今日の臨床サポート

前置胎盤

著者: 近藤英治 京都大学 器官外科学 婦人科学産科学

監修: 金山尚裕 静岡医療科学専門大学校

著者校正/監修レビュー済:2020/12/03
参考ガイドライン:
  1. 日本産科婦人科学会/日本産婦人科医会:産婦人科診療ガイドライン産科編2020
患者向け説明資料

概要・推奨   

  1. 前置胎盤は夜間・休日でも大量出血や早産児の対応が可能な施設での管理が望ましい。自施設では対応困難」と判断した場合は妊娠32週末までに他院受診が完了するよう紹介する(推奨度1)。
  1. 予定帝王切開は手術中に輸血(自己血あるいは同種血)ができる体制を整えて行う(推奨度1)
  1. 癒着胎盤の評価を行い、必要時には癒着胎盤に備えた準備を行う(推奨度2)
薬剤監修について:
オーダー内の薬剤用量は日本医科大学付属病院 薬剤部 部長 伊勢雄也 以下、林太祐、渡邉裕次、井ノ口岳洋、梅田将光による疑義照会のプロセスを実施、疑義照会の対象については著者の方による再確認を実施しております。
※薬剤中分類、用法、同効薬、診療報酬は、エルゼビアが独自に作成した薬剤情報であり、
著者により作成された情報ではありません。
尚、用法は添付文書より、同効薬は、薬剤師監修のもとで作成しております。
※薬剤情報の(適外/適内/⽤量内/⽤量外/㊜)等の表記は、エルゼビアジャパン編集部によって記載日時にレセプトチェックソフトなどで確認し作成しております。ただし、これらの記載は、実際の保険適用の査定において保険適用及び保険適用外と判断されることを保証するものではありません。また、検査薬、輸液、血液製剤、全身麻酔薬、抗癌剤等の薬剤は保険適用の記載の一部を割愛させていただいています。
(詳細はこちらを参照)
著者のCOI(Conflicts of Interest)開示:
近藤英治 : 奨学(奨励)寄付など(東亜薬品工業株式会社)[2021年]
監修:金山尚裕 : 特に申告事項無し[2021年]

改訂のポイント:
  1. 産婦人科診療ガイドライン産科編2017では、帝王切開の日程は妊娠37週末までに設定することが推奨されていた。しかし、警告出血や頸管長短縮を認めず、内子宮口付近の胎盤厚が薄い場合は、突然の大量出血による緊急帝王切開のリスクは低く、児の未熟性とのバランスを考慮し、産婦人科診療ガイドライン産科編2020では帝王切開を妊娠38週末までに計画することも許容されることとなった。

病態・疫学・診察

疾患情報(疫学・病態)  
  1. 前置胎盤は、胎盤が内子宮口の全部または一部を覆う状態をいう。全妊娠の0.3~0.5%に合併する。
  1. 胎盤が内子宮口を覆う程度により全前置胎盤、部分前置胎盤、辺縁前置胎盤に分類される。
  1. 妊娠初期に認めた前置胎盤の約9割は最終的には前置胎盤でなくなる[1]
  1. 前置胎盤は、受精卵が正常の着床部位よりも下部の子宮壁に着床するために起こると考えられており、その危険因子には帝王切開術の既往、子宮内容除去術や子宮筋腫核出術など子宮の手術既往、多産、高齢、多胎、喫煙、前置胎盤の既往などがある[2]
  1. 多量性器出血を来し早期娩出が必要となることがあり、平均分娩週数は 34~35 週である。
  1. 前置胎盤単胎妊娠の場合、周産期死亡率が最も低いのは妊娠37週台での帝王切開である[3]
  1. 帝王切開時に大量出血を来すことがあり、子宮摘出が3.5~5.3%に必要であったとの報告もある[4][5]
  1. 母体死亡を0.03%に合併する[6]
  1. 癒着胎盤の危険因子である[7]
  1. 癒着胎盤のオッズ比は、帝王切開手術の既往回数が増えるにつれ8.6(1回)、17.4(2回)、55.9(3回以上)と飛躍的に上昇する[7]
問診・診察のポイント  
問診:
  1. 胎動の有無を確認する。

