Chiang Mai Med J 2007;46(3):107-113.

Address requests for reprints: Vorapin Gomutbutra, M.D., Obstetrics and Gynecology Department, NakornpingHospital, Chotana Rd, Maerim District, Chiang Mai 50180, Thailand.

Received 10 January 2007, and in revised form 5 May 2007.

Cases report

RUPTURED VASA PREVIA: REPORT OF FOUR CASES

Vorapin Gomutbutra, M.D.

Obstetrics and Gynecology Department, Nakornping Hospital, Chiang Mai

Abstract The author reported 4 cases of ruptured Previa with a fatal perinatal outcome oftwo dead fetus in utero, two still births and a neonatal death. No definite prenatal diagnosiscould be made in any of them. After experiencing two cases, every risk case needed aware-ness especially in unexplainable severe fetal distress after small bloody aminotic fluid.However, two more fetal deaths occurred with Ruptured Vasa Previa

Antenatal diagnosis and elective cesarean section may reduce mortality and morbidity. Thepurpose of this report was to postulate whether some special devices may soon be able todetect this abnormality in a high index of suspicious cases. Chiang Mai Medical J2007;46(3):107-113.

Keywords: Vasa Previa, fetal mortality, diagnosis

Vasa Previa is an uncommon variant ofplacental anatomy. The fetal vessels areunsupported by Wharton’s jelly of the umbili-cal cord or placental mass, and coursing withinthe membrane running between the cervix andfetal presenting part Vasa Previa occurs inapproximately 1:2,000 to 1:5,000 deliveries andis one of the rare causes of antepartal orintrapartal hemorrhage.(1,2) Vasa Previaimmediately provokes fetal distress even if itis not ruptured, and only after the vesselcompressed by the presenting part may cause50-60% of fetal mortalities.(3) Hemorrhageafter the vessels are torn following spontane-ous or artificial membrane rupture would

result in a much higher fetal mortality rate rang-ing from 75 to 100%.(4) Classically, the diag-nosis would not be certain until severe fetaldistress was detected after a small amount ofbloody amniotic fluid flowed out of the vagina.The fetal mortality is potentially preventable ifcorrected early, with diagnosis and pregnancytreatment being made before the onset oflabor or after membrane rupture.

The four cases described here were antepartum and intrapartum hemorrhage fromruptured Vasa Previa, which resulted in 100%fetal mortality. The purpose of this report wasto emphasize that although Vasa Previa mightbe rare, its frequently poor outcome would be

108 Gomutbutra V.

improved if diagnosis and proper managementcould be made before membrane rupture.

Cases reportCase 1 (P.S.)A 34 year old woman of gravida 2, Para 1

at 42 weeks of gestation by last menstrualperiod (LMP) was referred to NakornpingHospital from a district hospital in Chiang Maiprovince with fetal distress. The antennalcourse was uncomplicated. However, duringthe first stage of labor she had bloody leakageof amniotic fluid of about 200-300 cc. Thefetal heart rate was suddenly bradycardia atabout 60 beats per minute, counted by aportable ultrasound, so she was referredimmediately. An hour after membrane leak-age in the labor room at Nakornping Hospitala dead fetus in the utero was found by ultra-sound. Therefore, vagina delivery was con-ducted. A still born male fetus of 3,150 gramswith Velamentous insertion of the umbilical cord

and ruptured Vasa Previa was found and isshown in Fig. 1.

Cases 2A 41 year old woman of gravida 3 Para 2 at

32 weeks of gestation, with previous cesareansection and one abortion with curette, wasadmitted to the labor room from prematurerupture of membrane (PROM). She had beenbleeding per vagina at about 200 cc forapproximately an hour before hard. There wasno fetal movement. A dead fetus in the uterowas found by ultrasound, with severe oligohy-dramnios. Vaginal delivery with vacuumextraction was performed to shorten thesecond stage of labor. A very pale dead fetusof 1,950 grams was still born with Velamentusinsertion of the umbilical cord and rupturedVasa Previa, as shown in Fig. 2.

