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Vasa previa and placenta associated complications

Ruiter, L.

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Citation for published version (APA):Ruiter, L. (2017). Vasa previa and placenta associated complications: Diagnosis and risk assessment

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Download date: 24 May 2018

CHAPTER 1

General introduction

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GENERAL INTRODUCTION

For women, to carry out a full term pregnancy and to deliver a healthy baby depends on several factors. The development and growth of the fetus is crucial and obviously cannot be accomplished without the placenta and umbilical cord. The placenta is a highly specialized organ of the pregnancy that supports the normal growth and development of the fetus. Development of the placenta is accurately regulated to ensure exchange of nutrients and waste products between the circulatory systems of the mother and fetus.1 The umbilical cord connects the placenta and the fetus and makes transport of these nutrients and waste products between them possible. Impaired functioning of the placenta is seen in many diseases such as pregnancy induced hypertension and pre-eclampsia. These complications can result in suboptimal growth of the fetus, preterm delivery and higher rates of neonatal intensive care unit admissions.2 But also morphological anomalies of the placenta and the umbilical cord can lead to maternal morbidity and poor perinatal outcome.

This thesis on anomalies of the umbilical cord and placenta will focus on vasa previa, placenta previa, placental abruption, postpartum hemorrhage and retained placenta.

A normally developed placenta consists of the basal plate (the maternal side of the placenta) and the chorionic plate (the fetal side of the placenta) and weighs about 600 grams at delivery in the term period of pregnancy.3, 4 The umbilical cord rises from the chorionic plate and in the majority of the pregnancies the origin is in the center part of the placenta. An abnormal umbilical cord insertion implies an insertion which is towards the placental edge and can be stratified as eccentric (>2cm from the placental edge), marginal (<2cm from the placental edge) or velamentous.

Vasa previaIn velamentous cord insertion the umbilical cord inserts outside the chorionic plate directly into the fetal membranes, it is seen in approximately 0.5% of all pregnancies.5, 6 In velamentous cord insertion, fetal vessels deriving from the umbilical cord run through the fetal membranes before entering the placenta and are partially unsupported by either the Wharton’s jelly -a specialized tissue that acts as supportive and protective structure substituting for the adventitia of the umbilical vessels- or placental tissue.6, 7 Pregnancies with a velamentous cord insertion are associated with adverse perinatal outcomes such as intra-uterine fetal demise, small for gestational age neonates and preterm delivery <37 weeks of gestation.5

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1Velamentous cord insertion can result in vasa previa when the fetal vessels that run through the membranes traverse the cervical internal os. Vasa previa can be divided into two subtypes; type I is a single lobed placenta with a velamentous cord insertion covering or close to the cervix and type II is a multi-lobed placenta with connecting fetal vessels running over the cervical internal os.8 (Figure 1a and b) Compression of these vessels by the presenting part may lead to fetal heart decelerations and bradycardia on the cardiotocogram.9, 10 Theoretically in case of rupture of membranes, vasa previa can rupture simultaneously, thus potentially causing fetal blood loss with serious neonatal morbidity or neonatal death.

Figure 1a. Type I vasa previa Figure 1b. Type II vasa previa

Placenta previaWhereas the majority of the placentas are located high on the anterior or posterior wall of the uterus, placental tissue can also cover the cervix, a condition which is called placenta previa. Placenta previa is seen in 0.4-0.8% of all pregnancies and is classified according to ultrasound imaging as complete (with placental tissue completely covering the internal cervical os) or incomplete (traditionally also called partial or marginal, with placental tissue reaching to but not covering the internal cervical os).11-13 Especially a complete placenta previa is associated with emergency delivery by Cesarean section and maternal morbidity such as antepartum hemorrhage and blood transfusion, need for hysterectomy postpartum and adverse perinatal outcomes as preterm delivery, anaemia and respiratory distress syndrome.11

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Placental abruptionPlacental abruption refers to the premature dehiscence of a normally inserted placenta from the uterine wall. It is associated with significant perinatal morbidity and accounts for 12% of all perinatal deaths in the United States.14 Diagnosis of placental abruption is difficult, since the clinical presentation includes not very specific symptoms such as vaginal bleeding and abdominal pain. Early diagnosis of placental abruption can potentially be obtained by intensive surveillance and may improve the outcome of children involved in these pregnancies, by closely monitoring women who are at risk.15 Advanced maternal age, multiparity, chronic hypertension, smoking, cocaine use, previous Cesarean delivery, uterine surgery and short interpregnancy interval are reported risk factors for placental abruption.16-20

