We conduct clinical and laboratory research in maternal and fetal diseases responsible for excessive infant mortality in the United States, focusing on the mechanisms of disease responsible for pre-term delivery with particular emphasis on the role of maternal and fetal inflammation and subclinical infection. This year, we studied the frequency of intra-amniotic infection in women presenting with vaginal bleeding during pregnancy, the role of complement activation in the Great Obstetrical syndromes, and the clinical value of cervical sonography and fetal fibronectin in the prediction of spontaneous pre-term birth. The prenatal diagnosis of congenital anomalies is also a major area of interest. Advances in imaging techniques, particularly ultrasound, have allowed the in utero detection of many anatomical defects. Our goal is to improve the prenatal diagnosis and treatment of fetal diseases and congenital anomalies. To that end and with the use of three-dimensional ultrasound, we have initiated a series of projects to improve their detection and assess fetal growth and development. Given that congenital heart disease is the leading cause of death among fetuses with congenital anomalies, we have sought to develop techniques for its diagnosis.
Frequency and clinical significance of microbial invasion of the amniotic cavity in patients with vaginal bleeding
Romero, Nien
Premature birth is the leading cause of perinatal mortality and morbidity worldwide. We have defined pre-term labor as a syndrome and determined that at least 25 percent of pre-term neonates are born to women with proven subclinical intrauterine infection. Moreover, we have provided evidence that many premature neonates are critically ill before birth and proposed that, in the context of intrauterine infection, the onset of pre-term labor has survival value.
Although vaginal bleeding is the most common complication of pregnancy (25 percent of all pregnant women have bleeding during pregnancy), the causes of this complication remain largely unknown. Bleeding is a risk factor for adverse pregnancy outcome (e.g., pre-term premature rupture of membranes, intrauterine growth restriction, and so forth). We conducted a retrospective cohort study of women who presented with vaginal bleeding between 18 and 35 weeks and who had undergone amniocentesis for assessment of the microbiologic status of the amniotic cavity and/or fetal lung maturity. Amniocentesis detected microbial invasion of the amniotic cavity in 14 percent of cases. Patients with vaginal bleeding and a gestational age less than 28 weeks at the time of amniocentesis had a significantly higher frequency of microbial invasion of the amniotic cavity than those with a gestational age greater than 28 weeks. Ureaplasma urealyticum was the microorganism most frequently isolated from the amniotic fluid. Except for one case, all patients with microbial invasion of the amniotic cavity had an early pre-term delivery. Patients with vaginal bleeding and microbial invasion of the amniotic cavity had a shorter procedure-to-delivery interval than those without microbial invasion of the amniotic cavity. These observations suggest that vaginal bleeding may be the only clinical manifestation of microbial invasion of the amniotic cavity and predisposes to adverse pregnancy outcome.
Gomez R, Romero R, Nien JK, Medina L, Carstens M, Kim YM, Chaiworapongsa T, Espinoza J, Gonzalez R. Idiopathic vaginal bleeding during pregnancy as the only clinical manifestation of intrauterine infection. J Matern Fetal Neonatal Med 2005;18:31-37.
Short uterine cervix as a risk factor for microbial invasion of the amniotic cavity in women presenting with pre-term labor and intact membranes
Romero, Nien; in collaboration with Kim Y
Women with microbial invasion of the amniotic cavity are at greater risk for adverse maternal and neonatal outcome. However, microbial invasion of the amniotic cavity is subclinical in nature, and its identification requires amniocentesis. We conducted a study to determine if women who present with pre-term labor and a short cervix, as determined by sonographic examination, had a higher rate of culture-proven microbial invasion of the amniotic cavity than those without a short cervix. We performed ultrasonography and amniocentesis on 401 patients admitted with pre-term labor (22 to 35 weeks) and cervical dilatation of less than or equal to 3 cm, as assessed by digital examination. The prevalence of microbial invasion of the amniotic cavity was 7 percent. Patients with a cervical length less than 15 mm had a higher rate of positive amniotic fluid culture than patients with a cervical length greater than or equal to 15 mm. Women with a long cervix were at low risk for microbial invasion of the amniotic cavity and spontaneous pre-term delivery. Our study suggests that endovaginal ultrasonographic examination of the uterine cervix is useful for identifying women at risk for intrauterine infection.
Gomez R, Romero R, Nien JK, Chaiworapongsa T, Medina L, Kim YM, Yoon BH, Carstens M, Espinoza J, Iams JD, Gonzalez R. A short cervix in women with preterm labor and intact membranes: a risk factor for microbial invasion of the amniotic cavity. Am J Obstet Gynecol 2005;192:678-689.
