Monthly Archives: December 2014

Preeclampsia: Taking the Focus Off Proteinuria

Preeclampsia is a progressive multisystemic disease of pregnancy that affects the lining of the mother’s blood vessels causing high blood pressure, leaking of fluid from the blood vessels, and may also cause damage to multiple organs.

Last year, In recognition of the multisystemic nature of preeclampsia, the American College of Obstetricians and Gynecologists (ACOG) recommended that elevated blood pressure in addition to alternative systemic findings can fulfill the diagnosis of preeclampsia. Proteinuria does not need to be present to make the diagnosis of preeclampsia. Necessary interventions, such as control of blood pressure, should not be delayed because there is no protein in the urine [1,2].

Although the presence of significant* protein in the urine would indicate mulitsystemic involvement, the degree of proteinuria correlates poorly with short-term adverse outcomes and  long-term maternal renal prognosis [1-5]. There is no longer a recognized quantity of  urinary protein that would affect recommendations to deliver, thus eliminating  any degree of proteinuria as a  “severe feature” [1,2].

(*300 mg or more in a 24 hour urine timed collection  or  a protein/creatinine ratio of at least 0.3 (each measured as mg/dL) (≥ 30mg/mmol) . 1+ on dipstick may be used only if the above methods are unavailable [1,2,6])

SEVERE FEATURES OF PREECLAMPSIA AS DEFINED BY ACOG 

The following findings are severe features of preeclampsia that indicate intervention including delivery may be indicated.

  • New-onset cerebral or visual disturbances .
  • Pulmonary edema (fluid in the lungs)
  • Low platelet count (less than 100,000 /microliter)
  • Elevated liver enzymes ( transaminases ) to  twice the normal concentration,  severe persistent pain in the right upper or middle upper abdomen that does not respond to medication and is not explained by another condition or both.
  • Renal insufficiency (serum creatinine greater than1.1 mg/dL) ,or a doubling of serum creatinine in the absence of other renal  disease
  • A systolic blood pressure (SBP) greater than or equal to 160 mm Hg OR a diastolic blood pressure (DBP) greater than or equal to 110 mm Hg measured on more than one occasion at least 4 hours apart while the patient is on bedrest (unless anti hypertensive therapy is initiated before this time)

TREATMENT OF SEVERE HYPERTENSION IS RECOMMENDED EVEN IF THERE ARE NO OTHER SEVERE FEATURES OF PREECLAMPSIA PRESENT 

Stroke is a major cause of death in women with  hypertensive disorders of pregnancy. As is  the case  in women who are not pregnant, control of the systolic blood pressure appears to be at least as important as control of the diastolic blood pressure [7, 8]. A review of  international clinical practice guidelines found that most authorities recommended  treatment during pregnancy for severe hypertension defined as a  blood pressure of   greater than or equal 160 / 110 mm Hg [9,12].

The American College of Obstetricians and Gynecologists (ACOG) recommends that systolic blood pressure greater than or equal to 160 mm Hg OR diastolic blood pressure greater than or equal to 110 mm Hg that persists greater than 15 minutes should be treated within 1 hour.  ACOG recommends intravenous labetalol or hydralazine, or nifedipine orally  for the  acute treatment of severe hypertension [1,2,11].

The Society of Obstetric Medicine of Australia and New Zealand (SOMANZ) recommends antihypertensive treatment for all pregnant women with blood pressure greater than or equal to 160 mm Hg systolic OR 110 mm Hg diastolic. Severe hypertension requiring urgent treatment is defined as a systolic blood pressure greater than or equal to 170 mm Hg with or
without diastolic blood pressure greater than or equal to 110 mm Hg.  SOMANZ recommends intravenous labetalol , hydralazine , or diazoxide, or oral nifedipine for the  acute treatment of severe hypertension [13].

