Hello, welcome to Medical Advice Channel. in this article we’re going to talk about the stages of labour. Before we start, I would request you to subscribe to our newsletter, so that you are the first to be notified when new articles are released.
First, let us recap the physiology and some terminologies. So, normal labour usually occurs after 37 weeks. A full term birth would refer to delivery occurring between 37 to 42 weeks gestation, but during certain situations during certain circumstances, Labour might occur before 37 weeks, if it’s before 37 weeks, we call this premature labour.
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Stages of labour
Now remember, labour is divided into three stages, stage one, stage two and stage three. Now, let’s just say a woman is going into labour. She’s about to deliver what is happening. Well she will enter stage one of labour. Stage one of labour can be divided into two phases. The latent phase, also known as the initial phase, and the active phase.
So when labour begins, the cervix is actually being stretched by the baby due to release of certain factors. The stretching of the cervix will actually send signals to the brain. It will send signals to the hypothalamus and the posterior pituitary gland to release a hormone called oxytocin. Oxytocin will travel to the uterus via the blood and start stimulating uterine contractions. What’s more, when the foetus or the baby is ready to come out, it will also release things from itself, which will also stimulate the placenta to secrete chemicals called prostaglandins.
These prostaglandins will stimulate uterine contraction as well. So with all this uterine contraction by the oxytocin and by the prostaglandin, the cervix will actually slowly stretch out even more, and the cycle continues. It’s a positive feedback loop.
The contractions of the uterus are more constant they come in waves, regular rhythm, the contractions during labour is actually defined as being regular painful contractions. The cervix stretches slowly and you begin to see thinning of the cervix, which is effacement of the cervix, which will progress to the final outcome, cervix dilatation.
This cervix is now three centimeters dilated. I am now drawing the cervix, looking at it from the front. So the vaginal rule is at the bottom here and as you can see the cervix is not dilated here, but as the labour progresses, the cervix will dilate. Here the cervix is about three centimeters dilated once the cervix opens to about three centimeters in diameter or some sources say four centimeters in diameter, diameter, the latent or the initial phase of stage one of labour will then enter the active phase of stage one of labour in the active phase of stage one of labour the cervix will just continue to dilate. Your contractions are regular and more painful. The cervix is said to be fully dilated when it is 10 centimeters.
This is where you can see crowning of the baby’s head. So looking at the cervix from the front again, here, you can see the baby the placenta and the uterus. The uterus is where the baby is in. And this is crowning with a cervix is fully dilated and you can see the head of the baby coming down and this is the vaginal wall. It is really important to know that babies usually are delivered head first, but in some situations the foot or the legs can come first this is called breech position. Babies in a breech position can be can be delivered from the vagina, but often they are delivered via caesarean section because of the risks of complication has for normal delivery. The uterus is contracting all this time remember, because of the oxytocin and the prostaglandins recapping stage one, stage one is divided into the latent and active phase.
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Regular painful contractions with thinning of thinning effacement of the cervix is what happens in stage one until the cervix reaches 10 centimeters dilatation or full dilatation of the cervix. After stage one it will the Labour will progress to stage two and stage two is from full cervix dilatation until the baby is born, basically in stage two of labour This is where the mother is delivered from the baby. Here is the umbilical cord. Here is the placenta and here is the rectum of the mother. And here you have a fully dilated cervix which is about 10 centimeters in diameter.
During this time, the uterus is still having regular painful contractions. Once the baby is born, it the Labour will then enter stage three. Stage three of labour is essentially the delivery of the placenta. And here is the umbilical cord which is the connection between the baby and the placenta. In stage three of labour the placenta is slowly detaching from the uterine lining. The uterus is still contracting at this stage. And actually during this time, the mother is given an injection to stimulate the delivery of the placenta.
The placenta has to be carefully delivered because it can cause hemorrhage, if not delivered properly. Once the baby is out, of course clamps are put on either side of the umbilical cord and then the umbilical cord is cut. It is also routine to get blood from the umbilical cord for analysis of PAH blood is taken from the umbilical artery and the umbilical vein. Thank you for watching. I think I’ll have a video that goes into detail specifically at stage one. of labour, which is again, the first stage of three once you actually get into medical school he wants to know