Umbilical cord prolapse

Dr. Holbrook is a senior resident in the Department of Obstetrics and Gynecology at the University of New Mexico School of Medicine, Albuquerque.

Dr. Phelan is a professor in the Department of Obstetrics and Gynecology and the Medical Director for Labor and Delivery at the University of New Mexico School of Medicine, Albuquerque.  She is also a member of the Contemporary OB/GYN editorial board.

Neither author has a conflict of interest to disclose with respect to the content of this article.

Umbilical cord prolapse (UCP) is a well-known obstetric emergency in which the umbilical cord passes through the cervix at the same time as or in advance of the fetal presenting part. The cord is then prone to compression between the fetal presenting part and the surrounding soft tissues or bony pelvis, which can lead to fetal hypoxia. Although not a common obstetric emergency, UCP is one in which the initial response can make a difference in the quality of maternal and infant outcomes.

Incidence of UCP is estimated to be between 1.4 and 6.2 per 1000 pregnancies.¹ Although this has not changed in the last century, perinatal outcomes for UCP have improved significantly. Historically, UCP has been associated with poor neonatal outcomes, with perinatal mortality ranging from 32% to 47% in the early to mid 20th century.² Current rates of perinatal mortality in cases of UCP are estimated to be 10% or less.^1-4 The most likely explanations for these vastly improved outcomes are the increased availability of cesarean delivery and advances in neonatal resuscitation.

Diagnosis

UCP can be occult or overt. Occult prolapse occurs when the cord passes through the cervix alongside the fetal presenting part; it is neither visible nor palpable. In overt prolapse, the cord presents in advance of the fetus and is visible or palpable within the vaginal vault or even past the labia.

Prolapse of the cord often leads to cord compression which, in turn, leads to abnormal findings on fetal heart rate (FHR) tracings in 41% to 67% of cases.^3,5 These changes may present as a severe, sudden deceleration, often with prolonged bradycardia, or recurrent moderate-to-severe variable decelerations. The diagnosis of overt UCP is made on vaginal examination, which will reveal a palpable umbilical cord (usually a soft, pulsating mass) within or visibly extruding from the vagina. A confirmed diagnosis of occult UCP is rare, because it cannot be definitively diagnosed even when Doppler ultrasound imaging is employed. Attempts to identify occult prolapse with imaging could delay necessary treatment for this emergent condition. Occult UCP likely is the cause of some cases of urgent cesarean delivery for unexplained fetal bradycardia.

NEXT: RISK FACTORS >>

Risk factors

Several factors increase the risk of cord prolapse. The main precipitating event is rupture of membranes (ROM), either spontaneous or performed artificially by a healthcare provider. Most risk factors for UCP can be separated into two categories: spontaneous and iatrogenic (Table 1).

Spontaneous causes may be related to fetal factors, uterine distention, or pregnancy complications. Fetal risk factors include malpresentation, fetal anomalies, fetal growth restriction/small for gestational age, funic presentation, and cord abnormalities. Factors related to uterine distention include polyhydramnios, multiple gestation (although this may also be related to increased risk of malpresentation), and grand multiparity. Pregnancy complications that put the fetus at risk of UCP include preterm delivery and preterm premature rupture of membranes.^1-3,5

A number of iatrogenic causes also exist, some of which are related to routine procedures performed as part of normal labor management. These include artificial ROM (especially if the fetal head or presenting part is not engaged), placement of a fetal scalp electrode or an intrauterine pressure catheter, amnioinfusion, attempted rotation of the fetal head from occiput posterior to occiput anterior, and external cephalic version.^1-3,5

Approximately half the cases of UCP may be linked to iatrogenic causes, but iatrogenic cord prolapse does not appear to be clinically linked to poor outcomes.^5,6 This is because the procedures in question are generally performed on Labor & Delivery units, where continuous fetal monitoring and any necessary interventions are available. Furthermore, iatrogenic UCP can occur in cases in which risk factors may have led to a spontaneous prolapse without intervention. Studies seem to support this finding, because different regional obstetric practice styles have no effect on the incidence of UCP.⁵

Prevention

Although a large percentage of UCP cases are attributed to iatrogenic causes, there is no evidence that knowledge of risk factors can reduce the incidence of UCP.⁵ At the same time, it is important to be aware of the risks when undertaking the interventions previously described. We recommend avoiding amniotomy unless the fetal head is well-engaged, or if necessary, “needling” the bag for a slower, more controlled release of fluid.⁷ If the vertex is not well applied to the cervix, mild fundal pressure during placement of a fetal scalp electrode or intrauterine pressure catheter may help to minimize elevation of the vertex out of pelvis. Providers should exercise caution with any of these procedures and perform them only in cases in which other methods are inadequate.