Case 3A 28 year old woman of gravida 2 Para 2,

Figure 1. Case 1 (PS)

Ruptured Vasa Previa 109

with a twin pregnancy in Vertex/vertex posi-tion, came to the labor room at 38 weeks ofgestation. She was admitted because ofcontinued amniotic fluid leakage half an hourbefore coming to hospital. In the labor room,she had 200 cc of more vaginal bleeding and asudden drop to less than 100 beats per minutefetal heart rate. Due to the awareness of aruptured Vasa Previa, an emergency cesareansection was performed in less than fifteenminutes to save the fetal distress. However,this was not fast enough, and two very palemale twins of 2,900 grams and 2,400 gramswere still born with a fused placenta mono-chorion, diamnion type. On carefull examina-tion, Velamentous insertion of the umbilicalcord and ruptured Vasa Previa were detected,as in Fig. 3.

Case 4A 23 year old woman of gravida 2 Para 0

in Vertex position at 39 weeks gestation had

an indication of fetal distress after vaginableeding at about 150 cc for half an hourbefore being admitted to hospital. A suspicionof ruptured Vasa Previa urged an emergencycesarean section. A pale male new born of3,800 grams, had an apgar scored of 2 at 2minutes and 2 at 5 minutes. In spite ofaggressive neonate resuscitation including anearly endotracheal tube intubation and mechani-cal ventilation as well as blood transfusion hedied only one day later. Inspection of theplacenta at the operating room revealed Vela-mentous insertion of the umbilical cord andruptured Vasa Previa, as in Fig. 4.

DiscussionBy 2005, only one case of Vasa Previa had

been found among 2,323 deliveries in Nakorn-ping Hospital. Then, 3 cases out of 2,283deliveries (1:761) were found in 2006. All ofthem were Velamentous insertion of theumbilical cord and had not been prenatally

Figure 2. Case 2 (RK)

110 Gomutbutra V.

diagnosed. It was known that the averageincidence of this abnormality was about 1%,which may increase 10 fold in twin pregnan-

cies or in vitro fertilization.(5) The incidencemay be underestimated from undiagnosed VasaPrevia because in some cases the deliveries

Figure 4. Cases 4 (PM)

Figure 3 Cases 3 (WY)

Ruptured Vasa Previa 111

were uneventful, or bleedings too small to stopspontaneously, when the injured vessel wassealed by thrombosis.(2) However, most casesof ruptured Vasa Previa lead to fetal death,since the total fetal blood volume is only 250-300 cc. Rapid loss of only 50-150 cc causesserious hypovolemic shock of the fetus. VasaPrevia is a rare condition, but lack of aware-ness or concern always causes fatal compli-cations. All, except the last case, had antena-tal care from another hospital. From theexperience of the first two dead cases, obste-tricians at Nakornping Hospital became fullyaware of Vasa Previa when small vaginalbleeding generated fetal distress. However,no fetus could be saved when prehospitalruptured Vasa Previa cases were operated onas soon as possible after admission (less thanhalf an hour). Therefore, the only effectiveway to significantly reduce this fatal conditionis to set a high index of suspicion in every preg-nancy, with risk factors of Vasa Previa. Theseare Velamentus insertion of a cord, marginalinsertion of a cord, low-lying placenta, placentaprevia, bilobed and succenturiated placenta,multiple pregnancies, pregnancies resultingfrom in vitro fertilization, palpable vessel or sus-pected amniotic band on vaginal examination.(7)

