Third stage of labor: From delivery of infant to delivery of the placenta
(upper limit of normal is 30 min). Abnormally retained placenta: Third stage of labor that has exceeded 30 min. Uterine inversion: "Turning inside out" of the uterus, whereupon the fundus of the uterus moves through the cervix, into the vagina (Figure 3-1). Signs of placental separation: Cord lengthening, gush of blood, globular uterine shape, and uterus lifting up to the anterior abdominal wall.
After a vaginal delivery, 95% of women experience spontaneous placenta separation within 30 min. Because the uterus and placenta are no longer joined, the placenta usually is in the lower segment of the uterus, just inside the cervix, and the uterus often is contracted. The umbilical cord lengthens because the placenta has dropped into the lower portion of the uterus. The gush of blood represents bleeding from the placental bed, usually coinciding with placental separation. If the placenta has not separated, excessive force on the cord may lead to uterine inversion. Massive hemorrhage usually results; thus, in this situation, the practitioner must be prepared for rapid volume replacement. Although it was classically taught by some that the shock was out of proportion to the actual amount of blood loss, this is not the case. In other words, shock is due to massive hemorrhage!
The best method for averting a uterine inversion is to await spontaneous separation of the placenta from the uterus before placing traction on the umbilical cord. Even after one or two of the signs of placental separation are present, the operator should be cautious not to put undue tension on the cord. At times, part of the placenta may separate, revealing the gush of blood, but the remaining attached placenta may induce a uterine inversion or traumatic severing of the cord. The grand-multiparous patient with the placenta implanted in the fundus (top of uterus) is at particular risk for uterine inversion. Placenta accreta, an abnormally adherent placenta, is also a risk factor.
With the diagnosis of an inverted uterus, immediate assistance—including that of an anesthesiologist—is essential because a uterine relaxation anesthetic agent, such as halothane (for uterine replacement), and/or emergency surgery may be necessary. If the placenta has already separated, the recently inverted uterus sometimes can be replaced by using the gloved palm and cupped fingers. Two intravenous lines should be started as soon as possible and preferably prior to placental separation because profuse hemorrhage may follow placental removal. Terbutaline or magnesium sulfate also can be used to relax the uterus if necessary prior to uterine replacement. Upon replacing the uterine fundus to the normal location, the relaxation agents are stopped and then uterotonic agents, such as oxytocin, are given. Placement of the clinician's fist inside the uterus to maintain the normal structure of the uterus is important.
Note: Even with optimal treatment of uterine inversion, hemorrhage is almost a certainty.
|3.11 Which of the following placental implantation sites would most likely predispose to an inverted uterus?
E. Lower segment
[3.2] Which of the following would be the next step after a 30-min third stage of labor?
A. Initiate oxytocin
B. Wait an additional 30 min
D. Attempt a manual extraction of the placenta
E. Estrogen intravaginally
[3.3] Which of the following is most likely to be a risk factor for uterine inversion?
A. Long umbilical cord
B. Atonic uterus
C. Placental abruption
D. Attenuated umbilical cord
[3.41 A 33-year-old G5 P5 woman who is being induced for preeclampsia delivers a 9-lb baby. Upon delivery of the placenta, uterine inversion is noted. The physician attempts to replace the uterus, but the cervix is tightly contracted, preventing the fundus of the uterus from being repositioned. Which of the following is the best therapy for this patient?
A. Vaginal hysterectomy
B. Diihrssen's incisions of the cervix
C. Halothane anesthesia
D. Discontinue magnesium sulfate
E. Infuse oxytocin intravenously
[3.11 A. A fundally implanted placenta predisposes to uterine inversion.
[3.2] D. After 30 min. the placenta is abnormally retained, and a manual extraction is generally attempted.
[3.3] B. An attenuated umbilical cord leads to severing of the cord with traction and in a way protects against uterine inversion, whereas an unusually sturdy cord may predispose to uterine inversion. An atonic uterus predisposes to uterine inversion.
]3.4] C. A uterine relaxing agent (such as halothane anesthesia) is the best initial therapy for a nonreducible uterus. Diihrssen's incisions are used to treat the entrapped fetal head of a breech vaginal delivery.
Was this article helpful?