REFERENCES

1. Hypertension in pregnancy: executive summary. Obstet Gynecol. 2013 Nov;122(5):1122-31. doi:10.1097/01.AOG.0000437382.03963.88.PMID:24150027
2. The American College of Obstetricians and Gynecologists. Task Force on Hypertension in Pregnancy Hypertension in Pregnancy. Hypertension, Pregnancy Induced –Practice Guideline wq244 2013

3. Thangaratinam S, et. al., Estimation of proteinuria as a predictor of complications of pre-eclampsia: a systematic review. BMC Med. 2009 Mar 24;7:10. doi: 10.1186/1741-7015-7-10. PMID: 19317889

4.Payne B, et al.; PIERS Study Group. PIERS proteinuria: relationship with adverse maternal and perinatal outcome. J Obstet Gynaecol Can 2011;33:588–97.PMID: 21846448

5. Lampinen KH, Rönnback M, Groop PH, Kaaja RJ. Renal and vascular
function in women with previous preeclampsia: a comparison of lowand
high-degree proteinuria. Kidney Int 2006;70:1818–22 PMID: 17003812

6. Diagnosis, evaluation, and management of the hypertensive disorders of pregnancy: executive summary. Magee LA, Pels A, Helewa M, Rey E, von Dadelszen P; Canadian Hypertensive Disorders of Pregnancy Working Group. J Obstet Gynaecol Can. 2014 May;36(5):416-41. English, French. PMID: 24927294

7. Martin JN, Jr., et al., Stroke and severe preeclampsia and eclampsia: a paradigm shift focusing on systolic blood pressure. Obstetrics & Gynecology. 2005;105(2):246-54. PMID: 15684147

8. Lindenstrøm E, et al., Influence of systolic and diastolic blood pressure on stroke risk: a prospective observational study. Am J Epidemiol. 1995 Dec 15;142(12):1279-90. PMID: 7503048

 9. Hypertensive disorders of pregnancy: a systematic review of international clinical practice guidelines. Gillon TE, Pels A, von Dadelszen P, MacDonell K, Magee LA. PLoS One. 2014 Dec 1;9(12):e113715. doi: 10.1371/journal.pone.0113715. eCollection 2014. PMID: 25436639

10. Adverse perinatal outcomes are significantly higher in severe gestational hypertension than in mild preeclampsia. Buchbinder A, Sibai BM, Caritis S, Macpherson C, Hauth J, Lindheimer MD, Klebanoff M, Vandorsten P, Landon M, Paul R, Miodovnik M, Meis P, Thurnau G; National Institute of Child Health and Human Development Network of Maternal-Fetal Medicine Units. Am J Obstet Gynecol. 2002 Jan;186(1):66-71. PMID: 11810087

11.Emergent therapy for acute-onset, severe hypertension during pregnancy and the postpartum period. Committee Opinion No. 623. American College of Obstetricians and Gynecologists. Obstet Gynecol 2015;125:521–5.PMID: 25611642 

http://www.acog.org/Resources-And-Publications/Committee-Opinions/Committee-on-Obstetric-Practice/Emergent-Therapy-for-Acute-Onset-Severe-Hypertension-During-Pregnancy-and-the-Postpartum-Period

12. National Institute for Health and Care Excellence.Hypertension in pregnancy: The management of hypertensive disorders during pregnancyNICE clinical guideline 107
Issued: August 2010 last modified: January 2011
Avilable at: http://www.nice.org.uk/guidance/cg107. http://www.nice.org.uk/guidance/cg107/resources/guidance-hypertension-in-pregnancy-pdf Accessed 12/29/2014.

13. Society of Obstetric Medicine of Australia and New Zealand. Guideline for the Management of Hypertensive Disorders of Pregnancy 2014
Available at: https://somanz.org/documents/HTPregnancyGuidelineJuly2014.pdf
Accessed 12/29/2014.

Copyright © 2014 by Focus Information Technology. All rights reserved

Defining Oligohydramnios

This year the American College of Obstetricians and Gynecologists (ACOG) restated their support for the use of the deepest vertical pocket (DVP)  of amniotic fluid volume of 2 cm or less to diagnose oligohydramnios (too little amniotic fluid) rather than an amniotic fluid index (AFI) of 5 cm or less [1,2]. The deepest vertical pocket (a.k.a. maximum vertical pocket) method for amniotic fluid assessment is preferred because  clinical trials have shown that defining oligohydramnios as a deepest vertical pocket of less than 2 cm or less will result in fewer obstetric interventions without a change  in adverse outcomes when compared with defining oligohydramnios as an AFI of less than or equal to 5 cm [3].

Deepest Vertical Pocket of Amniotic Fluid In addition , the DVP is a simpler method to use than the AFI method. The DVP is measured as the vertical measurement , in centimeters, of the single deepest pocket of amniotic fluid with a transverse measurement of 1 cm or more wide  without fetal small parts or umbilical cord  [4] . The AFI method uses the sum of measurements obtained for the deepest vertical pocket from four quadrants of the uterus, using the same criteria otherwise.

