Mark Redman

Antimicrobial peptides in amniotic fluid: defensins, calprotectin and bacterial/permeability-increasing protein in patients with microbial invasion of the amniotic cavity, intra-amniotic inflammation, preterm labor and premature rupture of membranes

Objective: Neutrophil defensins (HNP 1-3), bactericidal/permeability-increasing protein (BPI) and calprotectin (MRP8/14) are antimicrobial peptides stored in leukocytes that act as effector molecules of the innate immune response. The purpose of this study was to determine whether parturition, premature rupture of the membranes (PROM) and microbial invasion of the amniotic cavity (MIAC) are associated with changes in amniotic fluid concentrations of these antimicrobial peptides. Study design: Amniotic fluid was retrieved by amniocentesis from 333 patients in the following groups: group 1, mid-trimester with a subsequent normal pregnancy outcome (n = 84); group 2, preterm labor and intact membranes without MIAC who delivered at term (n = 36), or prematurely (n = 52) and preterm labor with MIAC (n = 26); group 3, preterm PROM with (n = 26) and without (n = 26) MIAC; and group 4, term with intact membranes in the absence of MIAC, in labor (n = 52) and not in labor (n = 31). The concentrations of HNP 1-3, BPI and calprotectin in amniotic fluid were determined by specific and sensitive immunoassays. Placentae of patients in both preterm labor with intact membranes and preterm PROM groups who delivered within 72 h of amniocentesis were examined. Non-parametric statistics, receiver-operating characteristic (ROC) curves and Cox regression models were used for analysis. A p value of < 0.05 was considered statistically significant. Results: Intra-amniotic infection was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin in both women with preterm labor and intact membranes, and women with preterm PROM. Preterm PROM was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin. Preterm parturition was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin, while parturition at term was associated with a significant increase in amniotic fluid concentrations of immunoreactive HNP 1-3. Among patients with preterm labor and intact membranes, elevation of amniotic fluid HNP 1-3, BPI and calprotectin concentrations was associated with intra-amniotic inflammation, histological chorioamnionitis and a shorter interval to delivery. Conclusion: MIAC, preterm parturition and preterm PROM are associated with increased amniotic fluid concentrations of immunoreactive HNP 1-3, BPI and calprotectin. Moreover, elevated amniotic fluid concentrations of BPI, immunoreactive HNP 1-3 and calprotectin are associated with intra-amniotic inflammation, histological chorioamnionitis and shorter amniocentesis-to-delivery interval in patients presenting with preterm labor with intact membranes.

Vasa previa: clinical presentations, outcomes, and implications for management.

OBJECTIVE: To review experience with diagnosis, clinical associations, and outcomes of vasa previa in a single institution. METHODS: This was a retrospective review of all identified vasa previa cases from January 1 1990, to June 30, 2010. RESULTS: Sixty cases of vasa previa were identified (53 singletons, seven twins); 56 cases were diagnosed before delivery. An abnormal cord insertion or abnormal placental location was present in 55 cases. Missed diagnoses were attributed to technical and observer factors. Preterm bleeding was encountered in 25 (42%) case group participants. Seven case group participants required an emergent delivery, with significant neonatal morbidity and mortality. Twin pregnancies had a significantly earlier median age at delivery of 32 weeks of gestation compared with 35 weeks of gestations in singletons (P=.01). The seven twin pregnancies had a 28.6% emergent preterm delivery rate, whereas singletons had a 4.1% rate (P=.07). In 14 case group participants, the membranous fetal vessel was located in the lower uterus and not directly over the cervix. The vessel location was not related to the risk of emergent delivery. CONCLUSION: Transvaginal ultrasound scans of at-risk patients can identify most cases of vasa previa. Preterm bleeding does not usually require immediate delivery. The rate of emergent preterm delivery was low in singleton pregnancies. Twins were delivered, on average, 3 weeks earlier than singletons. LEVEL OF EVIDENCE: III

Relationship between the sonographic pattern of intrauterine growth restriction and acid-base status at the time of cordocentesis

Abstract Objective: To determine whether there is a difference in acid-base status at the time of cordocentesis between fetuses with symmetric and asymmetric intra- uterine growth restriction (IUGR). Study Design: Non-anomalous singleton fetuses with IUGR who underwent fetal blood sampling for rapid karyotype analysis from 1992–1995 were retrospectively identified. Cases with gestational age <24 weeks, abnormal karyotype, or evidence of congenital infection were excluded. Fetuses were divided into two groups based on Head Circumference/ Abdominal Circumference Ratio (HC/AC). The asymmetric-IUGR group had HC/AC ≥95% tile for GA, and the symmetric-IUGR group had HC/AC <95% tile. GA adjusted values of umbilical venous pH, pCO2, pO2, HCO3, hemoglobin and reticulocyte count were calculated by subtracting the mean values for GA from the observed and compared between groups. Results: Both symmetric-IUGR (n=7) and asymmetric-IUGR (n=9) had umbilical venous pH and pO2 levels lower than GA normative values. However, there were no differences between groups for any of the parameters studied. Conclusions: Fetuses with symmetric and asymmetric IUGR due to UPI display a similar degree of acid-base impairment.