これより先の閲覧には個人契約のトライアルまたはお申込みが必要です。

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文献 

著者: Jodi S Dashe, Donald D McIntire, Ronald M Ramus, Rigoberto Santos-Ramos, Diane M Twickler
雑誌名: Obstet Gynecol. 2002 May;99(5 Pt 1):692-7.
Abstract/Text OBJECTIVE: To evaluate gestational age at ultrasound detection of placenta previa as a predictor of previa persistence until delivery, and to estimate the effects of previa type, parity, and prior cesarean delivery on previa persistence.
METHODS: This was a retrospective cohort study of pregnancies with placenta previa detected during transabdominal or endovaginal ultrasound examination. Previa was categorized as complete if the placenta completely covered the internal cervical os or incomplete if the inferior placental edge partially covered or reached the margin of the os. Gestational age was grouped into 4-week intervals from 15 to 36 weeks. The outcome was cesarean delivery for persistent previa.
RESULTS: Previa was detected during 940 ultrasound examinations in 714 pregnancies. Of those with placenta previa at 15-19 weeks, 20-23 weeks, 24-27 weeks, 28-31 weeks, and 32-35 weeks, previa persisted until delivery in 12%, 34%, 49%, 62%, and 73%, respectively. At each interval, complete previa was more likely to persist than incomplete previa, all P <.001. Prior cesarean delivery was an independent risk factor for persistent previa among women diagnosed with previa in the second trimester, P <.05. However, parity was not an independent risk factor for persistence at any gestational age interval after adjusting for prior cesarean delivery.
CONCLUSION: Gestational age at ultrasound detection of placenta previa may be used to predict likelihood of previa persistence. After midpregnancy, risk of persistence appears to be higher than previously reported. Type of placentation and prior cesarean delivery are important factors that modify the risk that previa will complicate delivery.

PMID 11978274  Obstet Gynecol. 2002 May;99(5 Pt 1):692-7.
著者: Yinka Oyelese, John C Smulian
雑誌名: Obstet Gynecol. 2006 Apr;107(4):927-41. doi: 10.1097/01.AOG.0000207559.15715.98.
Abstract/Text Placenta previa, placenta accreta, and vasa previa are important causes of bleeding in the second half of pregnancy and in labor. Risk factors for placenta previa include prior cesarean delivery, pregnancy termination, intrauterine surgery, smoking, multifetal gestation, increasing parity, and maternal age. The diagnostic modality of choice for placenta previa is transvaginal ultrasonography, and women with a complete placenta previa should be delivered by cesarean. Small studies suggest that, when the placenta to cervical os distance is greater than 2 cm, women may safely have a vaginal delivery. Regional anesthesia for cesarean delivery in women with placenta previa is safe. Delivery should take place at an institution with adequate blood banking facilities. The incidence of placenta accreta is rising, primarily because of the rise in cesarean delivery rates. This condition can be associated with massive blood loss at delivery. Prenatal diagnosis by imaging, followed by planning of peripartum management by a multidisciplinary team, may help reduce morbidity and mortality. Women known to have placenta accreta should be delivered by cesarean, and no attempt should be made to separate the placenta at the time of delivery. The majority of women with significant degrees of placenta accreta will require a hysterectomy. Although successful conservative management has been described, there are currently insufficient data to recommend this approach to management routinely. Vasa previa carries a risk of fetal exsanguination and death when the membranes rupture. The condition can be diagnosed prenatally by ultrasound examination. Good outcomes depend on prenatal diagnosis and cesarean delivery before the membranes rupture.

