Published 22 October 2008, doi:10.1136/bmj.a1940
Cite this as: BMJ 2008;337:a1940

Endgames

Picture quiz

Acute intrapartum obstetric emergency

¹ Coombe Women and Infants University Hospital, Dublin 8, and Trinity College Dublin, Ireland, ² Coombe Women and Infants University Hospital

A 30 year old primigravida was admitted in spontaneous labour at term. Vaginal bleeding was seen after spontaneous rupture of the membranes, and shortly afterwards a profound fetal bradycardia was recorded on cardiotocography. A "crash" emergency caesarean section was performed with delivery of a live male infant in good condition, weighing 3620 g. Apgar scores were 9 at one minute and 10 at five minutes with normal paired cord blood samples. Figure 1 shows the placenta after delivery.

View larger version (111K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 1 Image of the placenta after delivery

Questions

1. What is the diagnosis?

2. What is the ideal emergency management?

3. What risk factors are associated with this condition?

Answers

Short answers

1. Rupture of a vasa praevia is the most likely diagnosis.

2. The patient should be prepared for immediate delivery by caesarean section and the neonatologist should be informed of the possibility of neonatal hypovolaemia as a result of fetal exsanguination.

3. Risk factors include placenta praevia, velamentous cord insertion, and a multilobed placenta.

Long answers
1. Diagnosis
Rupture of a vasa praevia is the most likely diagnosis. Vasa praevia is an uncommon condition that occurs when fetal blood vessels unprotected by placental tissue or umbilical cord traverse the lower uterine segment in advance of the presenting part (fig 2). In addition, fig 2 shows a velamentous cord insertion (where the umbilical cord inserts directly into the membranes rather than the placenta), an important risk factor for vasa praevia. One of the unprotected vessels ruptured when the membrane ruptured, and this resulted in vaginal bleeding and fetal bradycardia.

View larger version (112K): [in this window] [in a new window] [PowerPoint Slide for Teaching]   Fig 2 Image of the patient’s placenta showing fetal blood vessels unprotected by placental tissue or umbilical cord traversing the lower uterine segment in advance of the presenting part and a velamentous cord insertion

 
The incidence of vasa praevia is 1 in 3000 deliveries to 1 in 6000 deliveries, but it increases to 1 in 300 deliveries with in vitro fertilisation.^{1 2 3} Recent attention has been focused on prenatal diagnosis of this condition, but the obstetrician and midwife must be aware of the potential for an acute presentation of undiagnosed vasa praevia during labour. The classic triad are membrane rupture, vaginal bleeding, and fetal bradycardia. Before membrane rupture, fetal vessels may be felt coursing over the membranes by the experienced observer. A speculum examination or amnioscopy may also show or confirm the presence of vasa praevia.

If the vessels are ruptured, the fetal loss rate is 75-100% as a result of exsanguination.⁴ Compression of the abnormal vessels, which compromises the placental circulation, may also result in fetal compromise or death. The main risk to the mother is that of bleeding and operative delivery, but maternal blood loss is usually minimal and not life threatening.

2. Emergency management
The infant should be delivered immediately by emergency caesarean section. The consultant obstetrician and paediatrician should be summoned. The perinatal mortality rate with ruptured vessels is extremely high. Newborn survivors often require resuscitation and transfusion.⁵

3. Risk factors
Any condition where the vessels run close to the cervix may be linked to vasa praevia. The two main causes of vasa praevia are velamentous cord insertion (where the umbilical cord inserts directly into the membranes rather than the placenta) and succenturiate or multilobed placentae (where the vessels cross between the lobes and are thus exposed).^{2 6}

Occasionally a vessel that courses over the edge of a marginal placenta or a placenta praevia may become a vasa praevia after the placenta extends over a more vascularised area and the cotyledons that were praevia involute.^{2 7 8} Other risk factors include multiple pregnancy⁹ and in vitro fertilisation.³

Cite this as: BMJ 2008;337: a1940

Provenance and peer review: Commissioned; externally peer reviewed.

Patient consent obtained.

References

1. Catanzarite V, Maida C, Thomas W, Mendoza A, Stanco L, Piacquadio KM. Prenatal sonographic diagnosis of vasa previa: ultrasound findings and obstetric outcomes in ten cases. Ultrasound Obstet Gynecol 2001;18:109-15.[CrossRef][Web of Science][Medline]
2. Lee W, Lee VL, Kirk JS, Sloan CT, Smith RS, Comstock CH. Vasa previa: prenatal diagnosis, natural evolution, and clinical outcome. Obstet Gynecol 2000;95:572-6.[CrossRef][Web of Science][Medline]
3. Schachter M, Tovbin Y, Arieli S, Friedler S, Ron-El R, Sherman D. In vitro fertilization is a risk factor for vasa praevia. Fertil Steril 2002;78:642-3.[CrossRef][Web of Science][Medline]
4. Heckel S, Weber P, Dellenbach P. Benckiser’s haemorrhage. 2 case reports and a review of the literature. J Gynaecol Obstet Reprod (Paris) 1993;22:184.
5. Oyelese Y, Catanzarite V, Prefumo F, Lashley S, Schachter M, Tovbin Y, et al. Vasa previa: the impact of prenatal diagnosis on outcomes. Obstet Gynecol 2004;103:937-42.[Web of Science][Medline]
6. Baulies S, Maiz N, Munoz A, Torrents M, Echevvaria M, Serra B. Prenatal ultrasound diagnosis of vasa praevia and analysis of risk factors. Prenat Diagn 2007;27:595-9.[CrossRef][Web of Science][Medline]
7. Oyelese Y, Chavez MR, Yeo L, Giannina G, Kontopoulos EV, Smulian JC, et al. Three-dimensional sonographic diagnosis of vasa previa. Ultrasound Obstet Gynecol 2004;24:211-5.[CrossRef][Web of Science][Medline]
8. Francois K, Mayer S, Harris C, Perlow JH. Association of vasa previa at delivery with a history of second-trimester placenta previa. J Reprod Med 2003;48:771-4.[Web of Science][Medline]
9. Antoine C, Young BK, Silverman F, Greco MA, Alvarez SP. Sinusoidal fetal heart rate pattern with vasa praevia in twin pregnancy. J Reprod Med 1982;27:295-300.[Web of Science][Medline]

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