Fetal magnetic resonance imaging enhances detection of spinal cord anomalies in patients with sonographically detected bony anomalies of the spine.

OBJECTIVE: Although fetal magnetic resonance imaging (MRI) is being increasingly used to evaluate sonographically suspected abnormalities, its utility in the evaluation of the spinal canal is not well studied. Because it is not susceptible to the limitations of fetal position, oligohydramnios, and shadowing from bony structures, we hypothesize that fetal MRI is better suited to assess the contents of the spinal canal compared with prenatal sonography. The purpose of this investigation was to determine whether fetal MRI could detect spinal abnormalities in cases in which they had not been originally suspected on prenatal sonography. METHODS: Fetal spine MR images were retrospectively reviewed over a 42-month period. Corresponding sonographic images were then rereviewed to determine whether there were findings in retrospect that might have suggested the cord abnormalities. Cases of myelomeningocele were counted as a spinal cord abnormality only if fetal MRI showed a cord anomaly other than the myelomeningocele. RESULTS: Of 33 cases referred for bony anomalies of the spine, fetal MRI showed additional abnormalities involving the spinal cord in 3 patients. These included diastematomyelia in 2 cases and segmental spinal dysgenesis in the third case. One case of diastematomyelia occurred in association with a lumbosacral myelomeningocele. The spinal cord anomalies were not visible on any of the prenatal sonograms, even in retrospect. CONCLUSIONS: Additional spinal cord anomalies were detected in 10% of cases reviewed. Fetal MRI can be useful in assessing the spinal cord in fetuses with bony spinal anomalies. Our findings suggest that fetuses with sonographically diagnosed bony abnormalities of the spine may benefit from further evaluation with fetal MRI.     

Sonographic findings and fetal chromosomal studies undertaken prenatally by fetal blood sampling using cordocentesis.

Prenatal karyotyping was carried out on 206 pregnancies with sonographic abnormalities, including fetal malformations, growth retardation and disorders of the amniotic fluid volume. Overall, chromosomal aberrations were detected in 37 cases (18.0%), but the frequency of chromosomal aberrations was 8.2% in fetuses with a single anomaly and 52.7% in fetuses with multiple anomalies. The chromosomal risk was very high in malformations associated with growth retardation (81.8%) or with both growth retardation and disorders of the amniotic fluid volume (82.4%). High rates of chromosomal aberrations were observed in cases of heart anomalies, diaphragmatic hernia, urinary tract obstruction, hydrocephalus, intestinal atresia, abdominal wall defect and fetal effusion/hydrops. In fetuses at high risk of chromosomal aberrations, cordocentesis for rapid karyotyping is justified in the second or third trimester.     

胎儿泌尿生殖系统畸形产前超声及磁共振成像诊断分析

目的探讨产前超声及磁共振成像（MRI）诊断胎儿泌尿生殖系统畸形的应用指征和临床作用。 方法对产前超声诊断为泌尿生殖系统畸形的227例胎儿均于24 h内行MRI检查,与产后检查和临床随访结果对照,对产前超声漏误诊病例的图像特征进行分析。 结果产前超声检出泌尿生殖系统畸形的227例胎儿中包括肾脏囊性病变70例、梗阻性尿路疾病41例、肾缺如40例、肾位置异常24例、融合肾18例、重复肾17例、肾肿瘤8例、双肾体积小3例、膀胱病变5例、阴茎短小1例。与产后检查及临床随访结果对照,产前超声正确诊断胎儿泌尿生殖系统畸形194例（85.5%,194/227）;漏误诊33例（14.5%,33/227）,其中15例（1例输尿管息肉）梗阻性尿路疾病不能显示输尿管狭窄或梗阻部位、3例梗阻性尿路疾病不能明确诊断（1例巨输尿管、2例肾积水）、3例梗阻性尿路疾病误诊为重复肾;其余12例漏误诊病例包括3例肾位置异常、2例重复肾合并囊性肾发育不良、2例肾缺如、2例融合肾、1例多囊肾合并重度积水、1例重复肾、1例阴茎短小。产前MRI正确诊断224例（98.7%,224/227）;漏诊3例（1.3%,3/227）。另外,3例泌尿系统异常伴发的生殖器异常,产前超声、MRI均未显示,均为产后发现。 结论产前超声及MRI对胎儿泌尿系统畸形有较高显示率;但超声及MRI对胎儿生殖器畸形的显示率均不高。明确MRI应用指征有助于产前合理选用影像学检查方法,对诊断和佐证胎儿泌尿生殖系统畸形有重要临床作用。     