Improved prediction of pre-term delivery in patients with pre-term labor and intact membranes by a combination of fetal fibronectin and cervical ultrasound
Romero, Nien, Edwin
Vaginal fetal fibronectin and cervical ultrasound are widely used to assess the risk of pre-term delivery in the United States and Europe. A critical question is whether the combined use of these two tests improves the prediction of pre-term birth. We performed cervical sonography and determined fetal fibronectin in 215 patients admitted with pre-term uterine contractions (22 to 35 weeks) and cervical dilatation of less than or equal to 3 cm. Both tests performed comparably in the prediction of spontaneous pre-term delivery. However, when we added fetal fibronectin results to those of cervical length (less than 30 mm), we achieved a significant improvement in the prediction of pre-term delivery for women with a cervical length between 15 and 30 mm. Fibronectin determinations did not provide additional information in women with a cervix greater than 30 mm. Our study shows that fetal fibronectin adds prognostic information in a specific subgroup of patients. The results have implications for the care of women in pre-term labor.
Gomez R, Romero R, Medina L, Nien JK, Chaiworapongsa T, Carstens M, Gonzalez R, Espinoza J, Iams JD, Edwin S, Rojas I. Cervicovaginal fibronectin improves the prediction of preterm delivery based on sonographic cervical length in patients with preterm uterine contractions and intact membranes. Am J Obstet Gynecol 2005;192:350-359.
Role of complement activation in normal pregnancy and pregnancy complications
Romero, Nien, Hong,1 Edwin; in collaboration with Kim Y
Although pregnancy has been characterized as an anti-inflammatory state thought to be beneficial for the survival of the fetal semi-allograft, many investigators believe that pregnancy is characterized by “activation of the innate immune system” to compensate for an impaired adaptive immune response. Such activation of the innate immune response would protect the mother against infection. The complement system, a major component of innate immunity, has been recently implicated in the mechanisms of fetal loss and placental inflammation in the anti-phospholipid antibody syndrome. Inhibition of complement has been proposed as an absolute requirement for normal pregnancy. We conducted a series of studies to determine the behavior of complement split products or anaphylatoxins (C3a, C4a, and C5a) in normal pregnancy and pregnancy complications (pre-term labor, pyelonephritis, and unexplained pre-term birth). We found that (1) the median concentrations of C3a, C4a, and C5a are significantly higher in normal pregnant women than in non-pregnant women, suggesting that normal pregnancy is associated with complement activation; (2) the median plasma concentration of C5a in patients with fetal death was higher than that in normal pregnant women, implicating complement as a potential mechanism for fetal death in humans; (3) women in pre-term labor with intra-amniotic inflammation had higher concentrations of C5a than women in pre-term labor without microbial invasion of the amniotic cavity (however, spontaneous labor at term was associated with a lower median concentration of maternal plasma C5a); and (4) pyelonephritis during pregnancy (a condition frequently associated with acute respiratory distress syndrome [RDS]) was characterized by increased plasma concentrations of C5a but not other anaphylatoxins. The implication is that an excess of C5a can predispose pregnant women to develop acute RDS and multi-organ failure when affected by pyelonephritis, a common complication of pregnancy. This finding may have clinical implications given that blocking C5a may improve acute RDS in experimental sepsis.
Richani K, Romero R, Soto E, Espinoza J, Nien JK, Chaiworapongsa T, Refuerzo J, Blackwell S, Edwin SS, Santolaya-Forgas J, Mazor M. Unexplained intrauterine fetal death is accompanied by activation of complement. J Perinat Med 2005;33:296-305.
Richani K, Soto E, Romero R, Espinoza J, Chaiworapongsa T, Nien JK, Edwin S, Kim YM, Hong JS, Mazor M. Normal pregnancy is characterized by systemic activation of the complement system. J Matern Fetal Neonatal Med 2005;17:239-245.
Soto E, Richani K, Romero R, Espinoza J, Chaiworapongsa T, Nien JK, Edwin S, Kim YM, Hong JS, Goncalves L, Mazor M. Increased concentration of the complement split product C5a in acute pyelonephritis during pregnancy. J Matern Fetal Neonatal Med 2005;17:247-252.
Soto E, Romero R, Richani K, Espinoza J, Nien JK, Chaiworapongsa T, Santolaya-Forgas J, Edwin SS, Mazor M. Anaphylatoxins in preterm and term labor. J Perinat Med 2005;33:306-313.
Use of four-dimensional ultrasound to generate digital casts of the great vessels and venous return to the heart
Romero, Nien
Using four-dimensional ultrasonography with spatiotemporal image correlation (STIC) and inversion mode or B-flow imaging, we described a technique for reconstruction of the great vessels and venous return to the heart. Use of the techniques permitted visualization of “digital casts” similar to the silicone rubber casts of the cardiovascular system that can be obtained during postmortem examinations. It was possible to observe clearly spatial relationships between the outflow tracts, the connections of the great arteries to the ventricular chambers, and the connections between the venous system and atrial chambers. We applied the technique to the diagnosis of coarctation of the aorta, transposition of the great arteries, double outlet right ventricle, pulmonary stenosis, pulmonary atresia, and interruption of the inferior vena cava with azygous or hemiazygous continuation. In addition to improved visualization of the outflow tracts and venous return to the heart, the application of inversion mode to volume data sets of the four-chamber view allowed sharper delineation of the cardiac contours, atrioventricular valves, and ventricular septal defects than does two-dimensional ultrasound. We also used three-dimensional ultrasound with inversion mode to reconstruct fluid-filled structures such as the stomach, the ventricular system of the brain, and dilated ureters and renal pelvis in cases of urinary tract obstruction.