Relationship between Meconium Staining and Amniotic Fluid Volume in Term Pregnancies

Objective: Our purpose was to evaluate the relationship between meconium-stained amniotic fluid (MEC-AF) and amniotic fluid volume (AFV) and their impact on the risk of cesarean delivery for fetal indications in term pregnancies. Methods: 1,655 live-born singleton gestations delivering at ≧37 weeks within 7 days of sonographic assessment of the amniotic fluid index (AFI) were studied. AFI was categorized as: oligohydramnios (≤5.0 cm); decreased (5.1–8.0 cm); normal (8.1–18.0 cm); increased (18.1–23.9 cm), and polyhydramnios (≧24.0 cm). Frequencies of MEC-AF for each AFV category were stratified by gestational age (GA) and rates of cesarean delivery for fetal indications compared between patients with clear amniotic fluid and those with MEC-AF. Stepwise logistic regression analyses were performed for determinants of MEC-AF and the need for cesarean delivery for fetal indications. Results: The frequency of MEC-AF at birth in term pregnancies was not related to AFV: oligohydramnios (16.7%); decreased (16.7%); normal (20.1%); increased (24.4%), and polyhydramnios (22.1%). The only factor associated with the occurrence of MEC-AF was increasing GA at delivery (p < 0.01). Both MEC-AF (p < 0.02) and decreasing neonatal ponderal index (p < 0.02) were independently associated with cesarean delivery for fetal distress. Conclusions: MEC-AF does not appear to be related to AFV in term pregnancies, and its presence increases the risk of cesarean delivery for fetal distress independent of AFV and neonatal ponderal index.

Severe pre-eclampsia remote from term: what to expect of expectant management

Objective: To describe the duration of expectant management and the indications for termination of expectant management of pregnancies complicated by severe pre-eclampsia remote from term. Study design: We identified pregnancies complicated by severe pre-eclampsia diagnosed between 24 weeks and 31 weeks 6 days at our institution in 1991-98. Pertinent clinical data were obtained from review of maternal and neonatal charts. Comparison of patients was based on the duration of time from admission to delivery: < 48 h (group 1), 48 h to 7 days (group 2), and ≥ 7 days (group 3). Results:A total of 142 women met all study criteria. Seventy-nine (55.6%) women were delivered within 48 h, 42 (29.6%) between 48 h and 7 days, and 21 (14.8%) at ≥ 7 days from diagnosis. Of group 1 patients (< 48 h), 59 (74.7%) were delivered for maternal indications while 20 (25.3%) were delivered for fetal indications. Of group 2 patients (48 h to 7 days), 35 (83.3%) were delivered for maternal indications while seven (16.7%) were delivered for fetal indications. Of group 3 patients (≥ 7 days), 16 (76.2%) were delivered for maternal indications while five (23.8%) were delivered for fetal indications. There were no significant differences in the indications for delivery based on the duration from admission to delivery. Conclusions: Despite an aggressive approach towards expectant management of preterm pregnancies complicated by severe pre-eclampsia, most patients were delivered within 48 h for maternal indications.

The effect of intrapartum magnesium sulfate therapy on fetal cardiac troponin I levels at delivery

Objective: To determine whether intrapartum magnesium sulfate (MgSO4) therapy for seizure prophylaxis in pre-eclampsia-eclampsia is associated with biochemical evidence of subacute fetal myocardial damage at delivery. Study design: Troponin I, a cardiac-specific protein used to detect myocardial injury, was measured from the umbilical vein at delivery in term pregnancies complicated by pre-eclampsia and uncomplicated control pregnancies. Women with pre-eclampsia received intravenous MgSO4 as a 6-g load followed by 2 g/hour until delivery. Clinical characteristics and fetal troponin levels were compared between groups. Results: There was no difference in troponin I concentrations between term patients with intrapartum MgSO4 therapy and controls who did not receive MgSO4 (median 0.86 ng/ml, range 0.72-1.10 vs. 0.89 ng/ml, range 0.68-1.50; p = 1.0). There was also no statistically significant difference in the number of patients with a troponin I level of ≥ 1.0 ng/ml between groups (30.8% (4/13) vs. 15.4% (4/26); p = 0.4). Conclusions: Our findings suggest that, in term fetuses that are not growth impaired, exposure to intrapartum MgSO4 is not associated with subacute myocardial injury.