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Biomedical subjects

J P Neilson

Publications and source records attributed to J P Neilson.

At least 73 records · Page 4Linked to original sources
PubMed1989

Prediction of the small for gestational age twin fetus by Doppler umbilical artery waveform analysis.

In 89 consecutive twin pregnancies, monthly Doppler ultrasound measurements were made of the umbilical artery blood flow velocity waveforms of each fetus. In total, 453 Doppler studies were performed. Of the 178 infants, 32 were small for gestational age (SGA); only 24 of the 82 SGA Doppler studies were abnormal, giving an overall sensitivity of the test in the prediction of the SGA fetus of 29% and a positive predictive value of 34%. Furthermore, neither the sensitivities nor the positive predictive values were above 50% in any of the gestational-age intervals individually studied. We conclude that Doppler study of umbilical artery flow velocities is not of much value in the prediction of SGA infants in twin pregnancies, although persistently absent end-diastolic velocities were associated with poor outcome.

Blood Flow Velocity↗
PubMed1988

Fetal growth in twin pregnancies.

In 65 consecutive twin pregnancies, 722 measurement of fetal abdominal circumference have been obtained with ultrasound. Zygosity was established after delivery in 85% of the pregnancies. There was no difference in mean abdominal circumference measurements between monozygotic and dizygotic pregnancies. In both groups, the pattern of growth was linear throughout pregnancy in contrast to that predicted by birthweight for gestational age charts. It is suggested that increasing trunk flexion, in later twin pregnancy, may distort accurate abdominal circumference measurement.

Birth Weight↗
PubMed1988

Tape measurement of symphysis-fundal height in twin pregnancies.

We hypothesized that tape measurement of symphysis-fundal height could be useful in detecting multiple pregnancies, and in such cases in predicting preterm labour and identifying small-for-gestational-age (SGA) fetuses. Although mean fundal height is substantially greater in twin than singleton pregnancies, the value of the technique to detect multiple pregnancies may be limited because combined birth-weight is less and the frequency of SGA fetuses is greater in undiagnosed than in diagnosed twin pregnancies. We found no evidence that the measured fundal height is greater in pregnancies going on to preterm delivery, and we suggest that the commonly accepted theory that the high rate of preterm labour in twin pregnancies results simply from uterine overdistension be reappraised. Nevertheless, fundal height measurement was of value in identifying pregnancies in which both babies were SGA and is therefore recommended as a simple, inexpensive and non-invasive technique.

Anthropometry↗
PubMed1988

Preterm labor in twin pregnancies: prediction by cervical assessment.

Patients attending a twin pregnancy antenatal clinic underwent cervical palpation at each visit to calculate a cervical score by subtracting dilatation from length. Prediction of the onset of labor by cervical assessment was studied in 223 already parous women with twin pregnancies who ultimately labored spontaneously. The lower the score, the shorter was the mean time until delivery, although there existed a subgroup of patients who had ripe cervices for several weeks before the onset of labor. The cervical score itself appeared to give better prediction of labor than did changes in the score. Cervical assessment identified a group of twin pregnancies at especially high risk of preterm labor, in that 76% of patients with a score of -2 or less at or before 34 weeks delivered preterm. There was no evidence that labor was precipitated by vaginal examination, although this requires further study.

Cervix Uteri↗
PubMed1984

Screening for small for dates fetuses: a controlled trial.

In the hope of reducing perinatal risks associated with retardation of intrauterine growth a previously described two stage ultrasound screening schedule was evaluated by a controlled trial in 877 women with low risk single pregnancies. The two stages of ultrasound examination were an assessment of gestational age during early pregnancy followed by measurement of length from crown to rump and area of trunk at between 34 and 36 weeks' gestation. The product of crown to rump length and trunk area was calculated. The sensitivity of this schedule in identifying in advance 94% of babies who were small for dates at birth, with 90% specificity, and the speed and simplicity of measurement confirmed the accuracy and feasibility of two stage ultrasonography as a screening procedure. The controlled trial did not, however, show any benefit from its routine application in these low risk pregnancies.