A good fetal outcome may be expected if thiscondition is diagnosed and the fetus deliveredbefore the onset of bleeding or severe birthasphyxia. Various methods have been appliedfor effective diagnosis. Introduction of serialreal time Ultrasonography has been success-fully reported.(8) There was no successfulreport of direct visualization by amnioscopy orendoscopy. Apt tests for fetal nucleated redcell sampling from vaginal blood, and theLoendersloot test, which is based on resistanceto alkali denaturation, gave poor sensitivity, andthe Olgita test was recommended for routine

tests of perinatal vaginal fluid.(9) However, thetime consumption and false negativity of suchtestings had not been acceptable in the stan-dard care of the United States of America ofmany years.(10) Ultrasound seemed to be theonly practical noninvasive method and its speci-ficity was reported to be 91%.(11) The first casein which a diagnosis used a combination oftransvaginal Ultrasonography and color flowDoppler was reported in 1990.(12) There havebeen many more reports of accurate use ofthe transvaginal color Doppler ultrasound, andits sensitivity and specificity may bring about astrategy to reduce mortality from VasaPrevia.(13-15) A recent study indicated thatprenatal detection of velamentous insertion ofthe umbilical cord had potential and it was rec-ommended for second and third trimester ab-dominal ultrasound screening in high risk preg-nancy, followed by the color Doppler.(16)

Three-dimensional ultrasound may offer anadditional imaging adjunct to two-dimensionalultrasound.(17) With lessons learned from thesefour reported cases, the author’s opinion maypostulate the following. Firstly, if possible, asecond trimester routine Ultrasound examina-tion for placenta abnormality should be done.If low insertion of placenta is found, theumbilical cord should have a closer follow upfor serial sonographic examination for theexact site of cord insertion. Secondly, all thelatest special techniques such as three dimen-sional Ultrasonography and transvaginal colorDoppler should be implemented in all cases,with multiple pregnancy or pregnancy result-ing from in vitro fertilization. If Vasa Previawas found by any means, elective cesarean at36 to 38 weeks would be the best manage-ment to save the fetal life. Most importantly,Vasa Previa must be excluded by immediateultrasound in every case of ante partum vagi-

112 Gomutbutra V.

nal hemorrhage and fetal distress. If VasaPrevia is highly suspected from severe fetaldistress after intrapartum small vaginal bleed-ing, then an immediate cesarean section shouldbe performed, even if it results in poor out-come, and the neonate’s survival chances fromVasa Previa, with aggressive resuscitation andblood transfusions, has little chance of improve.

ConclusionThe true incidence of Vasa Previa is diffi-

cult to estimate because the condition is likelyto be under reported. Since it causes high fetalmortality, pregnancy with risk factors for thiscondition should be of concerned. Any preg-nancy with ante partum or intrapartum hem-orrhage as well as fetal distress should be keptin mind. With a high index of suspicion, ante-natal diagnosis using transvaginal sonographyand color Doppler is suggested. Delivery byelective Cesarean section at 35-38 weeksgestations and aggressive neonatal resuscita-tion, may reduce fetal mortality.

References1. Quek SP, Tan KL. Vasa previa. Aust NZ J Obstet

Gynecol 1972;12:206-9.2. Kouyoumdjian A. Velamentous insertion of um-

bilical cord. Obstet Gynecol 1980;56:737-42.3. Fung TY, Lau TK. Poor perinatal outcome associ-

ated with Vasa Previa: is it preventable? A report ofthree cases and review of the literature. UltrasoundObstet Gynecol 1998;12:430-3.

4. Pent D. Vasa Previa. Am J Obstet Gynecol 1979;15151-5.

5. Benirschke K, Kaufmann P. Pathology of HumanPlacenta. New York, NY: Springer-Verlag, 2000; p.353-9.

6. Schachter M. In vitro fertilization is a risk factor forVasa Previa. Fertility and Sterility 2002;78:642-3.

7. Oyelese KO, Turner M, Lees C, Campbell S. VasaPrevia: an avoidable obstetric tragedy. ObstetGynecol Survey 1999;54:138-45.

8. Gianopoulos J, Carver T, Tomich PG, Karlman R,Gadwood K. Diagnosis of Vasa Previa with ultra-sonography. Obstet Gynecol 1987;69:488-91.

