Stages of Labor:
The difficult process of giving birth is known as labor or parturition. It specifically refers to the procedure that begins with uterine contractions that result in cervical alterations that allow the fetus to be delivered vaginally and concludes with the delivery of the placenta.
When the fetus is between 37 and 42 weeks gestational, it is usually at this moment that labor starts. Before labor begins in the third trimester, a woman may see a plug of mucus and blood emerging from the cervix opening, often known as the BLOODY SHOW.
The amniotic sac may also rupture at other eras, a condition known as WATER BREAKING. Both of these have the ability to start labor and what are known as REAL LABOR CONTRACTIONS.
They must be differentiated from the milder and ineffective Braxton hicks contractions, sometimes known as practice contractions or other times more gentle false labor contractions.
True labor contractions begin as they become regular and intense, progressing in frequency, duration, and strength. These contractions may resemble waves that develop to a peak intensity before gradually fading away.
The cervix’s thick tissues are pulled by the contractions, which causes them to face or thin out.
This allows the fetus to exit the uterus to see the outside world. For first-time pregnancies, it typically takes 12 to 18 hours from the start of real contractions until the baby is delivered; for subsequent pregnancies, it typically takes half that amount of time. This period of time is extremely unpredictable.
Labor can be divided into three stages even though it is a continuous activity. Additionally, there are two phases to this first stage. The first phase, also known as the latent phase, is the initial stage and typically lasts up to 20 hours, or until the cervix enlarges to 6 cm.
The cervix initially dilates from zero (0) to roughly three centimeters and from 0% to 30% in phase due to erratic contractions that start out happening every 5 to 30 minutes.
Regular contractions that occur every 3 to 5 minutes and persist for at least a minute come next, causing the cervix to enlarge from 3 to 6 cm and to reach a phase of up to around 80%.
The cervix dilates from 6 to 10 cm and a phase to 100% during the active phase of labor, which starts at this point. The contractions can even overlap, with one starting before the last one is finished, as they are highly powerful, lasting between 60 and 90 seconds each with just thirty seconds to 2 minutes of rest in between.
Additionally, if it hasn’t already, the amniotic sac frequently ruptures at this point.
The second stage of labor, sometimes known as the PUSHING STAGE, begins now that the cervix is fully dilated. The baby’s head must pass through the mother’s pelvis during this stage, which depends on the three components of power, passenger, and passage.
Strong uterine contractions are referred to as POWER. The fetus is referred to as the PASSENGER, and the route that it must take through the bony pelvis is referred to as the PASSAGE.
Human babies have developed with infused skulls specifically so that their heads can grow as huge as possible and still effectively and safely make that trip through the pelvis into the outside world. The interaction between the baby’s head and the bony pelvis is so crucial.
The ease of this journey for the fetus depends on a number of different factors.
The size of the fetal head is the first important consideration. There is also the fetal attitude, which describes how the fetal body is flexed rather than the personality of the fetus.
The fetus is typically fully flexed when labor begins, which means that the chin is on the chest, the back is rounded, and the arms and legs are extended.
The pelvic inlet is where the sub-occipital pragmatic diameter, which is the smallest diameter at this position presents. Larger and partially flexed fetuses have a harder time passing through the passage.
Additionally, there is FETUS LIE, which explains the position of the fetus inside the uterus. The long axis of the fetus, which is also its spine, lies along the maternal long axis, the mother’s spine, making a longitudinal fetal Iie optimal.
These two positions, when the fetus is transverse or oblique and the fetal spine is perpendicular to the mother’s spine, can slow down the progress of labor.
Fetal presentation refers to the first fetal portion, also known as the presenting part, to descends into the pelvic inlet.
The most typical and effective presentation for simple delivery is a kind of cephalic presentation called the vertex, which also includes full head flexion. Cephalic, or headfirst, is the first type.
Additionally, there is the shoulder presentation, in which the shoulders come into view first, and the breech presentation, in which the head is up and the bottom feet or knees are present first.
The fetus adjusts its posture in a number of ways that are known as cardinal movements or mechanisms of labor in order to pass through the passage. The fetus first descends into the pelvic inlet, or inlet, in a downward motion.
Fetal station, which describes the relationship between the presenting portion and the mother’s ISCHIAL SPINE, is the degree of descent.
The fetus first goes from the pelvic inlet, which is stationed at roughly a -5 station, down to the ISCHIAL SPINE, which is stationed at zero; this position is referred to as engagement.
Next, the fetus moves into flexion, where its head encounters resistance from the pelvic floor and its chin presses against its chest.
The fetal shoulders then undergo internal rotation, which involves a 45-degree turn inward such that the broadest section of the shoulders lines up with the widest part of the pelvic inlet.
The fetal head changes from flexion to extension after passing under the symphysis pubis, which occurs at about +4 stations. Then, at about +5 stations, the fetal head moves to the side and emerges from the vagina.
The second stage of labor ends when the anterior shoulders, followed by the posterior shoulders, and then the rest of the body, pass under the symphysis pubis after the head has been delivered.
Restitution occurs when the head externally rotates so that the shoulders can pass through the pelvic outlet and under the symphysis pubis.
Following the delivery of the baby, the placenta is delivered during the third stage of labor.
The uterus hardens after the baby is delivered, and the placenta starts to detach from the uterine wall. Once no placental remains are found inside the uterus, it is carefully removed.
It is also referred to as the “FOURTH STAGE” a few hours after birth since there have been significant physiological changes, such as adaptation to blood loss and the beginning of uterine involution, in which the uterus starts to return to its pre-pregnancy form.
Summary:
Three distinct stages make up labor. When the cervix is fully effaced and dilated, the first stage is complete. It begins with actual labor contractions.
The pushing stage, which concludes with the baby’s birth, is the second stage. After the placenta is delivered, the third stage is complete.