PMID 16582134  Obstet Gynecol. 2006 Apr;107(4):927-41. doi: 10.1097/01・・・
著者: D A Wing, R H Paul, L K Millar
雑誌名: Am J Obstet Gynecol. 1996 Oct;175(4 Pt 1):806-11.
Abstract/Text OBJECTIVE: Our purpose was to determine the safety, efficacy, and costs of inpatient and outpatient management of symptomatic placenta previa.
STUDY DESIGN: Fifty-three women with the initial diagnosis of placenta previa at 24 to 36 weeks' gestation who required hospitalization for vaginal bleeding were stabilized and then randomized to receive either inpatient or outpatient expectant management. Twenty-seven inpatients were placed at bed rest with minimal ambulation, received weekly corticosteroids until 32 weeks of gestation, and underwent ultrasonographic examination at 2-week intervals to assess fetal growth and placental location. Twenty-six outpatients were discharged home after > or = 72 hours of hospitalization. Each week they also received corticosteroids, until 32 weeks' gestation, and ultrasonographic evaluations. Outpatients with recurrent bleeding were readmitted for evaluation. All subjects who reached 36 weeks' gestation with persistent placenta previa underwent amniocentesis. When fetal lung maturity was present, cesarean delivery was electively performed.
RESULTS: There were insignificant differences between inpatients and outpatients for mean age, parity, race, type of previa (complete or partial), number of prior vaginal bleeding episodes, and initial hemoglobin value. The mean estimated gestational age at enrollment was 29.1 +/- 3.1 (SD) weeks for inpatients and 29.9 +/- 3.1 weeks for outpatients. In eight patients the placenta was found to no longer cover the internal os by 36 weeks' gestation. There were seven patients in each group who did not complete the protocol for initial treatment assignment. The average estimated gestational age at delivery for the inpatients was 34.5 +/- 2.4 weeks and 34.6 +/- 2.3 weeks for the outpatients (p = 0.90), whereas the mean birth weights were 2413.7 +/- 642.7 gm and 2607.8 +/- 587.1 gm, respectively (p = 0.28). Thirty-three patients (62.3%) had recurrent episodes of bleeding, with 26 requiring expeditious cesarean delivery. Four (14.8%) inpatients and one (3.7%) outpatient required blood transfusion (p = 0.67). There was no difference in neonatal morbidity (defined as the presence of respiratory distress syndrome, intracranial hemorrhage, or culture-proved sepsis) between the two groups (relative risk 1.16, 95% confidence interval 0.66 to 2.02). There were no neonatal deaths. The mean number of maternal hospital days differed significantly between the two groups: inpatients required an average of 28.6 +/- 20.3 days and outpatients remained hospitalized for an average of 10.1 +/- 8.5 days (p < 0.0001). Cost analysis based on maternal hospital days reveals a net savings of +15,080 per patient if women with symptomatic placenta previa initially diagnosed before 37 weeks' gestation are treated as outpatients.
CONCLUSIONS: For selected patients, outpatient management of symptomatic placenta previa appears to be an acceptable alternative to traditional conservative expectant inpatient management.

PMID 8885726  Am J Obstet Gynecol. 1996 Oct;175(4 Pt 1):806-11.
著者: J M Crane, M C Van den Hof, L Dodds, B A Armson, R Liston
雑誌名: Am J Perinatol. 2000;17(2):101-5. doi: 10.1055/s-2000-9269.
Abstract/Text The purpose of this study is to describe the maternal complications of placenta previa. A population-based retrospective cohort study including all women delivered in the province of Nova Scotia, Canada from 1988 to 1995 was performed. Patient information was obtained from the Nova Scotia Atlee Perinatal Database and maternal complications were described for all women undergoing cesarean delivery. Prognostic factors for the risk of hysterectomy in woman with placenta previa were analyzed by multiple logistic regression. During the 8-year period, 308 cases of placenta previa were identified in 93,996 deliveries (0.33%). Maternal complications included hysterectomy [relative risk (RR) = 33.26], antepartum bleeding (RR = 9.81), intrapartum (RR = 2.48), and postpartum (RR = 1.86) hemorrhages, as well as blood transfusion (RR = 10.05), septicemia (RR = 5.55), and thrombophlebitis (RR = 4.85). Risk factors for need of hysterectomy in women with placenta previa include the presence of placenta accreta and previous cesarean delivery.

