Prediction of fetal lung immaturity using gestational age, patient characteristics and fetal lung maturity tests: a probabilistic approach

Objectives: The lecithin/sphingomyelin (L/S) ratio and the lamellar body count (LBC) can be used to predict respiratory distress syndrome (RDS). Design: We performed a retrospective cohort study among consecutive women who underwent amniotic fluid sampling for the assessment of fetal lung maturity. Logistic regression was used to construct models for the prediction of RDS in three gestational age categories, with models based on clinical characteristics only, clinical characteristics and the LBC, and on clinical characteristics and L/S ratio. Results: When amniotic fluid was collected <30 weeks, the specificity of the LBC was 30% and the sensitivity 100%. Addition of the L/S ratio increased the specifity to 60%, for a sensitivity of 100%. When amniocentesis was performed between 30 and 33 weeks, addition of the L/S ratio only marginally improved the performance of the LBC. Conclusions: At a gestational age <30 weeks, the L/S ratio has additional value over the LBC. Above 30 weeks of gestation, single use of the LBC seems sufficient.L. D. E. Wijnberger, M. de Kleine, H. A. M. Voorbij, B. Arabin, H. W. Bruinse, G. H. A. Visser, P. M. M. Bossuyt, B. W. J. Mo

Serum S100B levels after meningioma surgery: A comparison of two laboratory assays

<p>Abstract</p> <p>Background</p> <p>S100B protein is a potential biomarker of central nervous system insult. This study quantitatively compared two methods for assessing serum concentration of S100B.</p> <p>Methods</p> <p>A prospective, observational study performed in a single tertiary medical center. Included were fifty two consecutive adult patients undergoing surgery for meningioma that provided blood samples for determination of S100B concentrations. Eighty samples (40 pre-operative and 40 postoperative) were randomly selected for batch testing. Each sample was divided into two aliquots. These were analyzed by ELISA (Sangtec) and a commercial kit (Roche Elecsys^®) for S100B concentrations. Statistical analysis included regression modelling and Bland-Altman analysis.</p> <p>Results</p> <p>A parsimonious linear model best described the prediction of commercial kit values by those determined by ELISA (y = 0.045 + 0.277*x, x = ELISA value, R²= 0.732). ELISA measurements tended to be higher than commercial kit measurements. This discrepancy increased linearly with increasing S100B concentrations. At concentrations above 0.7 μg/L the paired measurements were consistently outside the limits of agreement in the Bland-Altman display. Similar to other studies that used alternative measurement methods, sex and age related differences in serum S100B levels were not detected using the Elecsys^®(p = 0.643 and 0.728 respectively).</p> <p>Conclusion</p> <p>Although a generally linear relationship exists between serum S100B concentrations measured by ELISA and a commercially available kit, ELISA values tended to be higher than commercial kit measurements particularly at concentrations over 0.7 μg/L, which are suggestive of brain injury. International standardization of commercial kits is required before the predictive validity of S100B for brain damage can be effectively assessed in clinical practice.</p

Effect of antenatal glucocorticoid therapy on arterial and venous blood flow velocity waveforms in severely growth-restricted fetuses

To study the effects of antenatal glucocorticoid (betamethasone) therapy on blood flow velocity waveform patterns in the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV) in severely intrauterine growth-restricted (IUGR) fetuses. Fifty-five severely IUGR fetuses at 24-34 weeks of gestation were included in the study. The effect of antenatal glucocorticoid administration on Doppler findings in the UA, MCA and DV was studied using two statistical approaches, namely paired sample analysis and multilevel analysis. There were no effects of betamethasone on the pulsatility index (PI) of the vessels studied. The only changes noticed during the 14 days of observation were a gradual decrease of PI in the MCA, an increase in the UA-PI/MCA-PI ratio and an increase in the DV-PI. These changes with time may be explained by a progressive and gradual deterioration of the fetal condition. Antenatal glucocorticoids (betamethasone) do not affect fetal Doppler waveform patterns of the UA, MCA and DV in severely IUGR fetuse

Comparison of vaginal and transabdominal collection of amniotic fluid for fetal lung maturity tests

BACKGROUNDS. The lecithin/spingomyelin (L/S) ratio and lamellar body count (LBC) are two tests that can be used to estimate the probability of the occurrence of respiratory distress syndrome (RDS). Our objective was to compare the prognostic capacity of the L/S ratio and the LBC in the prediction of RDS from amniotic fluid that was obtained either transabdominally or vaginally. METHODS.  Consecutive women undergoing amniotic fluid sampling for determination of fetal lung maturity were included. In case the membranes were ruptured, amniotic fluid was obtained vaginally. Otherwise, amniotic fluid was obtained by transabdominal amniocentesis. In each specimen, an L/S ratio and a LBC were measured. The predictive capacity of specimens that were obtained vaginally and transabdominally were compared by calculating the area under the receiver-operating-characteristic curve (AUC) analysis. RESULTS. In 260 patients amniotic fluid was collected transabominally, whereas in the other 67 patients there were ruptured membranes, and fluid was collected vaginally. RDS occurred in 25% of the patients without ruptured membranes, and in 34% of the patients with ruptured membranes. For the L/S ratio, the AUC was 0.56 (SE 0.09) for the vaginally collected specimens, and 0.93 (SE 0.02) in the specimens that were collected abdominally. For the LBC, the AUCs were 0.52 (SE 0.08) and 0.84 (SE 0.03), respectively. CONCLUSIONS.  Fetal lung maturity tests that are performed in vaginally obtained specimens in patients with ruptured membranes are of no use in the prediction of RDS.Lia D. E. Wijnberger, Madelijn De Kleine, Hieronymus A. M. Voorbij, Birgit Arabin, Henk Engel, Hein W. Bruinse, Gerard H. A. Visser, & Ben W. J. Mo

Supplement use and dietary sources of folate, vitamin D, and n-3 fatty acids during preconception : The GLIMP2 study

An adequate nutritional status during the preconception period is important, particularly for folate, vitamin D, and n-3 fatty acids (i.e., EPA+DHA). We aimed to determine supplement intake and the main dietary sources of folate, vitamin D, and EPA+DHA using the data of 66 Dutch women aged 18–40 years who wished to become pregnant. Additionally, associations of these intakes with their blood levels were examined. Dietary intake was assessed with a validated food frequency questionnaire, and supplement use with a structured questionnaire. 25-hydroxyvitamin D levels were determined in serum and folate and phospholipid EPA+DHA levels in plasma. Partial Spearman’s correlations, restricted cubic splines and trend analyses over tertiles of nutrient intakes were performed to examine intake-status associations. A large proportion of women did not meet the Dutch recommended intakes of folate (50%), vitamin D (67%), and EPA+DHA (52%). Vegetables were the main contributor to dietary folate intake (25%), oils and fats to dietary vitamin D intake (39%), and fish to dietary EPA+DHA intake (69%). Fourteen percent of the women had an inadequate folate status and 23% an inadequate vitamin D status. Supplemental folate intake, supplemental and dietary vitamin D intake and dietary EPA+DHA intake were significantly associated with their blood levels. In conclusion, even in our highly educated population, a large proportion did not achieve recommended folate, vitamin D and n-3 fatty acid intakes. Promotion of folate and vitamin D supplement use and fish consumption is needed to improve intakes and blood levels of these nutrients in women who wish to become pregnant.</p