UCP cannot be prevented, but subsequent fetal complications have been shown to often be preventable, with significant decreases in fetal morbidity and mortality when the condition is promptly and appropriately treated.⁵

NEXT: MANAGEMENT >>

Management

Cord prolapse results in fetal hypoxia, and if not rapidly treated, can lead to long-term disability or death.^2,3,8 Prompt delivery has been shown to improve outcomes.⁵ This means that cases of UCP should be delivered as quickly as possible, which generally means cesarean delivery. In rare cases, however, UCP can occur when delivery is near. If the provider believes that a vaginal delivery can be performed more rapidly than a cesarean delivery, it is certainly appropriate to proceed with vaginal delivery. Operative delivery should be considered if the FHR tracing shows concerning findings.

The mainstay of management for UCP is urgent cesarean delivery. From the time of diagnosis until cesarean can be performed, the fetal presenting part should be elevated to relieve pressure on the cord and arrangements should be made for urgent cesarean delivery. Specifics of management will vary depending on whether an operative delivery can be accomplished within 30 minutes (typically an in-hospital event) or there will be a delay of more than 30 minutes (an out-of-hospital event). Table 2 lists variations to consider in management, depending on location.

Elevation of the presenting fetal part. The key first step after identifying a UCP is to elevate the presenting fetal part off the prolapsed cord. This is generally performed manually, with the physician placing 2 fingers or an entire hand into the vagina to elevate the fetus off the cord. Care should be taken to avoid palpation of the cord because that may cause vasospasm, potentially leading to a worse outcome.² Placing the patient in steep Trendelenburg or in knee-chest position is believed to be helpful by taking advantage of gravity to further relieve pressure on the cord.⁹

In cases in which the interval to delivery is likely to be prolonged (that is, requiring maternal transport to a facility where cesarean delivery can be performed), bladder filling may be a better option. With this technique-commonly called Vago’s method, in reference to the physician who first described the technique-a Foley catheter is placed and the bladder is filled with 500 to 750 mL of saline, and then clamped. ¹⁰ The patient’s enlarging bladder provides upward pressure on the fetus, thus alleviating the compression on the cord. Vago described this as an alternative to manual elevation, which he described as “effective, but . . . unpleasant for the mother and wearying for the doctor.” He also noted that in his experience, filling the bladder tends to calm uterine contractions, which would certainly further relieve pressure on the cord. Over the years, studies have shown Vago’s method to be effective.^10,11 To employ this strategy requires that a cord prolapse tray be immediately available (Figure 1). Comparison of manual elevation of the presenting part versus bladder filling shows essentially equal outcomes between the 2 groups.¹² It should be noted that the combination of the 2 methods does not lead to any improvement over using either alone.

Funic reduction. Another method that has been used to treat cord prolapse is funic reduction, replacement of the cord back into the uterus by sliding it above the fetal presenting part. This is performed by placing the entire hand in the vagina and gently elevating the fetal head. The cord is then lightly elevated above the fetal head, preferably at its widest point, and replaced back into the uterus; the goal is that the cord should stay in the fetal nuchal region.

Before cesarean delivery became commonplace, funic reduction was a major part of management in cases of UCP. It is now rarely performed, however, because outcomes were worse than cesarean delivery. There has been some discussion of renewed interest in funic reduction, and Dr. Barrett notes that overall, he has had very good outcomes with this strategy.¹³ In our experience, the technique is difficult but it can sometimes be successful and is certainly worth an attempt. Nevertheless, we would not recommend delaying preparations for cesarean delivery while attempting to replace the cord.⁷

Tocolysis. Although not a primary treatment for UCP, tocolysis has also been described and it appears to be a useful adjunct.⁹ It is likely not necessary in cases in which urgent delivery can be performed, but it can certainly be employed if FHR decelerations persist after the primary procedures have been performed.

Other considerations. Another important consideration is keeping the cord moist. When delivery is imminent, this is less of a concern. But with a prolonged interval to delivery, the cord could dry out, which could lead to vasospasm and thus, potentially worse outcomes. Therefore, if the cord prolapses through the introitus, it should be gently replaced into the vagina. A moist tampon or 4 x 4 gauze can then be inserted gently into the vagina below the cord to help hold it in place.

In rare cases of UCP, contraindications to immediate delivery may exist. In cases of lethal fetal anomalies or absent fetal heart tones, exposing the mother to the risk of urgent cesarean delivery will lead to no benefit to the fetus and thus, should not be performed. Delivery at a previable gestational age falls into this same category, although the definition of previability will vary based on the capabilities of a neonatal intensive care unit (NICU) as well as institutional policies.