PMID 11023169  Am J Perinatol. 2000;17(2):101-5. doi: 10.1055/s-2000-9・・・
著者: C M Zelop, B L Harlow, F D Frigoletto, L E Safon, D H Saltzman
雑誌名: Am J Obstet Gynecol. 1993 May;168(5):1443-8.
Abstract/Text OBJECTIVES: By means of hospital-based data over 9 years we sought to evaluate the clinical indications and incidence of emergency peripartum hysterectomy by demographic characteristics and reproductive history.
STUDY DESIGN: From the obstetric records of all deliveries at Brigham and Women's Hospital between Oct. 1, 1983, and July 31, 1991, we identified all women undergoing emergency peripartum hysterectomy, calculated crude and adjusted incidence rates, conducted statistical tests of linear trends and heterogeneity, and observed the clinical indications preceding the onset of this procedure.
RESULTS: There were 117 cases of peripartum gravid hysterectomy identified during this period, for an overall annual incidence of 1.55 per 1000 deliveries. The rate increased with increasing parity and was significantly influenced by placenta previa and a history of cesarean section. The incidence by parity increased from one in 143 deliveries in nulliparous women with placenta previa to one in four deliveries in multiparous women with four or more deliveries with placenta previa. Likewise, the incidence increased from one in 143 deliveries in women with one prior live birth and a prior cesarean section to one in 14 deliveries in multiparous women with four or more deliveries with a history of a prior cesarean section. Both these trends were highly significant (p < 0.001). Abnormal adherent placentation was the most common cause preceding gravid hysterectomy (64%, p < 0.001), with uterine atony accounting for 21%. Although no maternal deaths occurred, maternal morbidity remained high, including postoperative infection in 58 (50%), intraoperative urologic injury in 10 patients (9%), and need for transfusion in 102 patients (87%).
CONCLUSIONS: The data identify abnormal adherent placentation as the primary cause for gravid hysterectomy. The data also illustrate how the incidence of emergency peripartum hysterectomy increases significantly with increasing parity, especially when influenced by a current placenta previa or a prior cesarean section. Maternal morbidity remained high although no maternal deaths occurred.

PMID 8498425  Am J Obstet Gynecol. 1993 May;168(5):1443-8.
著者: S Iyasu, A K Saftlas, D L Rowley, L M Koonin, H W Lawson, H K Atrash
雑誌名: Am J Obstet Gynecol. 1993 May;168(5):1424-9.
Abstract/Text OBJECTIVE: Placenta previa can cause serious, occasionally fatal complications for fetuses and mothers; however, data on its national incidence and sociodemographic risk factors have not been available.
STUDY DESIGN: We analyzed data from the National Hospital Discharge Survey for the years 1979 through 1987 and from the Retrospective Maternal Mortality Study (1979 through 1986).
RESULTS: We found that placenta previa complicated 4.8 per 1000 deliveries annually and was fatal in 0.03% of cases. Incidence rates remained stable among white women but increased among black and other minority women (p < 0.1). In addition, the risk of placenta previa was higher for black and other minority women than for white women (rate ratio 1.3, 95% confidence interval 1.0 to 1.7), and it was higher for women > or = 35 years old than for women <20 years old (rate ratio 4.7, 95% confidence interval 3.3 to 7.0). Women with placenta previa were at an increased risk of abruptio placentae (rate ratio 13.8), cesarean delivery (rate ratio 3.9), fetal malpresentation (rate ratio 2.8), and postpartum hemorrhage (rate ratio 1.7).
CONCLUSION: Our findings support the need for improved prenatal and intrapartum care to reduce the serious complications and deaths associated with placenta previa.

