Low-lying placenta
Citation, DOI, disclosures and article data
At the time the article was created Yuranga Weerakkody had no recorded disclosures.
View Yuranga Weerakkody's current disclosuresAt the time the article was last revised Calum Worsley had no financial relationships to ineligible companies to disclose.
View Calum Worsley's current disclosures- Low lying placental position
- Potential placenta praevia
- Potential placenta previa
Low-lying placenta occurs when the placenta extends into the lower uterine segment and its edge lies close to the internal os of the cervix, without covering it.
On this page:
Usage
The term should be used when the edge of the placenta is less than 2 cm from the internal os of the cervix, in pregnancies of greater than 16 weeks gestation 1,2. A placental edge greater than 2 cm from the os is labeled normal, and a placenta covering the os is placenta previa.
Epidemiology
The estimated prevalence may be as high as 10-30% of all pregnancies 3,7. The majority of placentas classified as low-lying in early pregnancy (12-14 weeks) reach a normal position on subsequent scanning later during the pregnancy due to placental trophotropism.
Radiographic features
Transvaginal ultrasound is more accurate for evaluation of a low-lying placenta than transabdominal ultrasound, and is safe 1,8.
Natural course
A low-lying placenta detected on ultrasound in the second trimester typically resolves by the mid-third trimester. Rarely (in around 1.6% cases) it can persist to term or near term 9.
Differential diagnosis
Situations that may mimic a low lying placenta on a trans-abdominal scan includes
focal myometrial contraction(s) stretching the lower uterine segment
overdistended bladder stretching the lower uterine segment
marginal placenta previa: especially if the placenta is posterior
References
- 1. Reddy U, Abuhamad A, Levine D, Saade G, Saade G. 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(5):745-57. doi:10.7863/ultra.33.5.745 - Pubmed
- 2. Jauniaux E, Alfirevic Z, Bhide A et al. Placenta Praevia and Placenta Accreta: Diagnosis and Management. BJOG. 2018;126(1):e1-e48. doi:10.1111/1471-0528.15306 - Pubmed
- 3. V. Padubidri, Ela Anand. Textbook of Obstetrics. (2006) ISBN: 9788172252236 - Google Books
- 4. Gillieson M, Winer-Muram H, Muram D. Low-Lying Placenta. Radiology. 1982;144(3):577-80. doi:10.1148/radiology.144.3.7100476 - Pubmed
- 5. Fadl S, Moshiri M, Fligner C, Katz D, Dighe M. Placental Imaging: Normal Appearance with Review of Pathologic Findings. Radiographics. 2017;37(3):979-98. doi:10.1148/rg.2017160155 - Pubmed
- 7. Chama CM, Wanonyi IK, Usman JD. From low-lying implantation to placenta praevia: a longitudinal ultrasonic assessment. J Obstet Gynaecol. 2004;24 (5): 516-8. doi:10.1080/01443610410001722545 - Pubmed citation
- 8. Lauria MR, Smith RS, Treadwell MC, Comstock CH, Kirk JS, Lee W, Bottoms SF. The use of second-trimester transvaginal sonography to predict placenta previa. Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology. 8 (5): 337-40. doi:10.1046/j.1469-0705.1996.08050337.x - Pubmed
- 9. Heller HT, Mullen KM, Gordon RW, Reiss RE, Benson CB. Outcomes of pregnancies with a low-lying placenta diagnosed on second-trimester sonography. (2014) Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine. 33 (4): 691-6. doi:10.7863/ultra.33.4.691 - Pubmed
Incoming Links
Related articles: Pathology: Genitourinary
- obstetrics
-
first trimester
- ultrasound findings in early pregnancy
- embryo/fetus
- beta-hCG levels
- confirming intrauterine gestation
- pregnancy of unknown location (PUL)
- first trimester vaginal bleeding
- early structural scan
- aneuploidy testing
-
second trimester
- fetal biometry
- amniotic fluid volume
- fetal morphology assessment
- soft markers
- amnioreduction
- Doppler ultrasound
- nuchal translucency
- 11-13 weeks antenatal scan
- chorionic villus sampling (CVS) and amniocentesis
- other
- placenta
- placental anatomy
- placental developmental abnormalities
- placenta previa
- spectrum of abnormal placental villous adherence
- abnormalities of cord insertion
- abruptio placentae
- placental pathology
- vascular pathologies of placenta
- placental infections
- placental masses
- molar pregnancy
- twin placenta
- miscellaneous
-
first trimester
- gynecology
- acute pelvic pain
- chronic pelvic pain
- uterus
- ovaries
- ovarian follicle
- ovarian torsion
- pelvic inflammatory disease
- ovarian cysts and masses
- paraovarian cyst
- polycystic ovaries
- ovarian hyperstimulation syndrome
- post-hysterectomy ovary
- cervix
- fallopian tube
- other
- male genital tract
- prostate gland
- transrectal ultrasound
- prostate tumors
- infections of the prostate
-
prostatitis
- acute bacterial prostatitis
-
chronic prostatitis
- chronic bacterial prostatitis
- chronic prostatitis and chronic pelvic pain syndrome (CPPS)
- asymptomatic inflammatory prostatitis
- granulomatous prostatitis
- emphysematous prostatitis
- prostatic abscess
-
prostatitis
- benign prostatic hypertrophy
- cystic lesions of the prostate
- prostatic calcification
- prostatic infarction
- testes
-
unilateral testicular lesion
- testicular torsion
- orchitis
- testicular trauma
-
germ cell tumors of the testis
- testicular seminoma
-
non seminomatous germ cell tumors
- mixed germ cell tumor
- yolk sac tumor (endodermal sinus tumor)
- embryonal cell carcinoma
- choriocarcinoma
- testicular teratoma
- testicular epidermoid (teratoma with ectodermal elements only)
- burned out testis tumor
- sex cord / stromal tumors of the testis
- testicular cyst
- testicular lymphoma
- bilateral testicular lesion
- paratesticular lesions
- epididymis
- other
- polyorchidism
- cryptorchidism
- tubular ectasia of the rete testis
- cystadenoma of the rete testis
- testicular sarcoidosis
- testicular tuberculosis
- spermatic cord
- fibrous pseudotumor of the scrotum
- scrotal leiomyosarcoma
- testicular adrenal rest tumors (TARTs)
- tunica vaginalis testis mesothelioma
- splenogonadal fusion
- testicular vasculitis
- abnormal testicular Doppler flow (differential)
-
unilateral testicular lesion
- penis
- prostate gland
- KUB
- kidneys
- normal renal anatomy
- hydronephrosis
- urolithiasis
- renal masses
- renal cystic disease
- renal infection
- vascular
- trauma
- ureter
- normal ureter anatomy
- ureteral stricture
- ureteral dilatation
- ureteral anomalies
- ureteral tumors
- ureteral trauma
- other
- bladder
- kidneys
Unable to process the form. Check for errors and try again.