Complete placenta previa in the second trimester: clinical and sonographic factors associated with its resolution
Abstract
Objectives: This study was carried out to evaluate outcomes of pregnancies with complete placenta previa diagnosed in mid-pregnancy, and evaluate whether a history of caesarean section and placenta location effect the resolution of placenta previa.
Material and methods: A prospective observational study was conducted on patients diagnosed with complete placenta previa by ultrasound examination between 20+0 weeks and 25+6 weeks of gestation. Patients were grouped in terms of placenta location (anteriorly or posteriorly located) and presence/absence of prior caesarean section. Maternal demographics, ultrasound findings and pregnancy outcomes were subsequently compared between these groups. Statistical analysis was performed by using SPSS version 16.0.
Results: 70 patients with the above characteristics were recruited in our study. Of the 70 patients, 21 (30%) had prior caesarean section, and 41 (58.6%) had an anteriorly located placenta. Patients with prior cesarean delivery delivered earlier (36.9 ± 2.2 weeks versus 38.0 ± 1.8 weeks, P = 0.039). Furthermore, 74.3% of the placenta previa resolved by delivery. Prior caesarean section (RR 2.941, 95% CI 0.938–9.216, P 0.024) and anterior placenta (RR 3.805, 95% CI 1.126–12.855, P 0.031) were related to greater risk of persistence of placenta previa to term.
Conclusions: Prior caesarean section and anteriorly located placenta are important factors that modify the risk that previa will complicate delivery. Our findings may be useful for patient counselling and future management of the condition.
Keywords: placenta previacesarean sectionprenatal ultrasonographypregnancy outcome
References
- Kollmann M, Gaulhofer J, Lang U, et al. Placenta praevia: incidence, risk factors and outcome. J Matern Fetal Neonatal Med. 2016; 29(9): 1395–1398.
- Tuzovic L. Complete versus incomplete placenta previa and obstetric outcome. Int J Gynaecol Obstet. 2006; 93(2): 110–117.
- Wexler P, Gottesfeld KR, Wexler P, et al. Second trimester placenta previa. An apparently normal placentation. Obstet Gynecol. 1979; 54(2): 231–234.
- Becker RH, Vonk R, Mende BC, et al. The relevance of placental location at 20-23 gestational weeks for prediction of placenta previa at delivery: evaluation of 8650 cases. Ultrasound Obstet Gynecol. 2001; 17(6): 496–501.
- Dashe JS, McIntire DD, Ramus RM, et al. Persistence of placenta previa according to gestational age at ultrasound detection. Obstet Gynecol. 2002; 99(5 Pt 1): 692–697.
- Dola CP, Garite TJ, Dowling DD, et al. Placenta previa: does its type affect pregnancy outcome? Am J Perinatol. 2003; 20(7): 353–360.
- Gorodeski IG, Bahari CM. The effect of placenta previa localization upon maternal and fetal-neonatal outcome. J Perinat Med. 1987; 15(2): 169–177.
- Morgan J. Placenta praevia: report on a series of 538 cases (1938-1962). J Obstet Gynaecol Br Commonw. 1965; 72(5): 700–705.
- Crenshaw C, Jones DE, Parker RT. Placenta previa: a survey of twenty years experience with improved perinatal survival by expectant therapy and cesarean delivery. Obstet Gynecol Surv. 1973; 28(7): 461–470.
- Cotton DB, Read JA, Paul RH, et al. The conservative aggressive management of placenta previa. Am J Obstet Gynecol. 1980; 137(6): 687–695.
- Lal AK, Nyholm J, Wax J, et al. Resolution of complete placenta previa: does prior cesarean delivery matter? J Ultrasound Med. 2012; 31(4): 577–580.
- Ghourab S, Al-Jabari A. Placental migration and mode of delivery in placenta previa: transvaginal sonographic assessment during the third trimester. Ann Saudi Med. 2000; 20(5-6): 382–385.
- Osmundson SS, Wong AE, Gerber SE. Second-trimester placental location and postpartum hemorrhage. J Ultrasound Med. 2013; 32(4): 631–636.
- Naji O, Daemen A, Smith A, et al. Does the presence of a cesarean section scar influence the site of placental implantation and subsequent migration in future pregnancies: a prospective case-control study. Ultrasound Obstet Gynecol. 2012; 40(5): 557–561.
- Kurjak A, Barsić B. Changes of placental site diagnosed by repeated ultrasonic examination. Acta Obstet Gynecol Scand. 1977; 56(3): 161–165.
- Magann EF, Evans SF, Newnham JP. Placental implantation at 18 weeks and migration throughout pregnancy. South Med J. 1998; 91(11): 1025–1027.
- Townsend RR, Laing FC, Nyberg DA, et al. Technical factors responsible for "placental migration": sonographic assessment. Radiology. 1986; 160(1): 105–108.
- Blouin D, Rioux C. Routine third trimester control ultrasound examination for low-lying or marginal placentas diagnosed at mid-pregnancy: is this indicated? J Obstet Gynaecol Can. 2012; 34(5): 425–428.
- Eichelberger KY, Haeri S, Kessler DC, et al. Placenta previa in the second trimester: sonographic and clinical factors associated with its resolution. Am J Perinatol. 2011; 28(9): 735–739.
- Heller HT, Mullen KM, Gordon RW, et al. Outcomes of pregnancies with a low-lying placenta diagnosed on second-trimester sonography. J Ultrasound Med. 2014; 33(4): 691–696.
- Oppenheimer L, Holmes P, Simpson N, et al. Diagnosis of low-lying placenta: can migration in the third trimester predict outcome? Ultrasound Obstet Gynecol. 2001; 18(2): 100–102.
- Lauria MR, Smith RS, Treadwell MC, et al. The use of second-trimester transvaginal sonography to predict placenta previa. Ultrasound Obstet Gynecol. 1996; 8(5): 337–340.
- Varma TR. The implication of a low implantation of the placenta detected by ultrasonography in early pregnancy. Acta Obstet Gynecol Scand. 1981; 60(3): 265–268.
- Palacios-Jaraquemada JM. Caesarean section in cases of placenta praevia and accreta. Best Pract Res Clin Obstet Gynaecol. 2013; 27(2): 221–232.
- Cho JY, Lee YH, Moon MH, et al. Difference in migration of placenta according to the location and type of placenta previa. J Clin Ultrasound. 2008; 36(2): 79–84.