PMID 8498422  Am J Obstet Gynecol. 1993 May;168(5):1424-9.
著者: Publications Committee, Society for Maternal-Fetal Medicine, Michael A Belfort
雑誌名: Am J Obstet Gynecol. 2010 Nov;203(5):430-9. doi: 10.1016/j.ajog.2010.09.013.
Abstract/Text OBJECTIVE: We sought to review the risks of placenta accreta, increta, and percreta, and provide guidance regarding interventions to improve maternal outcomes when abnormal placental implantation occurs.
METHODS: Relevant documents were identified through a search of the English-language literature for publications including ≥1 of the key words "accreta" or "increta" or "percreta" using PubMed (US National Library of Medicine; January 1990 through January 2010); with results limited to studies involving human beings. Additional information was obtained from references identified within selected articles; from additional review articles; and from guidelines by organizations including the American College of Obstetricians and Gynecologists. Each included article was evaluated according to study design and quality in accordance with the scheme outlined by the US Preventative Services Task Force.
RESULTS AND RECOMMENDATIONS: Abnormal placentation--encompassing placenta accreta, increta, and percreta--is increasingly common. While randomized controlled trials and large observational cohort studies that can be used to define best practice are lacking, strategies to enhance early diagnosis, enhance preparation, and coordinate peripartum management can be undertaken. Women with a placenta previa overlying a uterine scar should be evaluated for the potential diagnosis of placenta accreta. Women with a placenta previa or "low-lying placenta" overlying a uterine scar early in pregnancy should be reevaluated in the third trimester with attention to the potential presence of placenta accreta. When the diagnosis of placenta accreta is made remote from delivery, the need for hysterectomy should be anticipated and arrangements made for delivery in a center with adequate resources, including those for massive transfusion. Intraoperatively, attention should be paid to abdominal and vaginal blood loss. Early blood product replacement, with consideration of volume, oxygen-carrying capacity, and coagulation factors, can reduce perioperative complications.

Copyright © 2010. Published by Mosby, Inc.
PMID 21055510  Am J Obstet Gynecol. 2010 Nov;203(5):430-9. doi: 10.101・・・
著者: W Christopher Baughman, Jane E Corteville, Rajiv R Shah
雑誌名: Radiographics. 2008 Nov-Dec;28(7):1905-16. doi: 10.1148/rg.287085060.
Abstract/Text Placenta accreta (PA) encompasses various types of abnormal placentation in which chorionic villi attach directly to or invade the myometrium. PA is a significant cause of maternal morbidity and mortality and is now the most common reason for emergent postpartum hysterectomy. Its prevalence has risen tenfold in the United States over the past 50 years, primarily due to the increasing percentage of pregnant patients undergoing primary and repeat cesarean sections. Placenta previa and previous cesarean section are the two most important known risk factors for PA. Accurate prenatal identification of affected pregnancies allows optimal obstetric management. Ultrasonography (US) remains the diagnostic standard, and routine US examination at 18-20 weeks gestation affords an ideal opportunity to screen for the disorder. Placental lacunae and abnormal color Doppler imaging patterns are the most helpful US markers for PA. In recent years, there has been increased interest in magnetic resonance (MR) imaging for the evaluation of PA, since it can provide information on depth of invasion and more clearly depict posterior placentas. The most reliable MR imaging findings are uterine bulging, heterogeneous placenta, and placental bands. Focal interruptions in the hypointense myometrial border may also be helpful. PA is a clinical and diagnostic challenge that is being encountered with increasing frequency. Clinicians should be aware of the clinical issues, risk factors, and imaging findings associated with PA to facilitate optimal case management.