Retained placenta and postpartum hemorrhageIn addition to prenatal complications regarding the placenta, the placenta can also cause postpartum complications. In the normal situation the placenta detaches from the uterine wall spontaneously and is delivered shortly after delivery of the neonate. Although there is no universal consensus for the length of time allotted, several guidelines suggest to use 30 minutes after delivery of the neonate as the length of time before an intervention is advised.21 Interventions can involve manual or operative removal of the placenta and can potentially increase postpartum hemorrhage and infections. This is of importance, since postpartum hemorrhage is still one of the leading causes of maternal morbidity and mortality in developed and third world countries despite improvements in prevention and management.22, 23

BackgroundAt the time the research in this thesis was initiated, the literature on vasa previa was mainly restricted to case-reports, reviews and small case-series. The focus in these studies particularly lay on the outcome of vasa previa, which appeared to depend on prenatal diagnosis.8, 24, 25 Unfortunately since vasa previa is a rather rare complication, publication bias seemed to be a significant problem with mostly publication of case reports reporting adverse neonatal outcome such as fetal demise in ruptured vasa previa. Studies evaluating the prenatal diagnosis of vasa previa and its outcome objectively were not readily available. It has been hypothesized that prenatal recognition of vasa previa by ultrasound screening enables elective delivery of the fetus by Cesarean section, thus avoiding potential neonatal morbidity or fetal demise.25, 26 Different researchers and patient associations advocated to start a screening program on vasa previa for all pregnant women based on the available literature.

Placenta associated complications such as placenta previa, placental abruption and postpartum hemorrhage due to retained placenta have been studied previously to a greater

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1or lesser extent. But the consequences for women regarding future pregnancies after suffering placental abruption or severe postpartum hemorrhage due to retained placenta were not clear. Consequently, prenatal and perinatal care in women with a history of placental abruption, severe postpartum hemorrhage and/or retained placenta is not clearly defined in guidelines and therefore varies worldwide.15 In addition, for women with placenta previa several recommendations can be found regarding timing of delivery (most often a preterm elective Cesarean section) and administration of antenatal corticosteroids for fetal lung maturation, but there still is a lack of consensus.27

Objectives and outline of this thesisThe objectives of this thesis were to systematically assess the established screening criteria for the development of a screening program regarding vasa previa. We also identified factors that predict the risk of emergency delivery in women with placenta previa and we investigate the consequences of a history of placental abruption, severe postpartum hemorrhage and retained placenta for potential future pregnancies.

Part 1. Vasa previaIn the first part of this thesis we focus on vasa previa and investigate the possibilities for a potential screening strategy.

Chapter 2 What is the diagnostic accuracy of ultrasound in the prenatal diagnosis of vasa previa?

Chapter 3 What is the incidence of vasa previa and what are risk indicators for vasa previa?Chapter 4 Screening, diagnostiek en beleid bij vasa previa – concept richtlijn. Part 2. Placenta associated complicationsIn the second part of this thesis we focus on placenta previa, placental abruption and retained placenta with hemorrhage postpartum.

Chapter 5 What are risk factors for emergency delivery in women with placenta previa?Chapter 6 What is the incidence and recurrence rate of placental abruption?Chapter 7 What is the incidence and recurrence rate of severe postpartum hemorrhage

and/or retained placental tissue?

Chapter 8 General discussion and implications for further research

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REFERENCES

1. Gude NM, Roberts CT, Kalionis B, King RG. Growth and function of the normal human placenta. Thrombosis research. 2004;114(5-6):397-407.

2. Habli M, Levine RJ, Qian C, Sibai B. Neonatal outcomes in pregnancies with preeclampsia or gestational hypertension and in normotensive pregnancies that delivered at 35, 36, or 37 weeks of gestation. American journal of obstetrics and gynecology. 2007 Oct;197(4):406.e1-7.

3. Janthanaphan M, Kor-Anantakul O, Geater A. Placental weight and its ratio to birth weight in normal pregnancy at Songkhlanagarind Hospital. J Med Assoc Thai. 2006 Feb;89(2):130-7.

4. Lurie S, Feinstein M, Mamet Y. Human fetal-placental weight ratio in normal singleton near-term pregnancies. Gynecol Obstet Invest. 1999;48(3):155-7.

5. Esakoff TF, Cheng YW, Snowden JM, Tran SH, Shaffer BL, Caughey AB. Velamentous cord insertion: is it associated with adverse perinatal outcomes? The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstet. 2015 Mar;28(4):409-12.

6. Eddleman KA, Lockwood CJ, Berkowitz GS, Lapinski RH, Berkowitz RL. Clinical significance and sonographic diagnosis of velamentous umbilical cord insertion. American Journal of Perinatology. 1992 3/1992;9(2):123-6.

7. Kulkarni ML, Matadh PS, Ashok C, Pradeep N, Avinash T, Kulkarni AM. Absence of Wharton’s jelly around the umbilical arteries. Indian J Pediatr. 2007 8/2007;74(8):787-9.