It is important to note that there are case reports of UCP at a previable gestational age that were managed expectantly and successfully prolonged pregnancy to viable gestational age.^2,14 Cases of multiple gestations with prolapse of one cord at a periviable gestational age present difficult clinical dilemmas; the risks to each fetus must be discussed in detail but quickly with the patient to make the best management decision.

NEXT: OUTCOMES >>

Outcomes

Despite the potential for extremely poor outcomes, most neonates born after experiencing UCP do very well, especially if delivery is achieved within 30 minutes.⁵ The literature shows improved outcomes for cases of UCP that occur when the patient is already in the hospital, even if the fetus is not being monitored.³

One study has shown team training exercises to be beneficial in decreasing the mean diagnosis-to-delivery interval in cases of UCP.¹⁵ In addition, although this study was small and the results did not reach statistical significance, there was a trend toward improved Apgar scores and fewer NICU admissions. It appears that such exercises may lead to improved neonatal outcomes. These drills should stress both the steps taken prior to arrival in the operating suite and the role of all members of the team in facilitating an efficient and safe urgent/crash cesarean delivery.

Summary

Umbilical cord prolapse is a well-known obstetric emergency that requires prompt delivery to avoid potentially devastating fetal outcomes. Diagnosis is made by the presence of a palpable, pulsating mass within the vagina or visibly extruding from the introitus. It is often accompanied by sudden, severe FHR decelerations. Risk factors for UCP include malpresentation, prematurity, low birth weight, polyhydramnios, and a number of iatrogenic causes related to routine labor interventions. There is no evidence that UCP can be prevented, but rapid diagnosis and delivery have been shown to be advantageous.

Once UCP is diagnosed, the fetal presenting part should be manually elevated off the cord, the patient placed in knee-chest or steep Trendelenburg position, and preparations made for cesarean delivery, unless vaginal delivery is imminent. In cases in which the time to delivery is anticipated to be prolonged, backfilling the bladder with approximately 500 mL of saline can safely be substituted for manual elevation of the presenting part. Figure 2 presents an algorithm for management of UCP. Team training exercises have been shown to shorten the interval between diagnosis and delivery and may lead to improved neonatal outcomes.

If managed improperly, UCP can lead to significant fetal morbidity or mortality. Prompt, appropriate management of this condition, however, has been shown to have favorable overall outcomes.

References

1. Kahana B, Sheiner E, Levy A, et al. Umbilical cord prolapse and perinatal outcomes. Int J Gynaecol Obstet. 2004;84:127–132.

2. Lin MG. Umbilical cord prolapse. Obstet Gynecol Surv. 2006;61:269–277.

3. Koonings PP, Paul RH, Campbell K. Umbilical cord prolapse. A contemporary look. J Reprod Med. 1990;35:690–692.

4. Boyle JJ, Katz VL. Umbilical cord prolapse in current obstetric practice. J Reprod Med. 2005;50:303–306.

5. Murphy DJ, MacKenzie IZ. The mortality and morbidity associated with umbilical cord prolapse. Br J Obstet Gynaecol. 1995;102:826–830.

6. Usta IM, Mercer BM, Sibai BM. Current obstetrical practice and umbilical cord prolapse. Am J Perinatol. 1999;16:479–484.

7. Holbrook BD, Phelan ST. Umbilical cord prolapse. Obstet Gynecol Clin North Am. 2013;40:1–14.

8. Critchlow CW, Leet TL, Benedetti TJ, Daling JR. Risk factors and infant outcomes associated with umbilical cord prolapse: a population-based case-control study among births in Washington State. Am J Obstet Gynecol. 1994;170:613–618.

9. Katz Z, Lancet M, Borenstein R. Management of labor with umbilical cord prolapse. Am J Obstet Gynecol. 1982;142:239–241.

10. Vago T. Prolapse of the umbilical cord: a method of management. Am J Obstet Gynecol. 1970;107:967–969.

11. Caspi E, Lotan Y, Schrever Pl. Prolapse of the cord: reduction of perinatal mortality by bladder instillation and cesarean section. Isr J Med Sci. 1983;19:541–545.

12. Bord I, Gemer O, Anteby EY, Shenhav S. The value of bladder filling in addition to manual elevation of presenting fetal part in cases of cord prolapse. Arch Gynecol Obstet. 2011;283:989–991.

13. Barrett JM. Funic reduction for the management of umbilical cord prolapse. Am J Obstet Gynecol. 1991;165:654–657.

14. Leong A, Rao J, Opie G, Dobson P. Fetal survival after conservative management of cord prolapse for three weeks. BJOG. 2004;111:1476–1477.

15. Siassakos D, Hasafa Z, Sibanda T, et al. Retrospective cohort study of diagnosis-delivery interval with umbilical cord prolapse: the effect of team training. BJOG. 2009;116:1089–1096.