PMID 19001647  Radiographics. 2008 Nov-Dec;28(7):1905-16. doi: 10.1148・・・
著者: J I Yang, Y K Lim, H S Kim, K H Chang, J P Lee, H S Ryu
雑誌名: Ultrasound Obstet Gynecol. 2006 Aug;28(2):178-82. doi: 10.1002/uog.2797.
Abstract/Text OBJECTIVE: To investigate the value of transvaginal sonographic findings of intraplacental lacunae for predicting adherent placenta and clinical outcome in patients with placenta previa totalis and a history of Cesarean section.
METHODS: Fifty-one patients with placenta previa totalis diagnosed by transvaginal sonography and with a history of Cesarean section who delivered at our hospital were included in the study. The sonographic findings of intraplacental lacunae were classified into one of four grades. Pathological analysis of the placenta was performed for all patients who delivered, and in cases of hysterectomy, examination of the uterus was also performed. The placental findings and obstetric complications, including massive transfusion, intensive care unit admission and Cesarean hysterectomy, were compared with the grade of lacuna.
RESULTS: Lacunae were classified as Grade 1+ in 10 cases, Grade 2+ in 11 cases, Grade 3+ in five cases and as Grade 0 (i.e. lacunae were absent) in the remaining 25 cases. When lacunae of > or = Grade 1+ were considered, the sensitivity, specificity, positive predictive value and negative predictive value of diagnosing adherent placenta were 86.9%, 78.6%, 76.9% and 88.0%, respectively. When lacunae of > or = Grade 2+ were considered, the sensitivity, specificity, positive predictive value and negative predictive value of diagnosing placenta increta or percreta were 100%, 97.2%, 93.8% and 100%, respectively. Hysterectomy was performed in 18 cases, among whom two cases showed Grade 1+ lacunae, 11 cases showed Grade 2+ lacunae, and five cases showed Grade 3+ lacunae. No hysterectomy was performed in any case in which lacunae were absent. Compared to those without lacunae, the number of massive transfusions and intensive care unit admissions and cases of disseminated intravascular coagulopathy and Cesarean hysterectomy were significantly greater in those with lacunae (P < 0.0001).
CONCLUSION: Transvaginal sonographic findings of intraplacental lacunae in patients with placenta previa totalis and a history of Cesarean section are useful in the prediction of adherent placenta and may have a role in the prediction of clinical outcome.

PMID 16858740  Ultrasound Obstet Gynecol. 2006 Aug;28(2):178-82. doi: ・・・
著者: Carri R Warshak, Ramez Eskander, Andrew D Hull, Angela L Scioscia, Robert F Mattrey, Kurt Benirschke, Robert Resnik
雑誌名: Obstet Gynecol. 2006 Sep;108(3 Pt 1):573-81. doi: 10.1097/01.AOG.0000233155.62906.6d.
Abstract/Text BACKGROUND: The incidence of placenta accreta has increased dramatically over the last three decades, in concert with the increase in the cesarean delivery rate. Optimal management requires accurate prenatal diagnosis. The purpose of this study was to determine the precision and reliability of ultrasonography and magnetic resonance imaging (MRI) in diagnosing placenta accreta.
METHODS: A historical cohort study was performed with information gathered from our obstetric, radiologic, and pathology databases. Records from January 2000 to June 2005 were reviewed to identify patients with a diagnosis of placenta previa, low-lying placenta with a prior cesarean delivery, or history of a myomectomy to determine the accuracy of pelvic ultrasonography in the diagnosis of placenta accreta. The records of those considered to be suspicious for placenta accreta and subsequently referred for additional confirmation by MRI were also analyzed. The sonographic and MRI diagnoses were compared with the final pathologic or operative findings or with both.
RESULTS: Of the 453 women with placenta previa, previous cesarean delivery and low-lying anterior placenta, or previous myomectomy, 39 had placenta accreta confirmed by pathological examination. Ultrasonography accurately predicted placenta accreta in 30 of 39 of women and correctly ruled out placenta accreta in 398 of 414 without placenta accreta (sensitivity 0.77, specificity 0.96). Forty-two women underwent MRI evaluation because of findings suspicious or inconclusive of placenta accreta by ultrasonography. Magnetic resonance imaging accurately predicted placenta accreta in 23 of 26 cases with placenta accreta and correctly ruled out placenta accreta in 14 of 14 (sensitivity 0.88, specificity 1.0).
CONCLUSION: A two-stage protocol for evaluating women at high risk for placenta accreta, which uses ultrasonography first, and then MRI for cases with inconclusive ultrasound features, will optimize diagnostic accuracy.