The DVP is already used more commonly in the evaluation of twin pregnancies [5-7] . However, the AFI is used by many antenatal testing centers as part of the the modified biophysical profile (BPP) [8,9]. The modified BPP consists of the nonstress test (NST) and an amniotic fluid volume assessment using the AFI method. The modified BPP is considered normal if both the NST is reactive and the AFI is greater than 5 cm [1]. The new recommendations would require only a single maximum vertical pocket of amniotic fluid greater than 2 cm for the amniotic fluid volume assessment component of the modified BPP to  be considered normal .

The  normal the range for the deepest vertical pocket is about 2 cm  to 8 cm in singleton and twin gestations [4, 10-12] , or about one third the values for  the normal range of the AFI.  

Depth of largest visible
pocket 

 Qualitative Description

 < 1 cm
 severe oligohydramnios
> 1 and
< 2  cm
 mild oligohydramnios
 > 2  and  < 8 cm  normal
> 8
and < 12 cm
 polyhydramnios
>12 cm and <
16
 moderate polyhydramnios
> 16 cm  severe polyhydramnios

Some causes of oligohydramnios [13,14]

  • Ruptured membranes
  • Congenital abnormalities
    • Bilateral renal agenesis or cystic dyplasia
    • Obstruction of the urinary tract
    • Meckel-Gruber syndrome
    • VACTERL (vertebral, anal, cardiac, tracheo-esophageal, renal, limb) association
    • Sirenomelia
    • Sacral agenesis
  • Growth restriction (placental insufficiency)
  • Postterm pregnancy
  • Drugs
    • Angiotensin-converting enzyme inhibitors
    • Prostaglandin synthase inhibitors
  • Twin- to -twin transfusion
  • TRAP (twin reverse arterial perfusion sequence)
  • Fetal demise
  • Idiopathic

REFERENCES
1. Antepartum fetal surveillance. Practice Bulletin No. 145. American College of Obstetricians and Gynecologists. Obstet Gynecol 2014;124:182–92PMID:24945455
2. Reddy UM, et al.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 Obstet Gynecol. 2014 May;123(5):1070-82. doi: 10.1097/AOG.0000000000000245. PMID: 24785860
3. Nabhan AF, Abdelmoula YA.Amniotic fluid index versus single deepest vertical pocket as a screening test for preventing adverse pregnancy outcome. Cochrane Database Syst Rev. 2008 Jul 16;(3):CD006593. doi: 10.1002/14651858.CD006593.pub2. PMID: 18646160
4. Chamberlain PF, Manning FA, Morrison I, Harman CR, Lange IR. Ultrasound evaluation of amniotic fluid volume. I. The relationship of marginal and decreased amniotic fluid volume to perinatal outcome. Am J Obstet Gynecol 1984;150:245–9.PMID:6385713
5.Magann EF, et al. The ultrasound estimation of amniotic fluid volume in diamniotic twin pregnancies and prediction of peripartum outcomes. Am J Obstet Gynecol. 2007 Jun;196(6):570.e1-6; discussion 570.e6-8. PMID: 17547899
6.Royal College of Obstetricians and Gynaecologists .Monochorionic Twin Pregnancy, Management Green-top Guideline No. 51December 2008
https://www.rcog.org.uk/globalassets/documents/guidelines/t51managementmonochorionictwinpregnancy2008a.pdf
7. WAPM Consensus Group on Twin-to-Twin Transfusion, Baschat A, et. al. Twin-to-twin transfusion syndrome (TTTS). J Perinat Med. 2011 Mar;39(2):107-12. Epub 2010 Dec 13. PMID:21142846
8. Nageotte MP, et. al. Perinatal outcome with the modified biophysical profile. Am J Obstet Gynecol. 1994 Jun;170(6):1672-6. PMID:8203424
9.Miller DA, et. al., The modified biophysical profile: antepartum testing in the 1990s.Am J Obstet Gynecol. 1996 Mar;174(3):812-7. PMID:863364
10.Chamberlain PF, Ultrasound evaluation of amniotic fluid volume. II. The relationship of increased amniotic fluid volume to perinatal outcome. Am J Obstet Gynecol. 1984 Oct 1;150(3):250-4.PMID:6385714
11.Hill LM, et al. Polyhydramnios: ultrasonically detected prevalence and neonatal outcome.Obstet Gynecol. 1987 Jan;69(1):21-5.PMID:3540761
12. Magann EF,et al The ultrasound estimation of amniotic fluid volume in diamniotic twin pregnancies and prediction of peripartum outcomes. Am J Obstet Gynecol. 2007;196(6):570.PMID:17547899
13. Peipert JF, Donnenfeld AE, Oligohydramnios: a review.Obstet Gynecol Surv. 1991 Jun;46(6):325-39. PMID:2067755
14. McCurdy CM Jr, Seeds JW. Oligohydramnios: problems and treatment. Semin Perinatol. 1993 Jun;17(3):183-96. PMID:7690990

