Labor is a coordinated efficient sequence of involuntary uterine contractions that results in effacement and dilatation of the cervix and voluntary bearing down efforts of the mother leading to the expulsion per vaginum of products of the conceptus. There are 3 stages of labor.
Labor is a natural process where a mother brings her baby to this world. It might be an emotionally and physically stressful event for the mother. Knowing about the science and stages of labor will help you to understand what is normal and that will help you to alleviate your stress.
What are the criteria to say labor is normal?
- It should be at term (37 – 42 weeks of pregnancy)
- Spontaneous onset (start by itself)
- Vertex presentation (the baby should come with his or her head and should be vertex presentation)
- No prolongation of labor phases
- Natural termination with minimal aid
- Without any complication both to the mother and the baby
But before we discuss stages of labor, we should first understand how labor starts at the expected time.
There are 4 phases of pregnancy.
Phase 1 – Uterine Quiescence and cervical softening
It makes 95% of the pregnancy.
At this time uterus is unresponsive to uterotonic. Progesterone is the main hormone here.
This phase is all about making the uterus comfortable for the fetus.
Phase 2 – Uterine awakening or activation
This phase is preparation for labor. it comprises the last 6 – 8 weeks of pregnancy.
Expression of contraction associated protein-like oxytocin receptors, Pg receptor, and gap junction protein. and the formation of the lower uterine segment starts. There will be collagen change in the cervix too. It is called cervical ripening.
Phase 3 – Labor
Coordinated uterine contraction and cervical change started here. uterus become more responsive to oxytocin.
Phase 4 – involution
It is the 1st hour after placental expulsion. At this point, milk lactogenesis was established. Oxytocin has a great role here.
So labor is phase 3 of pregnancy. The uterus becomes more responsive to oxytocin. So coordinated uterine contraction takes place. And that makes the cervix dilate.
labor has 3 stages. let’s see them one by one.
- First stage – Cervical dilatation and effacement
- Second stage – Delivery of the fetus
- Third stage – Delivery of the placenta
The First Stage of Labor – Cervical Dilatation and Effacement
The first stage is where the actual labor takes place. It has 2 phases.
- Latent phase and
- Active phase
During the latent phase, the cervix dilates up to 4 cm and almost fully effaced. Then during the active phase, the cervix dilates up to 10cm (fully dilate).
On average, the first stage of labor takes up to 20 hours for first-time labor. But it highly depends on strength of uterine contraction (you should have 2 – 5 contractions lasting 40 – 50 second each) and parity (if this is your first labor, you may last longer compared to a multiparous mother).
The Second Stage of Labor – Delivery of the Fetus
After the cervix is fully dilated and effaced, the next step is delivery.
In this stage of labor, some factors determine the progression of labor. Some of the factors are:
- Uterine contraction – The stronger the contraction, the quicker the process.
- Maternal pushing effort – You should synchronize it with uterine contraction. Contraction usually comes every 2 minutes in the second stage of labor so you should push hard and without interruption.
- Positioning is important at this stage. You should be in a lithotomy position and open your pelvis as wide as possible.
The hard part of the baby is his/ her head. So it is difficult to pass the head. Once the head pass, the rest of the body should deliver within seconds. You might get episiotomy if your vagina is too narrow to pass the baby head (especially if it is your first time).
After your baby head is born, then your doctor will assist to bring out the rest of the body.
The midwife will immediately do the APGAR score (on the 1st and 5th minute) to assess the baby if the baby needs medical attention to help the baby adjust to the new environment.
If the baby cries as soon as it is born, that is good. But if not, suctioning, physical stimulation, and resuscitation might be necessary. Luckily 95% of newborns will adjust to the new environment with no additional help.
The second stage of labor usually lasts 30 minutes (in multiparous mother) and 1 hour (in first-time labor). Pain management might prolong the process.
Third Stage of Labor – Delivery of the Placenta
After your baby is born, the last stage is to deliver the placenta.
If you wait for it, the placenta will be delivered in 30 minutes due to uterine contraction after the baby is born. But currently, we use active management of the third stage of labor to decrease bleeding risk. So
- Oxytocin will be given (IM injection or IV infusion which helps to facilitate uterine contraction and stop bleeding and prevent Postpartum hemorrhage).
- Then gentle pulling pressure will be applied to the placenta and counter pressure will be applied to the uterus (the doctor will put his hand on to your lower abdomen or suprapubic place) to avoid uterine inversion along with the placenta.
- Then the mother will be kept for some hours to assess if there is any bleeding. During that time the baby should be with the mother and start breastfeeding within minutes after birth if the mother decides to breastfeed (highly recommended).
After the placenta delivers, you should lie down for some time and start to breastfeed your baby as soon as possible. You will discharge after 6 – 12 hours if there are no complications.