Birthweight percentiles by gestational age in Kuwait.

Our aim is develop a curve for singleton birthweight based on accurately calculated gestational age. A retrospective analysis of all singleton live births from 22-44 completed weeks of gestation during the period from September 1998 to December 2000 in the two largest birth birth centers in Kuwait was conducted. Neonates with major congenital anomalies and those with unrecorded gestational age were excluded from the study population. Total population and gender-specific birthweight percentiles according to gestational age were developed after smoothening of growth curves. A total of 35768 births were included in the development of the birthweight curve. Percentiles of birthweight for all population and by gender are presented. There was significant difference in birthweight among different ethnic groups in this population. At term, 9.8% of births are smaller than the 10th percentile and 10.0% are larger than the 90th percentile. Plotting birthweight in our population on percentile curves derived from the United States or United Kingdom would generally overestimate small for gestational age newborns and underestimate large for gestational age newborns. We conclude that the diagnosis of clinically significant birthweight abnormalities depends on the fetal growth curve used. A population specific curve of fetal growth dated by ultrasonography would provide a reliable reference for birthweight distribution.

Ethnic variations in birthweight percentiles in Kuwait.

The objectives of this retrospective study were to assess the effect of ethnicity on birthweight percentiles and to compare ethnic-specific percentiles with other references. Analysis was made of 35 768 singleton live births from 22 to 44 completed weeks of gestation at two major obstetric hospitals in Kuwait, after exclusion of data with inaccurate gestational age, major congenital abnormalities, stillbirths, and outlying birthweights. The population included four major ethnic groups: Gulf Arabs, Mediterranean Arabs, Egyptians, and a group combining Indians and Southeast Asians. Total population and ethnic-specific smoothed birthweight percentiles according to gestational age were developed. Indians-Asians had the smallest birthweights, the highest prevalence of small-for-gestational-age (SGA) birthweights and the lowest prevalence of large-for-gestational-age (LGA) birthweights. On the contrary, Egyptians had the largest birthweights, the lowest prevalence of SGA birthweights and the highest prevalence of LGA birthweights. Plotting our birthweights on a reference from Canada resulted in a low prediction rate for SGA and a low sensitivity in identifying LGA of all ethnic groups. We conclude that interpretation of fetal growth and birthweight should involve locally derived and ethnically specific percentiles based on accurately calculated gestational age.

Prediction of fetal anemia by middle cerebral artery peak systolic velocity in pregnancies complicated by rhesus isoimmunization.

OBJECTIVES: To study the correlation of peak systolic velocity in the middle cerebral artery with hemoglobin concentration in fetuses at risk of anemia due to Rhesus isoimmunization. DESIGN: Peak systolic velocity of middle cerebral artery (MCA-PSV) was measured before 66 cordocentesis procedures in 20 isoimmunized fetuses. Reference values were derived from a study of 300 control fetuses. MCA-PSV values and hemoglobin concentrations were expressed as multiples of the median (MoM) for gestational age. The following hemoglobin concentration MoM thresholds defined degrees of anemia: mild, between 0.83 and 0.65; moderate, between 0.64 and 0.55; and severe, less than 0.55. Regression analysis was performed and receiver-operator-characteristic curves were constructed to determine the diagnostic accuracy of different thresholds of MCA-PSV for the prediction of moderate to severe anemia, either at the initial or repeat cordocentesis procedures. RESULTS: The mean (+/-SD) gestational age at cordocentesis was 28.5+/-4.6 weeks. Moderate to severe anemia was observed on 29 (44%) and hydrops on 27 (41%) occasions. MCA-PSV correlated weakly with hemoglobin concentrations. At threshold values 1.50 MoM, the sensitivity, specificity, and negative predictive value for moderate to severe anemia were 9.0, 100, and 48.0% at the initial cordocentesis procedures, and 44.0, 96.0, and 73.0% at repeat cordocentesis procedures, respectively. CONCLUSIONS: Although MCA-PSV is highly specific, negative values do not rule out fetal anemia. Further research is required before it can be recommended in clinical practice.

Treatment of ectopic pregnancy with a single intramuscular dose of methotrexate.

This study evaluates the outcome of unruptured ectopic pregnancies treated with single-dose intramuscular methotrexate injection. There were 77 women with unruptured non-laparoscopically diagnosed ectopic pregnancies who were prospectively followed after receiving a single dose of 50 mg/m2 intramuscular methotrexate. Diagnosis required transvaginal ultrasound and serial quantification of beta subunit of human chorionic gonadotropin (betahCG). A repeat dose was given if the weekly drop of betahCG was less than 30%. Therapy was considered successful if complete resolution of betahCG to a level below 25 IU/L was achieved without surgical intervention. Treatment in 73 (95%) cases was successful. The mean pre-treatment level of betahCG was 2592 +/- 3771 IU/L (177-15000 IU/L), the mean diameter of ectopic mass was 2.4 +/- 1.0 cm (1.7-3.5 cm). The average resolution period was 3.2 +/- 1.0 weeks (1-6 weeks) and this significantly correlated with the pre-treatment betahCG level. With strict criteria of inclusion and follow-up, single-dose intramuscular methotrexate is a successful method for the treatment of selected cases of ectopic pregnancy.

Transport of neutral amino acids by human erythrocytes.

The transport of several neutral amino acids by human erythrocytes in vitro was studied. The measurements made included steady-state distributions, kinetics of initial rates of uptake, effects of monovalent cations and anions, general mutual inhibitory interactions, kinetics of inhibitions, effluxes, ability to produce accelerative exchange diffusion, and the inhibitory action of the thiol reagent N-ethylmaleimide. The results are interpreted as showing that the human erythrocyte membrane possesses several distinct transport systems for these amino acids, including one Na+-dependent system and one dependent on both Na+ and a suitable anion, that are qualitatively similar to those systems previously described in pigeon erythrocytes and mammalian reticulocytes. Quantitatively, however, the systems differ among the different kinds of red cell and a major difference lies in their abilities to produce accelerative exchange diffusion.