Copyright © 2014 by Focus Information Technology. All rights reserved

The FDA is concerned about over-the-counter sale of fetal ultrasound heartbeat monitors

The FDA issues consumer update regarding  over-the-counter sale of prescription fetal ultrasound heartbeat monitors (also called doptones).

“When the product is purchased over the counter and used without consultation with a health care professional taking care of the pregnant woman, there is no oversight of how the device is used. Also, there is little or no medical benefit expected from the exposure,” Vaezy says. “Furthermore, the number of sessions or the length of a session in scanning a fetus is uncontrolled, and that increases the potential for harm to the fetus and eventually the mother.”

See more at:

 

http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm095508.htm?source=govdelivery&utm_medium=email&utm_source=govdelivery

Placenta Accreta

An abnormally adherent placenta occurs when a defect in the endometrial lining that lies under the placenta ( the decidua basalis) allows the placenta to grow to varying depths. beyond the lining of the uterus (endometrium) into or through the myometrium (wall of the uterus) and sometimes into the adjacent bladder and intestines.  At delivery the placenta fails to separate from the uterine wall. Manual attempts to remove the placenta may cause profuse hemorrhage. The condition is collectively referred to  as “placenta accreta”. 

The three types of abnormally adherent placenta are defined according to the depth of invasion by the placenta into the myometrium. [1]

  • Placenta accreta: The placenta grows superficially into the myometrium (muscular wall of the uterus). This is the most common form of an abnormally adherent placenta and occurs in 75% of cases.
  • Placenta increta: The placenta grows into the myometrium . This occurs in 18% of cases
  • Placenta percreta:. The placenta grows completely through the uterus and may invade surrounding structures such as the bladder.and bowel. Fortunately, this is the least common form and occurs in about 7% of cases

LifeArt Image copyright 2007 .Modified by Focus I.T.2014

RISK FACTORS

The most important risk factor for the development of placenta accreta appears to be placenta previa. Patients presenting with a placenta previa and an unscarred uterus have a 5% risk of clinical placenta accreta. The incidence of placenta accreta increases to 24% in women with a placenta previa and one previous cesarean section . The risk continues to increase with each additional cesarean section up to 67% in women with a placenta previa and four or more cesarean sections [4].

Placenta Previa with Prior Uterine Incisions:  Effect on Incidence of Placenta Accreta

Number of Prior Uterine Incisions
 Percent with Placenta Accreta
0
5
1
24
2
47
3
40
4
67

Clark SL, Koonings PP, Phelan JP. Placenta previa/accreta and prior cesarean section. Obstet Gynecol 1985 Jul;66(1):89-92

Other risk factors that have been associated with the development of placenta  accreta include [6]:

  • A history of myomectomy 
  • Asherman syndrome 
  • Previous uterine thermal ablation ,
  • Uterine artery embolization 
  • Maternal age greater than 35 years old,
  • Second-trimester serum levels of AFP and free beta-hCG greater than 2.5 multiples of the median 

EVALUATION

Placenta accreta should be suspected in all women with placenta previa or when the placental location overlies a previous uterine scar.

Ultrasound [2]

  • “Grayscale ultrasonography is sensitive (77–87%) and specific (96–98%) for the diagnosis of placenta accreta The presence and increasing number of lacunae within the placenta at 15–20 weeks of gestation have been shown to be the most predictive ultrasonographic signs of placenta accreta”.
  • Additional findings on grayscale ultrasonography that suggest placenta accreta is present include [7]:
    ● abnormal placental lacunae.
    ● thinning or disruption of the hyperechoic serosa–bladder interface
    ● presence of focal exophytic masses invading the urinary bladder
    ● loss of or irregular retroplacental sonolucent zone
  • MRI may be helpful “When there are ambiguous ultrasound findings or a suspicion of a posterior placenta accreta, with or without placenta previa, ultrasonography may be insufficient.”