8. Catanzarite V, Maida C, Thomas W, Mendoza A, Stanco L, Piacquadio KM. Prenatal sonographic diagnosis of vasa previa: ultrasound findings and obstetric outcome in ten cases. Ultrasound in Obstetrics & Gynecology. 2001 8/2001;18(2):109-15.

9. Naftolin F, Mishell DR, Jr. Vasa previa. Report of 3 cases. Obstetrics & Gynecology. 1965 10/1965;26(4):561-5.

10. Antoine C, Young BK, Silverman F, Greco MA, Alvarez SP. Sinusoidal fetal heart rate pattern with vasa previa in twin pregnancy. Journal of Reproductive Medicine. 1982 5/1982;27(5):295-300.

11. Dola CP, Garite TJ, Dowling DD, Friend D, Ahdoot D, Asrat T. Placenta previa: does its type affect pregnancy outcome? Am J Perinatol. 2003 Oct;20(7):353-60.

12. Tuzovic L. Complete versus incomplete placenta previa and obstetric outcome. Int J Gynaecol Obstet. 2006 May;93(2):110-7.

13. Vergani P, Ornaghi S, Pozzi I, Beretta P, Russo FM, Follesa I, et al. Placenta previa: distance to internal os and mode of delivery. American journal of obstetrics and gynecology. 2009 Sep;201(3):266 e1-5.

14. Ananth CV, Wilcox AJ. Placental abruption and perinatal mortality in the United States. Am J Epidemiol. 2001 Feb 15;153(4):332-7.

15. Rasmussen S, Irgens LM, Albrechtsen S, Dalaker K. Women with a history of placental abruption: when in a subsequent pregnancy should special surveillance for a recurrent placental abruption be initiated? Acta obstetricia et gynecologica Scandinavica. 2001 Aug;80(8):708-12.

16. Ananth CV, Savitz DA, Luther ER. Maternal cigarette smoking as a risk factor for placental abruption, placenta previa, and uterine bleeding in pregnancy. Am J Epidemiol. 1996 Nov 1;144(9):881-9.

17. Ananth CV, Savitz DA, Williams MA. Placental abruption and its association with hypertension and prolonged rupture of membranes: a methodologic review and meta-analysis. Obstetrics and gynecology. 1996 Aug;88(2):309-18.

18. Getahun D, Oyelese Y, Salihu HM, Ananth CV. Previous cesarean delivery and risks of placenta previa and placental abruption. Obstetrics and gynecology. 2006 Apr;107(4):771-8.

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119. Hulse GK, Milne E, English DR, Holman CD. Assessing the relationship between maternal cocaine

use and abruptio placentae. Addiction. 1997 Nov;92(11):1547-51.20. Tikkanen M, Nuutila M, Hiilesmaa V, Paavonen J, Ylikorkala O. Prepregnancy risk factors for

placental abruption. Acta obstetricia et gynecologica Scandinavica. 2006;85(1):40-4.21. Coviello EM, Grantz KL, Huang CC, Kelly TE, Landy HJ. Risk factors for retained placenta. American

journal of obstetrics and gynecology. 2015 Dec;213(6):864 e1- e11.22. World Health Organization. WHO Recommendations for the prevention and treatment of

postpartum haemorrhage. . Geneva (Switzerland); 2012.23. Mathai M, Gulmezoglu AM, Hill S. Saving womens lives: evidence-based recommendations for

the prevention of postpartum haemorrhage. Bulletin of the World Health Organization. 2007 Apr;85(4):322-3.

24. Lee W, Lee VL, Kirk JS, Sloan CT, Smith RS, Comstock CH. Vasa previa: prenatal diagnosis, natural evolution, and clinical outcome. Obstetrics & Gynecology. 2000 4/2000;95(4):572-6.

25. Smorgick N, Tovbin Y, Ushakov F, Vaknin Z, Barzilay B, Herman A, et al. Is neonatal risk from vasa previa preventable? The 20-year experience from a single medical center. Journal of Clinical Ultrasound. 2010 3/2010;38(3):118-22.

26. Seince N, Carbillon L, Perrot N, Uzan M. Various Doppler sonographic appearances and challenges in prenatal diagnosis of vasa praevia. Journal of Clinical Ultrasound. 2002 9/2002;30(7):450-4.

27. Balayla J, Wo BL, Bedard MJ. A late-preterm, early-term stratified analysis of neonatal outcomes by gestational age in placenta previa: defining the optimal timing for delivery. The journal of maternal-fetal & neonatal medicine : the official journal of the European Association of Perinatal Medicine, the Federation of Asia and Oceania Perinatal Societies, the International Society of Perinatal Obstet. 2015;28(15):1756-61.