MRI of fetal abdominal abnormalities

Although ultrasonography is the method of choice for evaluating the fetus, magnetic resonance imaging (MRI) complements ultrasonography in the accurate diagnosis of fetal abnormalities. The advantages of MRI include excellent tissue contrast, a large field of view, and relative operator independence. To date, most studies on fetal MRI have focused on the fetal central nervous system and thoracic disorders. However, our experience suggests that MRI can be helpful even in evaluating fetal abdominal disorders. This pictorial essay illustrates the various MRI appearances of fetal abdominal abnormalities and discusses the indications and advantages of fetal MRI.     

羊水过少时胎儿畸形的磁共振诊断价值

目的：评价磁共振成像（MRI）对羊水过少时胎儿畸形的诊断价值。方法：回顾性分析18例超声筛查出羊水过少胎儿的MRI，并将超声、MRI结果与引产后或出生后随访结果对照。通过MRI采用感兴趣区工具（ROI）测量胎儿肺肝信号强度比（LLSIR），采用t检验进行统计学分析。结果：18例羊水过少胎儿MRI均能清晰显示其结构．泌尿系统畸形13例（其中同时伴肺发育不良6例、同时伴肺发育不良和心脏畸形2例、人体鱼序列征1例、中枢神经系统畸形1例、单脐动脉1例），腹腔囊肿2例，中枢神经系统畸形1例，2例胎儿无明显畸形。除3例引产未尸检外，其余MRI结果均由出生或引产后结果证实。结论：MRI是羊水过少时胎儿畸形有效的影像诊断方法，它能明确诊断羊水过少时的胎儿肾脏及肺异常，发挥超声的重要补充作用，尤其是超声显示不清时。     

超声和MRI联合应用诊断胎儿胸部异常

目的对比分析二维超声(2DUS)和磁共振成像(MRI)在胎儿胸部异常诊断中的应用价值及各自的优势与劣势,探讨超声和MRI联合应用诊断胎儿胸部异常的临床价值。方法 42例超声诊断为胸部异常(不包括心脏畸形)的胎儿,征得患者同意在接受超声检查后24 h内行MRI检查,最终诊断由产后尸检或生后随访证实。回顾性分析42例胎儿的超声和MRI图像,并与随访结果对照。结果 42例胸部异常包括先天性肺囊腺瘤畸形(CCAM)19例,隔离肺(BPS)9例,先天性膈疝(CDH)11例,先天性高位气道闭锁综合征(CHAOS)1例,膈膨升1例,胸腺增大1例。超声检出并正确诊断例数为38例(38/42),MRI检出并正确诊断例数为39例(39/42)。超声和MRI对胎儿胸部异常检出例数比较差异无统计学意义(P0.05)。结论虽然超声和MRI在胎儿胸部异常检出例数方面无差异,但其各有优劣势,超声和MRI联合应用在部分病例中可综合评价胸部异常引起的继发改变,如超声可动态观测患儿心功能状态,MRI可明确病灶界限及评价肺发育情况。     

Ultrasound and fetal magnetic resonance imaging: Clinical performance in the prenatal diagnosis of orofacial clefts and mandibular abnormalities

Cleft lip, with or without cleft palate, is the most common congenital craniofacial anomaly and the second most common birth defect worldwide. Micrognathia is a rare facial malformation characterized by small, underdeveloped mandible and frequently associated with retrognathia. Second- and third-trimester prenatal ultrasound is the standard modality for screening and identification of fetal orofacial abnormalities, with a detection rate in the low-risk population ranging from 0% to 73% for all types of cleft. The prenatal ultrasonography detection can also be performed during the first trimester of pregnancy. Given the potential limitations of obstetric ultrasound for examining the fetal face, such as suboptimal fetal position, shadowing from the surrounding bones, reduce amniotic fluid around the face, interposition of fetal limbs, umbilical cord and placenta, and maternal habitus/abdominal scars, the use of adjunct imaging modalities can enhance prenatal diagnosis of craniofacial anomalies in at-risk pregnancies. Fetal magnetic resonance imaging (MRI) is a potentially useful second-line investigation for the prenatal diagnosis of orofacial malformations with a pooled sensitivity of 97%. In this review, we discuss the role of ultrasound and fetal MRI in the prenatal assessment of abnormalities of the upper lip, palate, and mandible.     