PMID 16946217  Obstet Gynecol. 2006 Sep;108(3 Pt 1):573-81. doi: 10.10・・・
著者: Garrett Lam, Jeffrey Kuller, Michael McMahon
雑誌名: J Soc Gynecol Investig. 2002 Jan-Feb;9(1):37-40.
Abstract/Text OBJECTIVE: To determine whether magnetic resonance imaging (MRI) and ultrasound (US) are effective methods for diagnosing placenta accreta, increta, or percreta antenatally.
METHODS: We retrospectively reviewed radiologic reports of patients who had the diagnosis of placenta accreta, percreta, or increta by pathologic analysis. The gestational age at first ultrasound diagnosis of accreta and first MRI diagnosis of accreta was recorded. Ultrasound and MRI reports were examined for findings of a distorted retroplacental myometrial zone, disrupted uterine-bladder interface, focal exophytic masses, and presence of vascular placental lacunae. Surgical history, cesarean hysterectomy, and blood loss were also recorded.
RESULTS: Thirteen patients were identified, and 14 had true pathologic confirmation of accreta, increta, or percreta. Nine of thirteen had MRI, and of those, seven received gadolinium. Placenta accreta was diagnosed by MRI in five of nine patients, but only four were confirmed pathologically to have accreta. Four women who had a normal MRI had accreta confirmed by pathology (sensitivity 38%). Of the 13 patients who had US, four were considered to have an accreta, and these four had pathologic confirmation. Nine were negative for accreta by US; however, eight of those women had pathologic confirmation of accreta, and one was normal (sensitivity 33%).
CONCLUSION: Both MRI and US had poor predictive value in the diagnosis of placenta accreta, and further refinement in the techniques of both MRI and US is needed for these tests to be used to reliably diagnose these pathologic conditions.

PMID 11839507  J Soc Gynecol Investig. 2002 Jan-Feb;9(1):37-40.
著者: Judith A W Webb, Henrik S Thomsen, Sameh K Morcos, Members of Contrast Media Safety Committee of European Society of Urogenital Radiology (ESUR)
雑誌名: Eur Radiol. 2005 Jun;15(6):1234-40. doi: 10.1007/s00330-004-2583-y. Epub 2004 Dec 18.
Abstract/Text The use of iodinated or gadolinium-based contrast media in pregnant or lactating women often causes concerns in the radiology department because of the principle of not exposing a fetus or neonate to any drugs. Because of the uncertainty about the use of contrast media during pregnancy and lactation, the Contrast Media Safety Committee of the European Society of Urogenital Radiology decided to review the literature and draw up guidelines. An extensive literature search was carried out and summarized in a report. Based on the limited information available, simple guidelines have been drawn up. The report and guidelines were discussed at the 11th European Symposium on Urogenital Radiology in Santiago de Compostela, Spain. Mutagenic and teratogenic effects have not been described after administration of gadolinium or iodinated contrast media. Free iodide in radiographic contrast medium given to the mother has the potential to depress fetal/neonatal thyroid function. Neonatal thyroid function should be checked during the 1st week if iodinated contrast media have been given during pregnancy. No effect on the fetus has been seen after gadolinium contrast media. Only tiny amounts of iodinated or gadolinium-based contrast medium given to a lactating mother reach the milk, and only a minute proportion entering the baby's gut is absorbed. The very small potential risk associated with absorption of contrast medium may be considered insufficient to warrant stopping breast-feeding for 24 h following either iodinated or gadolinium contrast agents.