Espinoza J, Goncalves LF, Lee W, Mazor M, Romero R. A novel method to improve prenatal diagnosis of abnormal systemic venous connections using three- and four-dimensional ultrasonography and “inversion mode.” Ultrasound Obstet Gynecol 2005;25:428-434.
Goncalves LF, Espinoza J, Lee W, Nien JK, Hong JS, Santolaya-Forgas J, Mazor M, Romero R. A new approach to fetal echocardiography: digital casts of the fetal cardiac chambers and great vessels for detection of congenital heart disease. J Ultrasound Med 2005;24:415-424.
Use of three-dimensional ultrasound for individualized growth assessment of normal fetuses
Romero, Nien; in collaboration with Deter, Lee
We introduced fractional arm volume (AVol), a new soft tissue parameter that can be evaluated by three-dimensional ultrasound for longitudinal assessment of fetal growth. Using AVol, mid-arm circumference (ArmC), and humeral diaphysis length (HDL), we developed individualized growth standards based on Rossavik models. We prospectively studied 22 fetuses by two- and three-dimensional ultrasound. We constructed second-trimester models from the linear slopes of growth curves before 28 weeks of gestation and predicted normal third-trimester trajectories for each parameter. The Rossavik functions fit all parameter trajectories extremely well. The mean percent deviations between observed and predicted third-trimester HDL, ArmC, and AVol measurements were -0.1, 0.5, and 0.4 percent, respectively. The study demonstrated that individualized growth assessment can be performed by volumetric measurements of the fetal arm and that third-trimester fetal arm growth can be accurately predicted. AVol may allow early detection and improved monitoring of soft tissue abnormalities that occur in fetuses with growth disorders.
Lee W, Deter RL, McNie B, Goncalves LF, Espinoza J, Chaiworapongsa T, Balasubramaniam M, Romero R. The fetal arm: individualized growth assessment in normal pregnancies. J Ultrasound Med 2005;24:817-828.
Lee W, Goncalves LF, Espinoza J, Romero R. Inversion mode: a new volume analysis tool for 3-dimensional ultrasonography. J Ultrasound Med 2005;24:201-207.
Prevalence and clinical significance of amniotic fluid “sludge” in patients with pre-term labor and intact membranes
Romero, Nien; in collaboration with Espinoza, Goncalves
We examined the clinical significance of dense aggregates of particulate matter in the proximity of the cervical canal. The aggregates, called amniotic fluid “sludge,” are frequently observed by ultrasound in patients with pre-term labor and intact membranes. We determined the prevalence of amniotic fluid “sludge” in 84 patients with pre-term labor and intact membranes and in 298 uncomplicated pregnancies at term and found it to be 22.6 percent in those with pre-term labor and intact membranes and 1 percent in patients with uncomplicated term pregnancies. The rate of spontaneous pre-term delivery was higher in patients with amniotic fluid “sludge.” In addition, patients with amniotic fluid “sludge” had a higher frequency of positive amniotic fluid cultures (33.3 versus 2.5 percent) and histological chorioamnionitis (77.8 versus 19 percent), and their neonates were admitted to the NICU (64.3 versus 12.9 percent) or died more often (36.8 versus 4.6 percent) than neonates whose mothers had no amniotic fluid “sludge.”
Espinoza J, Goncalves LF, Romero R, Nien JK, Stites S, Kim YM, Hassan S, Gomez R, Yoon BH, Chaiworapongsa T, Lee W, Mazor M. The prevalence and clinical significance of amniotic fluid “sludge” in patients with preterm labor and intact membranes. Ultrasound Obstet Gynecol 2005;25:346-352.
1Joon-Seok Hong, MD, former Visiting Fellow
COLLABORATORS
Russell L. Deter, MD, Baylor College of Medicine. Houston, TX
Jimmy Espinoza, MD, Wayne State University School of Medicine, Detroit, MI
Ricardo Gomez, MD, Sotero del Rio Hospital, Puente Alto, Chile
Luis F Goncalves, MD, Wayne State University School of Medicine, Detroit, MI
Chong-Jai Kim, MD, PhD, Wayne State University School of Medicine, Detroit, MI
Yeon Mee Kim, MD, Wayne State University School of Medicine, Detroit, MI
Wesley Lee, MD, William Beaumont Hospital, Royal Oak, MI
Karina Richani, MD, Wayne State University School of Medicine, Detroit, MI
Eleazar Soto, MD, Wayne State University School of Medicine, Detroit, MI
For further information, contact warfiela@mail.nih.gov.