MRI of fetal GI tract abnormalities

We describe the magnetic resonance (MR) patterns of a variety of fetal gastrointestinal (GI) abnormalities. Thirty-two fetuses between 23 and 38 weeks gestation with abnormal appearance of the GI tract by ultrasound underwent MR imaging with T1- and T2-weighted sequences. The MR aspect of intestinal atresia (duodenal atresia, one case; small bowel atresia, nine cases) included dilatation of the bowel loops, accurate assessment of the normal bowel distal to the atresia (except in the patient with multiple atresia and apple-peel syndrome), and micro-rectum with decreased T1 signal (except in the patient with duodenal atresia). Megacystis-microcolon-intestinal hypoperistalsis syndrome (one case) was indicated by an abnormal signal of the entire bowel and an abnormal pattern for the urinary tract. Meconium pseudocysts (two cases) were easily differentiated from enteric cysts (two cases). High anorectal malformations with (two cases) or without (one case) urinary fistula and cloacal malformation (one case) are described and MR findings are discussed. The capability of MR imaging to demonstrate the normal bowel with intraperitoneal anomalies (e.g., congenital diaphragmatic hernia, and sacrococcygeal teratoma) is emphasized. MR imaging is informative in the diagnosis of GI tract abnormalities, especially the severe malformations, with much more accuracy than sonography.     

Ultrasound in abdominal tuberculosis

Background: The present study was done to emphasize the importance of ultrasound (US) and US-guided fine-needle aspiration biopsy (FNAB) in the diagnosis of abdominal tuberculosis. Methods: Sixty-six proven cases of abdominal tuberculosis were selected for this study. The diagnosis was based on clinical features, US observations, FNAB, operative findings, and responses to appropriate antitubercular treatment. The US findings were interpreted with regard to the involvement of lymph nodes, intestine, peritoneum, solid viscera, and abdominal abscesses. Patients with disease limited to the musculoskeletal and genitourinary systems were not included in the study. Results: Peritoneal tuberculosis was the most common form, of the wet ascitic type. Ascites was clear in 19 patients and complex in 17. Tuberculous lymphadenopathy was seen in 37 patients. There was a predilection of periportal, peripancreatic, and mesenteric locations compared with the degree of retroperitoneal involvement. Calcification and heterogeneous echotexture were seen in seven cases. FNAB confirmed the diagnosis of tubercular lymphadenopathy in 19 patients. Intestinal disease was seen in 14 patients. Hepatic or splenic involvement was seen as diffuse organomegaly; less commonly, focal lesions were seen. Conclusion: This combination of US findings in proper clinical settings are diagnostic of tuberculosis. FNAB confirms the diagnosis in lymphadenopathy, abscesses, and focal lesions of the viscera.     

胎儿胼胝体发育不良的超声和磁共振对比观察

目的 探讨超声与MRI在胎儿胼胝体发育不良(ACC)产前诊断中的应用价值。方法 超声怀疑胎儿ACC孕妇16名,均在超声检查后3天内接受胎儿MR检查。将超声、MRI结果与出生后或引产后结果对照。结果 16名孕妇共检出胎儿16胎,MRI证实14胎为胎儿ACC(出生后随访证实5胎,引产后证实9胎),1胎为单纯双侧脑室扩张伴灰质易位,1胎为脑白质、脑干发育不良。MRI与超声比较,诊断胎儿ACC一致者7胎;超声可疑、MRI肯定者7胎;对于其伴发中枢神经系统畸形,两者一致者7胎,MRI多于超声者4胎。结论 超声检查是产前筛查胎儿ACC的普遍方法;MRI对胎儿ACC的显示明显优于超声,有助于明确诊断胎儿ACC并判断其分型及合并畸形。     

