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Diagnosis of Placental Position by Early First-Trimester Ultrasound: A Pilot Study


Objective: Conventional wisdom is that placental location cannot be identified before 8 weeks’ gestation when the placenta first becomes hyperechogenic on ultrasound. We sought to evaluate whether placental location could be reliably diagnosed between 5 and 6 weeks’ gestation. Materials and Methods: This was a retrospective analysis of prospectively acquired data. Early placental location was diagnosed by evaluation of the embryonal and yolk sac position inside the gestational sac on transvaginal ultrasound. Placental position was described as anterior, posterior, fundal, or lateral. Early and mid-pregnancy placental locations were compared and coded as being the same, having migrated to an adjacent surface, or being on an opposite surface. Results: A total of 111 patients met study criteria, providing 141 placental locations, comprising 85 singleton and reduced pregnancies and 28 dichorionic twin pregnancies. The most common placental location was anterior in both singleton and twin/triplet pregnancies. Placental location at the mid-pregnancy ultrasound was consistent with early pregnancy location in 100% of cases, with 79.5% (112/141) being on the same surface and 20.5% (29/141) having expanded onto an adjacent surface. Placental location was not associated with pregnancy outcome, although our study may have been underpowered to detect a significant difference. Conclusions: Placental location diagnosed at 5 to 6 weeks’ gestation is consistent with the location on mid-pregnancy ultrasound. Excluding the presence of an ectopic, cornual, or cesarean section scar and uterine subseptation pregnancy in early first trimester would allow a more effective tailoring of pregnancy follow-up.

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  1. Rizk B, Holliday CP, Abuzeid M. Challenges in the diagnosis and management of interstitial and cornual ectopic pregnancies. Middle East Fertil Soc Jl. 2013;18(4):235–240.

    Article  Google Scholar 

  2. Timor-Tritsch IE, Monteagudo A, Cali G, El Refaey H, Kaelin Agten A, Arslan AA. Easy sonographic differential diagnosis between intrauterine pregnancy and cesarean delivery scar pregnancy in the early first trimester. Am J Obstet Gynecol. 2016; 215(2):225 e1–227.

    Article  Google Scholar 

  3. Michaels AY, Washburn EE, Pocius KD, Benson CB, Doubilet PM, Carusi DA. Outcome of cesarean scar pregnancies diagnosed sonographically in the first trimester. J Ultrasound Med. 2015;34(4):595–599.

    Article  Google Scholar 

  4. Olive EC, Roberts CL, Nassar N, Algert CS. Test characteristics of placental location screening by transabdominal ultrasound at 18–20 weeks. Ultrasound Obstet Gynecol. 2006;28(7):944–949.

    Article  CAS  Google Scholar 

  5. Taipale P, Hiilesmaa V, Ylostalo P. Diagnosis of placenta previa by transvaginal sonographic screening at 12–16 weeks in a non- selected population. Obstet Gynecol. 1997;89(3):364–367.

    Article  CAS  Google Scholar 

  6. Jirasek JE. An Atlas of Human Prenatal Developmental Mechanics: Anatomy and Staging. London: Taylor & Francis; 2004.

    Book  Google Scholar 

  7. Applebaum M. Predicting placental location–the pattern of decid-ual blood flow in early pregnancy using the gray-scale technique. Ultrasound Obstet Gynecol. 1995;6(4):299–300.

    Article  CAS  Google Scholar 

  8. Gizzo S, Noventa M, Vitagliano A, et al. Sonographic assessment of placental location: a mere notional description or an important key to improve both pregnancy and perinatal obstetrical care?. A large cohort study. Int J Clin Exp Med. 2015;8(8):13056–13066.

    PubMed  PubMed Central  Google Scholar 

  9. Magann EF, Doherty DA, Turner K, Lanneau GS Jr., Morrison JC, Newnham JP. Second trimester placental location as a predictor of an adverse pregnancy outcome. JPerinatol. 2007;27(1): 9–14.

    Article  CAS  Google Scholar 

  10. Seow KM, Huang LW, Lin YH, Lin MY, Tsai YL, Hwang JL. Cesarean scar pregnancy: issues in management. Ultrasound Obstet Gynecol. 2004;23(3):247–253.

    Google Scholar 

  11. American College of Obstetricians, Gynecologists. ACOG Practice Bulletin No. 125: chronic hypertension in pregnancy. Obstet Gynecol. 2012;119(2 pt 1):396–407.

    Google Scholar 

  12. American College of Obstetricians, Gynecologists. ACOG Practice bulletin no. 134: fetal growth restriction. Obstet Gynecol. 2013;121(5):1122–1133.

    Article  Google Scholar 

  13. American College of Obstetricians, Gynecologists. Practice bulletins No. 139: premature rupture of membranes. Obstet Gynecol. 2013;122(4):918–930.

    Article  Google Scholar 

  14. Benirschke K, Kaufmann P. The Pathology of the Human Placenta. New York, NY: Springer-Verlag; 1990.

    Book  Google Scholar 

  15. King DL. Placental migration demonstrated by ultrasonography. A hypothesis of dynamic placentation. Radiology. 1973;109(1): 167–170.

    Article  CAS  Google Scholar 

  16. Rizos N, Doran TA, Miskin M, Benzie RJ, Ford JA. Natural history of placenta previa ascertained by diagnostic ultrasound. Am J Obstet Gynecol. 1979;133(3):287–291.

    Article  CAS  Google Scholar 

  17. Rac MW, Moschos E, Wells CE, McIntire DD, Dashe JS, Twick- ler DM. Sonographic findings of morbidly adherent placenta in the first trimester. JUltrasound Med. 2016;35(2):263–269.

    Article  Google Scholar 

  18. 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(2):79–84.

    Article  Google Scholar 

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Correspondence to Laura Detti.

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Detti, L., Gordon, J.C., Christiansen, M.E. et al. Diagnosis of Placental Position by Early First-Trimester Ultrasound: A Pilot Study. Reprod. Sci. 26, 1512–1518 (2019).

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  • early pregnancy
  • placenta
  • location
  • ultrasound