COUNSELING [2, 7]

  •  All women with placenta previa and their partners should be counseled regarding timing of delivery, the potential need for hysterectomy, blood transfusion cell-salvage, or intervention radiology
  • Women suspected of having placenta accreta , in addition to the above, should also be counseled about leaving the placenta in place, and possible maternal death
  • Concerns, queries or refusals of treatment should be addressed and documented clearly.
  • Patients suspected of having a placenta percreta should have consultation with a Gynecologic oncologist or other surgeon experienced in the resection of invasive neoplasms prior to delivery. Consultation for suspected placenta accreta or increta may also be warranted

MANAGEMENT

The average blood loss at delivery in women with placenta accreta is 3,000–5,000 mL . Many women will require more than 10 units of packed red blood cells. Mortality has been reported to be as high as 7%.  As stated by The American College of Obstetricians and Gynecologists (ACOG)  “Placenta accreta is a potentially life-threatening obstetric condition that requires a multidisciplinary approach to management.”[2]   [2]

Timing of Delivery [8, 2]

  • The Royal College of Obstetricians and Gynaecologists (RCOG) recommends ” Individual characteristics should be considered, but with the planning needed for the
    especially high-risk cases suspected of having placenta accreta, planned delivery at around 36–37 weeks of gestation (with corticosteroid cover [15]) is a reasonable compromise” [7]
  • ACOG recommends delivery at 34 0/7–35 6/7 weeks of gestation . “The timing of delivery should be individualized, depending on patient circumstances. Combined maternal and neonatal outcome is optimized in stable patients with a planned delivery at 34 weeks of gestation without amniocentesis.”
  •  Patients with vaginal bleeding, contractions , or premature rupture of membranes may need to be delivered at 34 weeks or sooner [9].
  • If there will be insufficient blood bank supply or inadequate availability of subspecialty and support personnel at the time of delivery then transfer of patient care to a center where such services are available is recommended.

Delivery [2,10]:

    •  “Current evidence is insufficient to make a firm recommendation on the use of balloon catheter occlusion or embolization to reduce blood loss and improve surgical outcome.”[2].
    • Preoperative cystoscopy with placement of ureteral stents may help prevent inadvertent urinary tract injury in patients who have extensive intrauterine adhesions.
    •  If accreta is highly likely a three-way Foley catheter should be placed in the bladder through the urethra to allow irrigation, drainage, and distension of the bladder, as necessary, during dissection
    •  It is reasonable to await spontaneous placental separation to confirm placenta accreta clinically.
    • “Generally, the recommended management of suspected placenta accreta is planned preterm cesarean hysterectomy with the placenta left in situ because removal of the placenta is associated with significant hemorrhagic morbidity. However, surgical management of placenta accreta may be individualized.” [2]

For example, the presence of a small focal placenta accreta would allow for more conservative management.[14]

  • Medical management should only be considered when the patient has a strong desire to preserve her fertility, is hemodynamically stable, and is willing to accept the risks (infection and later hysterectomy) involved in this conservative approach.[2]
  •  Patients wishing to have medical management of placenta accreta should be managed at a tertiary care center.

Preoperative Checklist :

  • Patient information , multidisciplinary checklist, and consents should be identified and verified
  • Persons to be involved in the patient’s care should be informed of the patient’s admission where appropriate.
    • Anesthesiologist
    • Main OR supervisor.
    • Neonatologists
    • Intensive care specialist
    • Hospital House supervisor
    • Maternal Child Services Director or Women’s Services Clinical Supervisor
  • The involved consultants (such as gynconcologist, urologist, or general surgeon)  should be on site and available, during the planned surgery. The blood bank and blood bank supervisor should be placed on alert for a potential massive hemorrhage.
    • Massive Transfusion Policy should be activated, and institutionally established massive transfusion protocols should be followed
    • Where available, cell salvage should be considered and if the woman refuses donor blood it is recommended that she be transferred to a unit with a cell saver.