Fetal genitourinary anomalies--a pictorial review with postnatal correlation

An accurate diagnosis of fetal genitourinary abnormality is essential because some genitourinary abnormalities are associated with pulmonary hypoplasia, which ultimately affects the neonatal outcome. Adrenal masses are rare; however, presence of any lesion located at the superior pole of the kidney should raise the possibility of an adrenal mass. Fetal genital anomalies are rare as well and some of the most difficult to diagnose. A combination and pattern of findings allows for specific diagnosis of renal tract abnormalities. This article reviews the imaging appearance of fetal genitourinary abnormalities with perinatal imaging correlation where available.     

Oligohydramnios associated with bilateral multicystic dysplastic kidneys: prenatal diagnosis at 15 weeks' gestation

Lethal fetal renal malformations are invariably associated with oligohydramnios in late antennatal ultrasound examinations. Controversy exists concerning the contribution of fetal urine production to amniotic fluid volume prior to 20 weeks' gestation. We report a pregnancy complicated by maternal gold usage and fetal bilateral multicystic dysplastic kidney disease in which oligohydramnios was detected at 12 weeks' gestation. To our knowledge, no previous cases of lethal fetal renal anomalies have been made in the first trimester. The early diagnosis of fetal renal anomalies, fetal renal contribution to amniotic fluid production, and possible teratogenicity of gold therapy is discussed.     

胎儿肠管扩张与妊娠结局相关性分析

目的探讨胎儿肠管扩张产前超声异常表现及妊娠结局相关性。方法对2009年7月至2013年6月在南京医科大学附属苏州医院苏州市立医院产前超声检出肠管扩张的118例胎儿超声声像图表现及妊娠结局进行总结分析。结果118例胎儿产前超声表现及妊娠结局：（1）小肠扩张101例：98例肠管轻度扩张,最宽内径为7．2～22．6mm,31例合并唇腭裂、羊水过多、肠管强回声等其他异常超声表现。1例唇腭裂胎儿于妊娠25周引产,97例妊娠结局良好;3例肠管明显扩张,超声动态观察肠管进行性增宽,最宽内径均超过30．0mm,伴羊水持续增多,妊娠34周宫内死亡2例,1例出生后1周因肠梗阻死亡。（2）结肠扩张17例,16例34周后发现结肠扩张,最宽内径均小于30．0mm,伴羊水过多或减少,胎儿肠管强回声等软指标异常,妊娠结局良好;1例中孕期发现羊水过多及胎儿下腹部“双叶征”团块,产后证实为肛门闭锁。结论肠管扩张胎儿多数在超声随访过程证实为一过性肠管扩张,妊娠结局转归良好：但肠管扩张动态观察过程中小肠内径持续增宽,扩张程度加重、羊水量持续增多,胎儿妊娠结局不良;如检出胎儿肠管强回声,发生肠梗阻的可能性较低;超声检查怀疑结肠梗阻及肛门闭锁的胎儿,观察肠道形态变化更有意义。     

Hepatic iron overload: Diagnosis and quantification by noninvasive imaging

The diagnostic efficacy of magnetic resonance (MR) and computed tomography (CT) for detection and quantification of hepatic iron was assessed in a series of patients under investigation for clinical or biochemical evidence of hepatic iron overload. Thirty patients underwent MR imaging (SE 30,60/1000 or SE 30,60/2000) at 0.5 Tesla with calculation of hepatic T2 and liver to paraspinous muscle signal intensity ratios. Twenty-nine patients also had measurement of hepatic attenuation on noncontrast CT images. Results of these imaging studies were correlated in all patients with quantitative iron determination from liver biopsy specimens. The best predictor of liver iron among parameters studied was the ratio of the signal intensities of liver and paraspinous muscle (L/M) on a SE 60/1000 sequence. Both MR using L/M ratios and CT were sensitive methods for detection of severe degrees of hepatic iron overload with 100% of patients with hepatic iron on biopsy > 600 g/ 100 mg liver dry weight detected on the basis of L/M <0.6 or CT attenuation >70 Hounsfield units (HU). The MR parameter, however, was more specific than CT (100 vs 50%) and showed a higher degree of correlation with quantitated hepatic iron from biopsy. T2 measurements showed poor correlation with hepatic iron, due to difficulty in obtaining precise T2 measurements in vivo when the signal intensity is low. None of the parameters utilized was sensitive for detecting mild or moderate degrees of hepatic iron overload.We conclude that MR and CT are sensitive techniques for noninvasive detection of severe hepatic iron overload, with MR providing greater specificity than CT. Lesser degrees of iron deposition, however, may go undetected by our current imaging techniques.     