Adult↗
PubMed1984

Product of fetal crown-rump length and trunk area: ultrasound measurement in high-risk pregnancies.

Calculation of the product of crown-rump length and trunk area (CRL x TA), as measured by ultrasound between 34 and 36 weeks and combined with accurate assessment of gestational age in early pregnancy, was previously shown to be highly effective in detecting the small-for-dates fetus in a largely unselected series of patients. To assess the value of this two-stage schedule in high-risk pregnancies, 202 patients with singleton pregnancies at risk of fetal growth retardation were studied. Of the 53 babies that were small-for-dates at birth, 49 (92%) were identified in advance by CRL x TA measurement. In contrast to previous findings, measurement of trunk area (TA) alone was similarly effective, identifying in advance 48 (91%) of these small-for-dates babies.

Anthropometry↗
PubMed1982

Ultrasonic evaluation of twin pregnancies associated with raised serum alpha-fetoprotein levels.

Five cases of twin pregnancy associated with elevated maternal serum alpha-fetoprotein levels are presented. In each instance an abnormality was detected by ultrasound examination--in four cases this represented anomalous development of one or both fetuses: discordant anencephaly; a monozygotic heterokaryotypic twin pregnancy with coexistent Turner's syndrome and intrauterine death; concordant body-stalk syndrome; and fetal exomphalos together with an acardiac monster. In the remaining case, there had been an intrauterine death of one of the twins. Ultrasound examination proved valuable in all instances; three pregnancies were terminated and single healthy infants were delivered from each of the other two pregnancies.

Congenital Abnormalities↗
PubMed1982

Detection of the small-for-gestational age twin fetus by a two-stage ultrasound examination schedule.

Serial ultrasonic measurement of the biparietal diameter is an unsatisfactory means of detecting the small-for-gestational age (SGA) fetus in twin pregnancies. A new two-stage ultrasound examination schedule, highly effective in detecting the SGA singleton fetus, has been evaluated prospectively in 31 twin pregnancies. The schedule comprises ultrasonic assessment of gestational age in early pregnancy, followed by measurement of the product of the crown-rump length and trunk area of both fetuses at 34-36 weeks. All Nineteen SGA twin fetuses were detected using this schedule; the technique offers several other advantages over serial biparietal cephalometry.

Female↗
PubMed1982

Detection by ultrasound of abnormality in twin pregnancies during the second trimester.

Five cases of abnormality in twin pregnancies, detected by ultrasound examination during the second trimester, are reported. In four pregnancies there was a fetal malformation: discordant anencephaly, a monozygotic, heterokaryotypic twin pregnancy with coexistant Turner's syndrome and intrauterine death, concordant body stalk syndrome, and a dicephalus monster. In the other pregnancy one fetus dies in utero to become a fetus papyraceous. Four of the pregnancies were associated with raised levels of maternal serum alpha-fetoprotein, by singleton standards. Ultrasound examination proved of value in each case. Three pregnancies were terminated.

Adult↗
PubMed1981

Detection of the small-for-dates twin fetus by ultrasound.

As methods for identifying the small-for-dates fetus in twin pregnancies, serial ultrasonic cephalometry and a new two-stage ultrasound examination schedule have been evaluated and compared. Serial cephalometry is associated with technical and interpretative problems, and only 24 (56 per cent) of 43 small-for-dates fetuses in 66 retrospectively studied twin pregnancies showed detectably abnormal biparietal diameter growth. The two-stage schedule comprises an accurate assessment of gestational age in early pregnancy, and determination of the product of the crown-rump length and trunk area at 34 to 36 weeks; this identified all 15 small-for-dates fetuses in 21 prospectively studied twin pregnancies, and the method offers several other advantages over serial cephalometry.

Anthropometry↗