Example of Multidisciplinary Checklist for the Management of Suspected Placenta Accreta [12,13]

Name                                                                      DOB
Estimated due date:                                           Confirmed by
Diagnosis                         Accreta                 Increta               Percreta
Ultrasound findings:Placenta location Interruption of bladder uterine interface   Placenta protrudes into bladderOther:
MRI findings:
Previous surgery
Desires future fertility?            Yes          No
Accepts blood ?                       Yes          No
Date and results                Blood type                    Blood antibody screenCBC                                  PT                             PTT
Has patient received a blood transfusion? If yes give detailsYes             No
Has patient received antenatal steroids ? If yes , give dates of treatment.Yes                      No
Date of planned surgery                        Gestational age on date of  surgery
To be performed day of surgery 4 units packed red blood cells on hold  Yes   No
Hysterectomy tray present ?                Yes   No
Cystoscopy tray present ?                            Yes    No    Not applicable
Primary OBGYN                 Contact informationGynOncologist                 Contact informationOther                              Contact information                       

REFERENCES:
1. Miller DA, Chollet JA, Goodwin TM. Clinical risk factors for placenta previa-placenta accreta. American Journal of Obstetrics and Gynecology. 1997;177(1):210–214.
2. Placenta accreta. Committee Opinion No. 529. American College of Obstetricians and Gynecologists. Obstet Gynecol 2012;120:207–11. PMID: 22914422 http://www.acog.org/Resources_And_Publications/Committee_Opinions/Committee_on_Obstetric_Practice/Placenta_Accreta
3. Bowman ZS, et. al., Risk Factors for Placenta Accreta: A Large Prospective Cohort. Am J Perinatol. 2014 Oct;31(9):799-804. Epub 2013 Dec 12. PMID: 24338130
4. Clark SL, Koonings PP, Phelan JP. Placenta previa/accreta and prior cesarean section. Obstet Gynecol 1985 Jul;66(1):89-92
5 Ballas J, et . al., Identifying sonographic markers for placenta accreta in the first trimester. J Ultrasound Med. 2012 Nov;31(11):1835-41. PMID: 23091257
6 Hung TH, et. al., Risk factors for placenta accreta. Obstet Gynecol. 1999 Apr;93(4):545-50. PMID: 10214831
7. Royal College of Obstetricians and Gynaecologists . Green-top Guideline No. 27. Placenta praevia, placenta praevia accreta and vasa praevia: diagnosis and management.
London. January 2011 https://www.rcog.org.uk/globalassets/documents/guidelines/gtg27placentapraeviajanuary2011.pdf.
8. Medically indicated late-preterm and early-term deliveries. Committee Opinion No. 560. American College of Obstetricians and Gynecologists. Obstet Gynecol 2013;121:908–10. PMID:23635709
9 Bowman ZS, et al., Risk factors for unscheduled delivery in patients with placenta accreta.Am J Obstet Gynecol. 2014 Mar;210(3):241.e1-6. doi: 10.1016/j.ajog.2013.09.044. Epub 2013 Oct 2. PMID: 24096181
10. Chantraine F, et. al., Individual decisions in placenta increta and percreta: a case series.J Perinat Med. 2012 Jan 23;40(3):265-70. doi: 10.1515/jpm-2011-0156.PMID:22505505
11. Fitzpatrick KE, et. al., The management and outcomes of placenta accreta, increta, and percreta in the UK: a population-based descriptive study. BJOG. 2014 Jan;121(1):62-70; discussion 70-1. PMID:23924326
12. Placenta accreta. Publications Committee, Society for Maternal-Fetal Medicine, Belfort MA. Am J Obstet Gynecol. 2010 Nov;203(5):430-9. PMID: 21055510
13. El-Messidi A, et. al. A multidisciplinary checklist for management of suspected placenta accreta. J Obstet Gynaecol Can. 2012 Apr;34(4):320-4. PMID: 22472330
14. Hull AD and Resnick R. Placenta Previa, Placenta Accreta, Abruptio Placenta, and Vasa Previa. In: Creasy RK, Resnik R, Iams JD, eds. Creasy and Resnik’s Maternal-Fetal Medicine: Principles and Practice. 7th ed. Philadelphia, Pa.: Saunders/Elsevier; 2014:736
15. Royal College of Obstetricians and Gynaecologists. Green–top Guideline No.7: Antenatal corticosteroids to reduce neonatal morbidity and mortality. London: RCOG; 2010

Copyright © 2014 by Focus Information Technology. All rights reserved