Fetal magnetic resonance imaging in the evaluation of fetuses referred for sonographically suspected abnormalities of the corpus callosum.

OBJECTIVE: Fetal magnetic resonance imaging (MRI) has been shown to be useful in assessing the developing central nervous system. However, its utility in specific brain disorders has not been well investigated. We hypothesized that fetal MRI can better assess the integrity of the brain in cases with sonographically suspected callosal abnormalities. METHODS: We retrospectively reviewed fetal MRI and prenatal sonographic studies of 10 fetuses referred for MRI for sonographically suspected callosal abnormalities. RESULTS: An abnormal corpus callosum was identified on fetal MRI in 80% of cases. The type of callosal abnormality (complete or partial agenesis) was similar on both prenatal sonography and fetal MRI in all cases. All sonographically identified additional brain abnormalities were detected on fetal MRI, with the exception of choroid plexus cysts. Furthermore, in 63% (5 of 8) of cases with a callosal abnormality on both sonography and fetal MRI, additional brain abnormalities were detected on fetal MRI that were not apparent on sonography. These sonographically occult findings were confirmed on postnatal MRI or autopsy in 3 of 5 patients. CONCLUSIONS: Fetal MRI is an important adjunct to sonography in assessing the corpus callosum and other aspects of brain development when agenesis of the corpus callosum is suspected. It can identify frequent additional findings that are not visible on sonography such as abnormal sulcation. In light of the association between additional brain abnormalities and worse neurodevelopmental outcome, the potential of fetal MRI as an important adjunctive prognostic imaging test in fetuses with callosal agenesis can now be tested.     

Fetal echogenic bowel: parameters to be considered in differential diagnosis.

OBJECTIVES: To evaluate the extent that associated findings aid in the differential diagnosis and/or prognosis of fetal echogenic bowel. METHODS: Medical history, obstetric records and outcome details were examined for 131 consecutive pregnancies with fetal hyperechogenic bowel. RESULTS: In 62 (47%) cases, there were no visible anomalies other than hyperechogenic bowel and no evidence of growth restriction. This group included four (7%) pregnancies with Down syndrome, 15 (24%) with infection or a recent episode of influenza and eight (13%) with blood staining of amniotic fluid. In the remaining 69 (53%) cases, hyperechogenic bowel was accompanied by hydrops or nuchal edema (n = 16, 12.2%), growth restriction (n = 9, 6.9%), other markers for chromosome anomalies (n = 33, 25.2%) or multiple structural anomalies (n = 11, 8.4%). In this group, the prevalence of Down syndrome was 12%, infection or influenza was reported in 14 (20%) cases and there was blood staining of amniotic fluid in seven (10%). Cystic fibrosis screening was performed in 65 (50%) pregnancies; the results were negative in all cases and clinical assessment did not indicate cystic fibrosis in any of the 91 infants who were born alive. Maternal serum screening was performed in 41 (31%) pregnancies. High alpha-fetoprotein levels were associated with multiple abnormalities or severe growth restriction. CONCLUSIONS: In many pregnancies with fetal hyperechogenic bowel, there are multiple factors that may explain these findings. Thus identification of one potential underlying cause should not preclude further testing. Once chromosome defects, cystic fibrosis, structural abnormalities, infection and growth restriction have been excluded, parents can be counseled that the prognosis is good, irrespective of the presence or absence of blood stained amniotic fluid.     

