Management of a placenta previa is dictated by gestational age and by whether the patient is bleeding or asymptomatic. Depending on the presentation, inpatient management may be warranted, and it is advisable to have blood banking capabilities. Ensuring maternal hemodynamic stability and fetal wellbeing are the primary goals. 23
As such, there are several considerations for both the clinician and patient to optimize outcomes and minimize risks, primarily those related to iatrogenic prematurity (Figure 5)24-26:
- Though data are lacking, it is highly advisable to instruct the patient to avoid sexual activity.27
- It is highly advisable to avoid digital examinations.27
- Once a placenta previa is diagnosed at the midtrimester scan, it is recommended to rescan at 32 then 36 weeks for assessment of normalization and for documentation of persistence.5
- In case of normalization, it is important to screen for vasa previa.
- In some cases, obtaining cervical length in asymptomatic patients may aid in management decisions. It helps identify patients at higher risk for preterm birth who may hemorrhage.5 Whenever evaluating the cervix, the author recommends utilizing color Doppler to rule out a vasa previa.
- Though data are inconclusive about the association of a placenta previa with fetal growth abnormalities,9 close surveillance of fetal growth and antenatal testing as indicated may be a consideration.
- Every attempt should be made to minimize iatrogenic preterm delivery while taking all precautions in case of bleeding and the need to deliver preterm. In anticipation of a preterm delivery, administration of antenatal steroids (and short-term tocolysis if safe for 48 hours) should be prioritized primarily in case of vaginal bleeding at 24 to 34 weeks.8
- It is important to correct maternal anemia and to administer Anti-D when indicated following a Kleihauer-Betke test for proper anti-D dosing.8
- Screening the patient for a possible placenta accreta spectrum, especially in the setting of prior cesarean deliveries, while taking all the necessary steps required for intraoperative management, is paramount.8
- Consultation with the neonatology team should be arranged to have the family discuss their wishes with the neonatology team, particularly in cases of peri-viability.8
- In case of cessation of vaginal bleeding for over 48 hours and where the patient is dependable and has reliable means of transportation, outpatient management is a consideration.8
- There is no evidence to support prophylactic cerclage in patients with a placenta previa.8
- Timing of delivery is dependent on several factors although an early-term birth at 36 to 37 6/7 weeks is recommended,24,25 without the need to verify fetal lung maturity via amniocentesis,24 to optimize maternal and neonatal outcomes. 28
- There is no evidence to support the need for general versus regional anesthesia in patients with a placenta previa and that should be left to the discretion of the anesthesiology team.8
Incidence of placenta previa is on the rise and is directly related to the number of prior cesarean sections. It leads to serious maternal and neonatal morbidity and mortality. Screening all patients and properly determining placental location, using transvaginal sonography beyond 16 weeks’ gestation, is critical to avoid causing undue parental anxiety by prematurely diagnosing a placenta previa in early gestation. Ob/gyns should be aware of placental migration and normalization of a placenta previa with advancing gestation. In case of normalization, it is important to screen for vasa previa. In case of persistence, precautionary steps should be taken to safeguard both mother and baby. Vigilance, a systematic approach, and following a standardized protocol help ensure optimal outcomes.
The author reports no potential conflicts of interest with regard to this article.
- AIUM–ACR–ACOG–SMFM–SRU practice parameter for the performance of standard diagnostic obstetric ultrasound examinations. J Ultrasound Med. 2018;37:E13-E24.
- Salomon LJ, Alfirevic Z, Berghella V, Bilardo C, Hernandez‐Andrade E, Johnsen SL, et al. Practice guidelines for performance of the routine mid‐trimester fetal ultrasound scan. Ultrasound Obstet Gynecol. 2011;37:116-126.
- Kanne JP, Lalani TA, Fligner CL. The placenta revisited:radiologic–pathologic correlation. Probl Diagn Radiol. 2005;34(6):238-255.
- Taipale P, Hiilesmaa V, Ylöstalo P. Transvaginal ultrasonography at 18–23 weeks in predicting placenta previa at delivery. Ultrasound Obstet Gynecol. 1998;12:422-425.
- Jauniaux ERM, Alfirevic Z, Bhide AG, Belfort MA, Burton GJ, Collins SL, et al.. Placenta praevia and placenta accreta: diagnosis and management. Green-top Guideline No. 27a. BJOG. 2018.
- Ananth CV, Smulian JC, Vintzileos AM. The association of placenta previa with history of cesarean delivery and abortion: a meta-analysis. Am J Obstet Gynecol, 1997;177:1071-1078.
- Downes KL, Hinkle SN, Sjaarda LA, et al. Previous prelabor or intrapartum cesarean delivery and risk of placenta previa. Am J Obstet Gynecol 2015;212:669.e1-6.
