2. Events prior to the birth of the placentaThird stage labor problems, associated with the placenta, which may occur prior to the actual birth of the placenta include the following:
In the majority of cases, the placenta separates spontaneously from its site of uterine attachement and is expelled from the vagina within the first 30 minutes after birth of the baby. In the section, Birth of the Normal Placenta, we described some common variations from normal which included a non-significant delay in separation due to minimal uterine powers and/or a placenta sited in the less contractile lower uterine segment.
We suggested that, in the absence of any evidence of bleeding, watchful waiting, with the abdominal hand over the uterus, would most often result in the spontaneous separation and birth of the placenta within the first 30 to 60 minutes after the baby is born.
In the circumstance of decreased uterine contractility, putting the baby to the mother's breast to nurse will stimulate maternal oxytocin release. This is usually sufficient to increase uterine contractions and cause the placenta to shear off the uterine wall and drop into the cervical opening to the vagina.
However, if there are no signs of separation, and no or minimal bleeding after the above procedures have been carried out, the birth attendant should consider the several possiblities for delay in detachment of the placenta and retraction of the placental site. The placenta may be unusually adherent to the implantation site due to scanty or absent decidua. This abnormal adherence may involve all of the cotyledons, only a few, or a single cotyledon.
There are three terms used to describe the degree of attachment of the placental villi to the myometrial layer of the uterus:
With total involvement there may be little or no bleeding from the uterus. It is apparent that attempts to manually removed the placenta will not be successful, as there is no cleavage plane to be created between the maternal surface of the placenta and the uterine wall. Moreover, attempting manual removal may result in massive hemorrhage and/or inversion of the uterus.
Since both of these events are life-threatening, physical manuvers or procedures should not be attempted. As long as there is not bleeding which needs to be immediately addressed there is time, hours or even days, in which to make a proper diagnosis and initiate safe treatment in an environment where a skilled obstetric surgeon, anesthesia, and aseptic technique are immediately available. If these are not available in the hospital where the birth has occurred, or the birth was in a freestanding birth center, clinic or home, the woman should be transferred to the nearest hospital able to provide these services.
The problem of separation will vary considerably depending on the number of cotyledons involved and the extent of the adherence. In some instances, only a very slight adherence in one small area may enable the removal of the placenta and its membranes by the use of Manual Removal of the Placenta. The presence of heavy bleeding indicates that at least partial separation has occured. The active bleeding demands immediate and life saving response. Manual removal should be attempted and may be successful in assisting the separation and delivery of the placenta.
The placenta may have successfully separated, but a small fragment or fibrous string, adherent membranes, or failure of uterine powers may keep the placenta from being expelled into the vagina. There will usually be active bleeding, which provides indication of the need for an immediate attempt at Manual Removal of the Placenta and any membranous fragments.
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