PMID 15609057  Eur Radiol. 2005 Jun;15(6):1234-40. doi: 10.1007/s00330・・・
著者: Morie M Chen, Fergus V Coakley, Anjali Kaimal, Russell K Laros
雑誌名: Obstet Gynecol. 2008 Aug;112(2 Pt 1):333-40. doi: 10.1097/AOG.0b013e318180a505.
Abstract/Text There has been a substantial increase in the use of computed tomography (CT) and magnetic resonance imaging (MRI) in pregnancy and lactation. Among some physicians and patients, however, there are misperceptions regarding risks, safety, and appropriate use of these modalities in pregnancy. We have developed a set of evidence-based guidelines for the use of CT, MRI, and contrast media during pregnancy for selected indications including suspected acute appendicitis, pulmonary embolism, renal colic, trauma, and cephalopelvic disproportion. Ultrasonography is the initial modality of choice for suspected appendicitis, but if the ultrasound examination is negative, MRI or CT can be obtained. Computed tomography should be the initial diagnostic imaging modality for suspected pulmonary embolism. Ultrasonography should be the initial study of choice for suspected renal colic. Ultrasonography can be the initial imaging evaluation for trauma, but CT should be performed if serious injury is suspected. Pelvimetry now is used rarely for suspected cephalopelvic disproportion, but when required, low-dose CT pelvimetry can be performed with minimal risk. Although iodinated contrast seems safe to use in pregnancy, intravenous gadolinium is contraindicated and should be used only when absolutely essential. It seems to be safe to continue breast-feeding immediately after receiving iodinated contrast or gadolinium. Although teratogenesis is not a major concern after exposure to prenatal diagnostic radiation, carcinogenesis is a potential risk. When used appropriately, CT and MRI can be valuable tools in imaging pregnant and lactating women; risks and benefits always should be considered and discussed with patients.

PMID 18669732  Obstet Gynecol. 2008 Aug;112(2 Pt 1):333-40. doi: 10.10・・・
著者: E R Newton, V Barss, C L Cetrulo
雑誌名: Am J Obstet Gynecol. 1984 Mar 15;148(6):743-8.
Abstract/Text The current case-controlled study examines the epidemiologic factors and subsequent clinical history in 139 patients with asymptomatic low placentation and 137 patients with normal placental position diagnosed in the second and third trimesters by gray-scale ultrasonography. Increased maternal age or parity and previous endometrial or myometrial damage were significantly associated with asymptomatic midtrimester low implantation. Three percent of early low implantations persisted as instances of placenta previa at term. However, in low implantation, the antepartum course was associated with perinatal complications in 45% of patients. Statistically significant increases in third-trimester bleeding, abruptio placentae, and suspected intrauterine growth retardation were shown in the patients with low implantation, when compared to the control patients. Forty-two percent of the patients with low implantation were delivered by cesarean section. The need for cesarean delivery, loss of blood, and prolonged hospitalization were statistically increased in the patients with low implantation. Infants born to mothers with low implantation showed statistically significant increases in prematurity, low birth weight, and perinatal mortality when compared to infants born to control patients.

PMID 6702943  Am J Obstet Gynecol. 1984 Mar 15;148(6):743-8.
著者: D B Cotton, J A Read, R H Paul, E J Quilligan
雑誌名: Am J Obstet Gynecol. 1980 Jul 15;137(6):687-95.
Abstract/Text One hundred and seventy-three cases of placenta previa managed at the Women's Hospital of Los Angeles County-University of Southern California Medical Center from July, 1975, through June, 1978, were reviewed and compared to a similar series of cases studied in the same institution in 1969. The perinatal mortality of 12.6% was roughly one half of that in the earlier study. The fetal death rate did not change significantly, but the neonatal mortality was markedly less, especially in the 27-to-32-week range. Expectant management was employed in 65.8% of patients, as compared to 42.6% in 1969. The higher rate of expectant management was characterized by the aggressive use of antepartum transfusions in the face of moderate-to-severe bleeding in lieu of delivery, as well as the occasional use of tocolytic agents for inhibition of premature labor in the presence of vaginal bleeding. Elective termination of pregnancy utilizing the lecithin/sphingomyelin (L/S) ratio for determination of pulmonary maturation also resulted in significantly less overall neonatal morbidity and mortality. These multiple factors appear to have contributed to a dramatic reduction in the perinatal mortality associated with placenta previa.

PMID 7395932  Am J Obstet Gynecol. 1980 Jul 15;137(6):687-95.

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