9. Odunsi K, Bullough CHW, Henzel J, Polanska A.Evaluation of chemical tests for fetal bleeding fromVasa Previa. Intern J Gynecol Obstet 1996;55:207-12.

10. Messer RH, Gomez AR, Yambo TJ. Antepartumtesting for Vasa Previa: current standard of care.1987;156:1459-62.

11. Catanzarite V, Maida C, Thomas W, Mendoza A,Stanco L, Piacquadio KM. Prenatal sonographicdiagnosis of Vasa Previa: ultrasound findings andobstetric out come in ten cases. Ultrasound ObstetGynecol 2001;18:109-15.

12. Nelson LH, Melone PJ, King M. Diagnosis of VasaPrevia with transvaginal and color flow Dopplerultrasound. Obstet Gynecol 1990;76:506-9.

13. Hata K, Hata T, Fujiwaki R, Ariyuki Y, Manabe A,Kitao M. An accurate diagnosis of vasa previa withtransvaginal color Doppler Ultrasonography. Am JObstet Gynecol 1994;171:265-7.

14. Nomiyama M, Toyota Y, Kawano H. Antenataldiagnosis of Velamentous umbilical cord insertionand Vasa Previa with color Doppler imaging. Ultra-sound Obstet Gynecol 1998;12:426-9.

15. Oyelese KO, Schwarzler P, Coates S, Sanusi A,Hamid R, Campbell S. A strategy for reducing themortality rate from Vasa Previa using transvaginalsonography with color Doppler. Ultrasound ObstetGynecol 1998;12:434-8.

16. Sepulveda W, Rojas I, Robert JA, Schnapp C,Alcalde L. Prenatal detection of velamentous inser-tion of umbilical cord: a prospective color Dopplerultrasound study. Ultrasound Obstet Gynecol 2003;21;564-9.

17. Lee W, Kirk JS, Comstock CH, Romero R. VasaPrevia: prenatal detection by three-dimensionalUltrasonography. Ultrasound Obstet Gynecol2000;16:384-7.

Ruptured Vasa Previa 113

เสนเลอดวาซาปรเวยแตก: รายงานผปวย 4 ราย

วรพนทร โกมทบตร, พ.บ.

กลมงานสตนรเวช โรงพยาบาลนครพงค จงหวดเชยงใหม

บทคดยอ รายงานผปวยหญงตงครรภ 4 ราย ในหนงรายคลอดเปนเดกแฝด ซงทงหมดปรากฏผลรายแรงถงเสยชวต ทารกสองรายเสยชวตตงแตในครรภ สองรายตายคลอด และหนงรายเสยชวตในระยะหลงคลอด ภาวะเสนเลอดวาซาปรเวยแตกแมจะพบไดนอย ประมาณ 1 ตอ 2,000 ถง 5,000ของการคลอด แตผลทเกดมกจะรนแรง ทำใหทารกเสยชวตไดมากถงรอยละ 75 ถง 100 การระลกถงภาวะนในทกรายทมความเสยง เชน การมนำครำปนเลอดไหลออกจำนวนนอย แตทารกตกอยในภาวะวกฤต

การสบคนใหไดการวนจฉยไดกอนคลอด เพอการนดหมายผาตดคลอดกอนการแตกของถงนำ การใหเลอดทารกแรกคลอด อาจชวยลดความรนแรงของภาวะแทรกซอนลงได จากการพบผปวยในรายงานนมขอเสนอแนะวาในรายทมลกษณะและเหตตองสงสยยง ควรพยายามใชเครองมอ และเทคนคพเศษในการชวยใหทราบความผดปกตของเลอดนกอนทจะแตกและเกดอนตราย เชยงใหมเวชสาร2550;46(3):107-113.คำสำคญ: วาซาปรเวย การตายปรกำเนด การวนจฉย