An early suspicion of intestinal volvulus allows the clinician to refer the patient to a tertiary center so to confirm the diagnosis and perform an appropriate follow-up in order to identify the proper time of delivery. The prognosis of the babies with prenatal intestinal volvulus depends on the length of the segment involved, on the level of intestinal obstruction, on the presence of meconium peritonitis and on the gestational age at birth. Our experience, according with the literature, suggests that ascites and absence of abdominal peristalsis are ultrasonographic signs that, in the third trimester of pregnancy, correctly lead to an immediate delivery intervention.

Nasal bone evaluation may improve the detection of trisomy 21 in the first trimester in an unselected obstetric population. Although numerically limited, our experience confirms that delayed nasal bone ossification (hypoplasia/absence of nasal bone) is rarely observed in chromosomally normal fetuses (1.4%). An appropriate training of operators is mandatory in order to achieve an acceptable performance.

The presence of fetal DNA in maternal plasma may represent a source of genetic material which can be obtained noninvasively. We wanted to assess whether fetal DNA is detectable in all pregnant women, to define the range and distribution of fetal DNA concentration at different gestational ages, to identify the optimal period to obtain a maternal blood sample yielding an adequate amount of fetal DNA for prenatal diagnosis, and to evaluate accuracy and predictive values of this approach. This information is crucial to develop safe and reliable non-invasive genetic testing in early pregnancy and monitoring of pregnancy complications in late gestation. Fetal DNA quantification in maternal plasma was carried out by real-time PCR on the SRY gene in male-bearing pregnancies to distinguish between maternal and fetal DNA. A cohort of 1,837 pregnant women was investigated. Fetal DNA could be detected from the sixth week and could be retrieved at any gestational week. No false-positive results were obtained in 163 women with previous embryo loss or previous male babies. Fetal DNA analysis performed blindly on a subset of 464 women displayed 99.4, 97.8 and 100% accuracy in fetal gender determination during the first, second, and third trimester of pregnancy, respectively. No SRY amplification was obtained in seven out of the 246 (2.8%) male-bearing pregnancies. Fetal DNA from maternal plasma seems to be an adequate and reliable source of genetic material for a noninvasive prenatal diagnostic approach.

Nasal bone absence is a marker for Down syndrome in the second trimester of pregnancy. Inclusion of nasal bone length into the second-trimester screening protocol could potentially obviate the false-negative cases from other screening tests. The measurement of nasal bone length in the second trimester seems to provide additional benefits beyond the assessment of the presence or absence of the nasal bone.

To assess the efficacy of the Doppler velocimetry of the uterine and umbilical arteries as a screening test for preeclampsia and fetal growth retardation, we studied 916low risk pregnancies. The SI D ratios of the uterine and umbilical arteries were obtained at 19 to 24 weeks and at 26 to 31 weeks of gestational age. Mean values, receiver operator curves, and the diagnostic accuracy of the tests were calculated for the following end-points: (1) pregnancy-induced hypertension, (2) low birth weight for gestational age, (3) small for gestational age with abnormal outcome, (4) pregnancy-induced hypertension needing preterm delivery. The prevalences for these out-ABBREVIATIONS S/0, Systolic-diastolic; PIH, Pregnancy-induced hypertension; SGA, Small for gestational age; IUGR, Intrauterine growth retardation Received November 19, 1993, from lstituto di Ginecologica e Ostetrica, Universita di Torino {T.T., S.B., M.B.); Clinica Ostetrica e Ginecologica, lstituto di Scienze Biomediche, Ospedale S. Paolo, Universita di Milano (E.F., B.B.); Clinica Ostetrica e Ginecologica, Universila Tor Vergata, Roma {G.R., H.V.); Clinica Ostetrica e Ginecologica, Cattedra di FJSiopatologica Prenatale, Universila di Bologna (S.g., G.L.P.); Clinica Ostetrica e Ginecologica, Universita di Siena (F.MS.); and Clinica Ostetrica e Ginecologica, Universita di Ancona {D.A., V.B.), Italy. Revised manuscript accepted for publication January 25, 1995.Address correspondence and reprint requests to Prof. Tull'ia Todros, lstituto dl Ginecologica e Ostetrica, Via Ventimiglia 3, 10126 Torino, Italy.This work was supported by the National Research Council (CNR)-Targeted Project "Prevention and Control Di, ease Factors," Subproject SP7 n.9100093PF41. comes were 3.4%, 4.6%, 1%, and 0.7%, respectively. The study was blinded. The umbilical and uterine artery SID ratios were significantly higher in the abnormal than in the normal outcome group. When uterine arteries were studied at 19 to 24 weeks, sensitivity was 59% in the detection of pregnancy-in· duced hypertension, 11% in the detection of small for gestational age fetuses, 33% in the detection of small for gestational age fetuses with abnormal outcome, and 83% in the detection of pregnancy-induced hypertension needing preterm delivery; the corresponding values for specificity were 69%, 94%, 94%, and 68%. At 26 to 31 weeks the sensitivity val· ues were respectively, 69%, 58%, 75%, and 100% and specificity values were 80%, 59%, 39%, and 79%. When umbilical arteries were studied at 19 to 24 weeks, sensitivity was 38% in the detection of pregnancy-induced hypertension, 46% in the detection of small for gestational age fetuses, 78% in the detection of small for gestational age fetuses with abnormal outcome, and 67% in the detection of pregnancy-induced hypertension needing preterm delivery. The corresponding values of specificity were 74% for all four groups. At 26 to 31 weeks the sensitivity values were 38%, 43%, 87%, and 67%, respectively, and specificity values were 80% for all four groups. We conclude that...