胎儿泌尿生殖系统异常的磁共振诊断

目的 探讨磁共振成像(MRI)在胎儿泌尿生殖系统异常诊断中的价值。方法 回顾性分析72例随访证实为泌尿生殖系统异常胎儿的产前MRI, 其中泌尿系统61例、生殖系统11例,孕龄21~39周,平均29周, 以胎儿出生后或引产后随访结果为参考标准,与产前MRI、US诊断结果对比分析。通过MRI采用感兴趣区工具(ROI)测量胎儿肺肝信号强度比(LLSIR),采用t检验进行统计学分析。结果 61例泌尿系异常其中肾不发育9例(同时伴肺发育不良2例),盆腔异位肾2例,多囊性发育不良肾15例(同时伴肺发育不良5例),梗阻性尿路疾病23例(其中重复畸形或输尿管异位开口3例、同时伴肺发育不良1例),肾发育不良9例(同时伴肺发育不良3例),脐尿管囊肿2例(1例合并睾丸鞘膜积液),左肾上腺神经母细胞瘤1例;11例生殖系统异常其中卵巢囊肿8例,睾丸鞘膜积液2例,右卵巢畸胎瘤1例,其中1例睾丸鞘膜积液存在全身水肿,1例卵巢囊肿还存在脑发育不良及右心房增大。MRI诊断准确率为95.8％。11例羊水过少肺发育不良胎儿LLSIR为1.06~1.29,平均值为1.20±0.08,较正常明显减低(P=0.000<0.05)。结论 MRI是胎儿泌尿生殖系统异常较有价值的产前影像诊断方法。能提供超声以外的信息,发挥超声的重要补充作用,尤其是超声显示不清时。     

Preliminary experience with cardiovascular magnetic resonance in evaluation of fetal cardiovascular anomalies

Background

The cardiovascular system is the part of the fetal anatomy that most frequently suffers from congenital pathology. This study shows our preliminary experience with fetal cardiovascular magnetic resonance (CMR) to evaluate congenital cardiovascular abnormalities.

Methods

Between January 2006 and June 2011, Prenatal routine obstetric ultrasound (US), echocardiography and CMR data from 68 pregnant women carrying fetuses with congenital cardiovascular anomalies were compared with postnatal diagnoses (postnatal imagings, surgery and autopsy). All prenatal CMR was performed at 1.5 T. Imaging sequences included steady-state free-precession (SSFP) sequences, real-time SSFP and single-shot turbo spin echo (SSTSE) sequences. The images were analyzed with an anatomic segmental approach by two radiologists.

Results

Fetal CMR yielded the same diagnosis as postnatal findings in 79% (54/68) of patients. The diagnostic sensitivity of routine obstetric US for cardiac anomalies was 46% (31/68). The diagnostic sensitivity of fetal echocardiographic examination by a fetal cardiac specialist was 82% (56/68). In 2 (3%) of 68 cases, diagnoses with both echocardiography and CMR were incorrect when compared with postnatal diagnosis. In ten (15%) cases, diagnosis at echocardiography was incorrect and that at CMR was correct. In twelve (18%) cases, diagnosis at echocardiography was correct and that at CMR was incorrect. Ten cases missed or misdiagnosed by echocardiography but correctly diagnosed by fetal CMR included asplenia syndrome (n = 2), interrupted inferior vena cava of polysplenia syndrome (n = 1), tricuspid incompetence (n = 1), double outlet right ventricle (n = 2), double aortic arch (n = 1), right pulmonary artery hypoplasia (n = 1), right-sided aortic arch of tetralogy of Fallot (n = 1) and hypoplastic left heart syndrome of a twin fetus (n = 1).

Conclusion

Fetal CMR is a promising diagnostic tool for assessment of congenital cardiovascular abnormalities, especially in situations that limit echocardiography.     

Longitudinal evaluation of azithromycin and cytokine concentrations in amniotic fluid following one‐time oral dosing in pregnancy