- Oyelese Y, Smulian JC. Placenta previa, placenta accreta, and vasa previa. Obstet Gynecol. 2006;107(4):927-941.
- Balayla J, Desilets J, Shrem G. Placenta previa and the risk of intrauterine growth restriction (IUGR): a systematic review and meta-analysis. J Perinat Med. 2019;47(6): 577-584.
- Reddy UM, Abuhamad AZ, Levine D, Saade GR; Fetal Imaging Workshop Invited Participants. Fetal imaging: Executive summary of a joint Eunice Kennedy Shriver National Institute of Child Health and Human Development, Society for Maternal-Fetal Medicine, American Institute of Ultrasound in Medicine, American College of Obstetricians and Gynecologists, American College of Radiology, Society for Pediatric Radiology, and Society of Radiologists in Ultrasound Fetal Imaging Workshop. J Ultrasound Med. 2014;33:745-757.
- Fadl S, Moshiri M, Fligner CL, Katz DS Dighe M. Placental imaging: normal appearance with review of pathologic findings. RadioGraphics. 2017;37(3):979-998.
- Gallagher P, Fagan CJ, Bedi DG, Winsett MZ, Reyes RN. Potential placenta previa: Definition, frequency, and significance. Am J Roentgenol. 1987;149:1013-1015.
- Oppenheimer L, Holmes P, Simpson N, Dabrowski A. Diagnosis of low-lying placenta: can migration in the third trimester predict outcome? Ultrasound Obstet Gynecol. 2001;18:100-102.
- Heller HT, Mullen KM, Gordon RW, Reiss RE, Benson CB. Outcomes of pregnancies with a low‐lying placenta diagnosed on second‐trimester sonography. J Ultrasound Med. 2014;33: 691-696.
- Dashe JS, McIntire DD, Ramus RM, Santos-Ramos R, Twickler DM. Persistence of Placenta Previa According to Gestational Age at Ultrasound DetectionObstetrics & Gynecology: May 2002 - Volume 99 - Issue 5 - p 692–697.
- Wexler P, Gottesfeld KR. Second trimester placenta previa: an apparently normal placentation. Obstet Gynecol. 1977:50:706-709.
- Farine D, Fox HE, Jakobson S, Timor-Tritsch IE. Vaginal ultrasound for diagnosis of placenta previa. Am J Obstet Gynecol. 1988;159(3):566-569.
- Abuhamad AZ, Zhao Y, Abuhamad S, Sinkovskaya E, Rao R, Kanaan C, et al. Standardized six-step approach to the performance of the focused basic obstetric ultrasound examination. Am J Perinatol. 2016;33(1):90-98.
- Society of Maternal-Fetal (SMFM) Publications Committee: Sinkey RG, Odibo AO, Dashe JS.#37 Diagnosis and Management of Vasa Previa. AJOG 2015;213(5):615-619.
- Bhide A, Thilaganathan B. Recent advances in the management of placenta previa. Curr Opin Obstet Gynecol. 2004;16:447-451.
- Lee W, Lee V, Kirk JS, Sloan C, Smith R, Comstock C. Vasa previa: prenatal diagnosis, natural evolution, and clinical outcome. Obstet Gynecol. 2000;95(4):572-576.
- Klahr R, Fox NS, Zafman K, Hill MB, Connolly CT, Rebarber A. Frequency of spontaneous resolution of vasa previa with advancing gestational age. AJOG. 2019 June 21 (ePub ahead of print).
- Lockwood CJ, Russo-Stieglitz K. Placenta previa management. UpToDate. July 23, 2019.
- Spong CY, Mercer BM, D’Alton M, Kilpatrick S, Blackwell S, Saade G. Timing of indicated late-preterm and early-term birth. Obstet Gynecol. 2011;118(2 Part 1):323-333.
- American College of Obstetricians and Gynecologists. Medically indicated late-preterm and early-term deliveries. ACOG Committee opinion no. 560. Obstet Gynecol. 2013;121:908-910.
- Gyamfi-Bannerman C. Society for Maternal-Fetal Medicine (SMFM) Consult Series #44: Management of bleeding in the late preterm period. SLOG 2018;218(1):B2-B8.
- Oyelese Y, Society for Maternal-Fetal Medicine. MFM consult: Evaluation and management of low-lying placenta or placenta previa on second trimester ultrasound. Contemp Ob/Gyn. December 2010:30-3.
- Robinson B, Grobman W. Effectiveness of timing strategies for delivery of individuals with placenta previa and accreta. Obstet Gynecol. 2010; 116(4):835-842.