Biomedical subjects

A D Christie

Publications and source records attributed to A D Christie.

17 recordsLinked to original sources

PubMed1985

Growth of total intrauterine, intra-amniotic and placental volume in normal singleton pregnancy measured by ultrasound.

The growth of total intrauterine, intra-amniotic and placental volume during the latter half of pregnancy was studied longitudinally with ultrasound in 115 healthy women with normal singleton pregnancies. A parallel planimetric area method was used. The range and distribution of normal values between 20 and 40 weeks was determined for a main study group of 103 primiparous women with which values from 12 parous women were compared. Total intrauterine volume increased from a median of 1006 ml to 4420 ml, intra-amniotic volume from 716 ml to 3406 ml and placental volume, calculated as the difference between total intrauterine and intra-amniotic volume, increased from 259 ml to 801 ml. Variation between individuals was wide at all stages of pregnancy. No significant difference was found between primiparous and parous women. Between successive 5-week periods from 20 to 40 weeks there was evidence that women tended to maintain their initial volume ranking. During the 30-35 week period, rate of growth of total intrauterine and intra-amniotic volume was somewhat faster than the near constant mean rate at other times, while the rate of growth of placental volume decreased after 30 weeks towards term.

Adolescent↗

PubMed1985

Efficacy of intrauterine volume, fetal abdominal area and biparietal diameter measurements with ultrasound in screening for small-for-dates babies.

The efficacy of total intrauterine, intra-amniotic and placental volume measurements with ultrasound in screening for low birthweight (less than or equal to 10th and less than or equal to 3rd centile) was compared prospectively with fetal biparietal diameter and abdominal area measurements at 32 and 36 weeks gestation in an unselected population of 362 women. In all of them the gestation was dated by ultrasound in the first half of pregnancy. Reference values were from a separate normal population studied previously. Total intrauterine volume showed the highest sensitivity in predicting babies weighing less than or equal to 10th centile (58% at 32 weeks and 62% at 36 weeks) and those weighing less than or equal to 3rd centile (78% at 32 weeks and 83% at 36 weeks). A higher number of false-positive tests resulted in a lower predictive value of a positive test (mean 34% for babies weighing less than or equal to 10th centile) than that found for abdominal area (mean 54%). Abdominal measurements selected a smaller 'at risk' group. Biparietal diameter, intra-amniotic and placental volume measurements had inferior predictive capability than total intrauterine volume and abdominal area. For screening purposes abdominal area measurements are presently more suitable than intrauterine volume. The higher sensitivity of intrauterine volume, particularly in early third trimester, is an advantage that requires further investigation with reference to intrauterine growth retardation.

Adult↗

PubMed1985

Intrauterine volume, fetal abdominal area and biparietal diameter measurements with ultrasound in the prediction of small-for-dates babies in a high-risk obstetric population.

The value of fetal biparietal diameter and abdominal area, total intrauterine, intra-amniotic and placental volume measurements for predicting small-for-dates babies in a high-risk obstetric population was investigated in 130 women. A parallel planimetric area method was used to measure volume. The commonest risk factors were suspected intrauterine growth-retardation, hypertensive complications and previous poor obstetric history. The prevalence of birthweight at and below the 10th or 3rd centiles was 30 and 16% respectively. Fetal abdominal area and total intrauterine volume measurements had the highest and comparable sensitivity, specificity and positive predictive value in the detection of infants with birthweights of less than or equal to 10th and less than or equal to 3rd centiles. While these measurements are of use in consolidating the clinical diagnosis of small-for-dates fetuses (growth retardation), high false positive rates (10% and 16-17% for birthweights less than or equal to 10th centile, and less than or equal to 3rd centile respectively) make further discriminatory tests necessary for part of the population.

Adolescent↗

PubMed1984

In-vivo accuracy of ultrasound measurements of intrauterine volume in pregnancy.

The accuracy of ultrasonic measurements of intra-amniotic volume using a parallel planimetric area method was assessed in 18 women by comparison against different measures of the same volume space. In nine patients undergoing second-trimester termination of pregnancy amniotic fluid volume was measured using a dye dilution method and fetal volume was measured by either water displacement or calculated from fetal weight. The estimated intra-amniotic volume by this method was not significantly different from the ultrasonic measurement. In one patient who had a hysterotomy, fetal and amniotic fluid volumes showed a difference of 1.01% between ultrasonically-measured and actual intra-amniotic volume. In eight patients studied in the third trimester the mean difference between ultrasonic and estimated intra-amniotic volume at delivery was 6.2%.

Amnion↗

PubMed1983