism. For example, to prevent an excessivevenous return to the right side of the heart during uterine contractions, thereis a relative contraction of the ductus venosus. (Abbott,2016) This flows into the rightatrium and is directed towards the foramen ovale, a small hole located in theseptum of the heart, which is the wall between the two upper chambers of theheart (atria) with an anatomicadaptation in the foetus that allow oxygenated blood coming from the umbilicalvein through the inferior vena cava to bypass the pulmonary circulation. It ismixed with a small volume of blood returning from the non-functional lungsthrough the pulmonary veins and passes into the systemic circulation therebybypassing the lungs.
The following structures pass through foramen ovale: Mandibularnerve. The motor root of the trigeminal nerve. Accessory meningeal artery(small meningeal or peridural branch, sometimes derived from the middlemeningeal artery). (Huggon,2005) While the ductus arteriosus, also called theductus Botalli, is a temporary blood vessel connecting the pulmonary artery(the main heart vessel leading to the lungs) to the proximal descending aorta(the main blood vessel of the body). It allows most of the blood from the rightventricle to go around the foetus’s fluid-filled non-functioning lungs beforebirth.
Most of the blood in the aorta is then returned to the placenta foroxygenation through the umbilical arteries. Blood is emptied into the aortaafter the artery head has branched off through ensuring that the brain receiveswell-oxygenated blood. (Huggon ,2005 )Changes at and after birthoccur when the pressure changes due to inflation of the lungs and the increasedflow through the pulmonary arteries close the foramen ovale and the ductusarteriosus muscular wall contracts and close and is effectively obliteratedwithin 2 months, becoming the ligamentum arteriosum. The ductus venosus becomesthe ligamentum venosum (passing around the caudate lobe of the liver), and theintra-abdominal umbilical vein becomes the ligamentum teres.The umbilicalarteries become obliterated and form the medial umbilical ligaments (not to beconfused with the median umbilical ligament which is the obliterated remains ofthe urachus). (Huggon ,2005 )Lactation is under endocrinecontrol. The two main hormones involved are prolactin and oxytocin.
Prolactinis the hormone that stimulates mammary gland development and stimulates milkproduction called lactogenesis, the functional change of the breasts to secretemilk. During pregnancy, the body prepares for lactation by stimulating thegrowth and development of branching lactiferous ducts and alveoli lined withmilk-secreting lactocytes. ( Faye,2010 ) By the end of the 6 months,the mammary glands are fully developed, and gland cells begin to produce asecretion known as colostrum. These functions are attributable to the actionsof several hormones, including prolactin. Following the first two or three daysof childbirth, mammary gland secretion of breast milk suckling triggers andStimulated tactile receptors stimulate the release of oxytocin from theposterior lobe of the pituitary gland. Oxytocin causes contraction of themyoepithelial cells in the walls of the lactiferous ducts to squeeze milk fromalveoli and milk is ejected. ( Faye,2010)The delivery of the placentaand the resulting dramatic reduction in progesterone, oestrogen, and humanplacental lactogen levels stimulate milk production.
The milk produced in thefirst postpartum days contains more protein and less fat than breast milk, andmany of the proteins are antibodies that may help the infant fight offinfections until its own immune system develops. (Faye,2010) There are other differenthormones involved, such are, Human placental lactogen (HPL ), that stimulatesmilk glands in the breast, in anticipation of breastfeeding.Mammogenesis, whichis the growth of the breast. Galactopoiesis, responsible for maintaining theproduction of milk, and involution is the termination of milk production.
(Faye,2010 )Mature milk changes from thebeginning to the end of a feeding, whereas, Foremilk quenches the infant’sthirst, whereas hind milk satisfies the infant’s appetite. The colostrum isyellow in colour and thick and the mature milk is white in colour and thin.Whereas, breast milk is roughly divided into 2 stages. It first comes out inabout a week after childbirth is called colostrum and one after that is calledmature milk.
While colostrum is yellow in colour and thick. At the beginning,it comes out just like oozing from the nipples. As the baby suckle, thequantity gets increased. And after 7-10days, the colour of breast milk becomeswhite in colour and thin.
The quantity of it increases gradually and thebreasts come to be bloated, so it is happening that breast milk comes out from nipplesa lot. (Faye,2010 )