To utilize noninvasive collection of amniotic fluid in the setting of preterm premature rupture of membranes (PPROMs) to report the time concentration profile of azithromycin in amniotic fluid over 7 days from a single dose, and evaluate the correlation between azithromycin concentration and inflammatory markers in amniotic fluid. Prospective cohort study of five pregnant patients admitted with PPROMs and treated with a single 1 g oral azithromycin dose. Amniotic fluid was collected from pads and used to quantify azithromycin concentration as well as TNFa, IL‐1a, IL‐1b, IL‐6, IL‐8, and IL‐10 concentrations. Primary outcome was time/concentration profile of azithromycin in amniotic fluid. Secondary outcome included correlation between azithromycin concentration and cytokine concentrations. Five patients were enrolled. Mean gestational age on admission with PPROM was 27.5 ± 2.3 weeks with a median latency of 7 days (interquartile range [IQR] = 4–13). A median of two samples/day (IQR = 1–3) were collected per participant. Azithromycin was quantified in duplicate; intra‐assay coefficient of variation was 17%. Azithromycin concentration was less than 60 ng/ml after day 3. Azithromycin concentration was positively correlated with IL‐8 (r = 0.38, p = 0.03), IL1a (r = 0.39, p = 0.03), and IL‐1b (r = 0.36, p = 0.04) in amniotic fluid. Azithromycin is detectable in amniotic fluid over 7 days from a single 1 g maternal dose, however, it is not sustained over the range of minimum inhibitory concentration for common genitourinary flora. Based on correlation with specific cytokines, azithromycin penetration in amniotic fluid may relate to maternal monocyte concentration in amniotic fluid in the setting of PPROM.

Study Highlights

• WHAT IS THE CURRENT KNOWLEDGE ON THE TOPIC?

Azithromycin is used to prevent infection in setting of preterm premature rupture of membranes (PPROMs), but there is no established dose. One cross‐sectional study with one patient found amniotic fluid azithromycin concentration was below minimum inhibitory concentration (MIC)50 of common genitourinary (GU) flora 7 days after a single 1 g maternal dose. There is no reported correlation between maternal azithromycin treatment and the concentration of drug and inflammatory cytokines in amniotic fluid.

• WHAT QUESTIONS DID THIS STUDY ADDRESS?

Our objective was to utilize noninvasive collection of amniotic fluid in pregnant patients admitted with PPROM to address whether one‐time maternal dosing of azithromycin can produce a sustained amniotic fluid concentration greater than the MIC of common GU flora over 7 days, and secondarily, whether amniotic fluid azithromycin concentration was correlated with inflammatory cytokine concentrations.

• WHAT DOES THIS STUDY ADD TO OUR KNOWLEDGE?

Azithromycin is detectable in amniotic fluid over 7 days from a single 1 g maternal dose, however, it is not sustained over the range of MIC for common GU flora. Azithromycin concentration in amniotic fluid is correlated with specific cytokines that suggest that azithromycin penetration in amniotic fluid may relate to maternal monocyte concentration in amniotic fluid in the setting of PPROM.

• HOW MIGHT THIS CHANGE CLINICAL PHARMACOLOGY OR TRANSLATIONAL SCIENCE?

Amniotic fluid may be collected noninvasively from patients with PPROM and used to evaluate the fetal environment, including medication penetrance and inflammatory markers. Given the benefit of maternal and fetal exposure to azithromycin for prevention of adverse perinatal outcomes, it is important to study how maternal dosing leads to azithromycin concentration within the maternal fetal unit in order to optimize therapy.     

Significance of nonvisualization of the fetal urinary bladder.

The fetal urinary bladder was visualized sonographically in 1254 (94%) of 1335 consecutive fetuses of 14 weeks of development or older, but it could not be seen in 81 cases (6%). Five of these cases were lost to follow-up and were excluded from the study. Of the remaining 76 cases, 69 (91%) of the pregnancies progressed to term, and the infants were normal at birth and at 6 week perinatal follow-up. Seven (9%) of the fetuses had a variety of associated obstetrical abnormalities that resulted in fetal demise or termination of the pregnancy (oligohydramnios, hydrops, intrauterine growth retardation [IUGR], ventriculomegaly, diaphragmatic hernia, cystic hygroma, and triploidy). Notably, none of these were renal tract anomalies. We concluded that (1) nonvisualization of the fetal urinary bladder with an otherwise normal sonogram, including normal volume of amniotic fluid and normal renal areas, is of no clinical concern and does not require follow-up, and (2) nonvisualization of the fetal urinary bladder in the setting of associated obstetrical abnormalities may be secondary to renal tract anomalies or may only be a consequence of the associated abnormalities.