Influence of placental position on obstetric morbidity in placenta previa
Keywords:
Placenta previa, Caesarean hysterectomy, Placenta accreta, Placental locationAbstract
Background: In placenta previa, the placenta occupies lower uterine segment and is likely to separate during pregnancy, resulting in significant maternal and perinatal morbidity and mortality. It has been well studied as the degree of placenta previa increases, the risk of bleeding also increases. However, there are few studies regarding configuration of placenta in relation to uterine wall (anterior, posterior or lateral) and associated complications. The primary purpose of this retrospective cohort study is to examine the whether the location of placenta in relation to lower uterine segment during caesarean delivery influences development of bleeding complications necessitating various surgical interventions. The secondary objective was to study various factors such as preterm delivery, fetal growth restriction, perinatal deaths and postpartum haemorrhage in relation to location of placenta.
Methods: We conducted a retrospective study of 89 patients with placenta previa with ultrasonographically mapped placenta over a period of 5 years. The subjects were further categorized into anterior, posterior and lateral group depending upon location of placenta in relation to uterine wall. Differences between age, parity, history of previous caesarean delivery, antepartum haemorrhage, preterm deliveries, foetal growth restriction, perinatal deaths, operative complications and surgical interventions, placenta accreta and postpartum haemorrhage were studied and also were compared to traditional classification of placenta previa in relation to internal cervical ostium. The statistical analysis of the data was performed according to Pearson Chi-square test, one way ANOVA test using SPSS Software.
Results: The overall incidence of placenta previa was 1.01%. Placental location was anterior in 23 women (25.8%), posterior in 49 women ((55%) and lateral in 17 (19.1%). No significant differences were found in these groups regarding age, gestational age at delivery, parity, previous history of caesarean delivery, incidence of antepartum and postpartum haemorrhage. Need for surgical interventions such as uterine artery ligation, internal iliac artery plication, caesarean hysterectomy was not specific any type of placenta previa. 39.1% of anterior, 40% of posterior and 35.2% of lateral placenta previa received blood component therapy and this variation was not statistically significant. The overall perinatal mortality was 45/1000 live births and mortality rate did not vary significantly in any of the groups.
Conclusions: It is difficult to assign a maternal or perinatal morbidity risk to a particular type of placental location. The need for specialized surgical intervention such as uterine / internal iliac artery ligation, peripartum hysterectomy can arise irrespective of placental location, whether underneath the surgical incision (anterior), proximity to main uterine trunks (lateral) or encountered after the delivery of the baby (posterior). Pregnancies complicated by placenta previa must be delivered in the hospitals having expertise of senior and skilled surgeons and well equipped blood bank and good neonatal intensive care unit.
References
Dola CP, Garite TJ, Dowling DD, Friend D, Ahdoot D, Asrat T. Placenta previa: does its type affect pregnancy outcome? Am J Perinatol. 2003;20:353-60.
Bhide A, Prefumo F, Moore J, Hollis B, Thilaganathan B. Placental edge to internal os distance in the late third trimester and mode of delivery in placenta praevia. BJOG. 2003;110:860-4.
Bhat SM, HamdiI M, Bhat SK. Placenta previa in a referral hospital in Oman. Saud Med J. 2004;25:728-31.
Tuzovic L. Complete versus incomplete placenta previa and obstetric outcome. Int J Gynaecol Obstet. 2006;93:110-7.
Atsuko Sekiguchi, Akihito Nakai, Ikuno Kawabata, Masako Hayashi, Toshiyuki Takeshita. Type and location of placenta previa affect preterm delivery risk related to antepartum hemorrhage. Int J Med Sci. 2013;10:1683-8.
Cho JY, Lee YH, Moon MH, Lee JH. Difference in migration of placenta according to the location and type of placenta previa. J Clin Ultrasound. 2008;36:79-84.
Jang DG, We JS, Shin JU, Choi YJ, Ko HS, Park IY, Shin JC. Maternal outcomes according to placental position in placental previa. Int J Med Sci. 2011;8:439-44.
Zlatnik MG, Cheng YW, Norton ME, Thiet MP, Caughey AB. Placenta previa and the risk of preterm delivery. J Matern Fetal Neonatal Med. 2007;20:719-23.
Ozumba BC, Ezegwui HU. Blood transfusion and caesarean section in a developing country. J Obstet Gynaecol. 2006;26:746-8.
Rumina T, Shazia S, Uzma N. Factors related to blood transfusion in placental previa. J Surg Pak (Int). 2012;17:121-5.
Grgic O, Matijevic R, Vasilj O. Placental site does not change background uterine electromyographic activity in the middle trimester of pregnancy. Eur J Obstet Gynaecol Reprod Biol. 2006;127:209-12.
Hasegawa J, Matsuoka R, Ichizuka K, Mimura T, Sekizawa A, Farina A, Okai T.. Predisposing factors for massive hemorrhage during cesarean section in patients with placenta previa. Ultrasound Obstet Gynaecol. 2009;34:80-4.
Tuzovic L. Complete versus incomplete placenta previa and obstetric outcome. Int J Gynaecol Obstet. 2006;93:110-7.
Lorie MH, Anthony OO, George AM, James PC, Allison GC. Effect of placenta previa on foetal growth. Am J Obstet Gynaecol. 2010;203:330-9.
Lucy EG, Jessica LI, Vladimir BN, Frisbaek YR, Sonya AR, Joshua AC, Errol RN. Intrauterine growth restriction and placental location. J Ultrasound Med. 2007;26:1481-9.
Ahmed Bahar, Abdullah Abusham, Mamodoh Eskandar, Adekkunle Sobande, Mohamed Alsunaidi. Risk factors and pregnancy outcome in different types of placenta previa. J Obstet Gynaecol Can. 2009;31(2):126-31.
Ananth CV, Smulian JC, Vintzileos AM. The effect of placenta previa on neonatal mortality: a population based study in the United States, 1989 through 1997. Am J Obstet Gynaecol. 2003;188:1305-9.
