Prediction Of Gestational Age Research Articles

Preconception Cardiovascular Risk Factors and Pregnancy Outcome

Pregnancy-related cardiovascular conditions are associated with both poorer pregnancy outcomes and cardiovascular disease later in life. Little is known about the relationship between preconception cardiovascular risk factor levels and pregnancy complications. Data from the Cardiovascular Risk in Young Finns Study were linked with birth registry data for 1142 primiparous women. Age-standardized levels of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, triglycerides, blood pressure, insulin, and glucose from the study visit prior to last menstrual period were calculated. These factors were examined as predictors of gestational age, preterm birth (<37 weeks), birthweight, low birthweight (<2500 g), small-for-gestational-age (weight <10th percentile for gestational age), hypertensive disorders of pregnancy, and gestational diabetes, using linear and Poisson regression with adjustment for age, body mass index, smoking, and socioeconomic status. Higher triglycerides were associated with a higher risk of hypertensive disorders (adjusted risk ratio [aRR] = 1.42 [95% confidence interval (CI) = 0.90-2.23]), preeclampsia (1.70 [1.08-2.65]), and gestational diabetes (1.68 [1.25-2.25]). After removing women with pregnancy complications (n = 30), the estimated aRR for the association between systolic blood pressure and preterm birth was 1.23 (95% CI = 0.99-1.54); for HDL-c and low birthweight, 0.97 (0.73-1.28); for diastolic blood pressure and small-for-gestational-age, 0.98 (0.81-1.20); and for systolic blood pressure and small-for-gestational-age, 1.18 (0.97-1.45). High lipid levels before pregnancy predict an increased risk of preeclampsia and gestational diabetes. Reported associations between these pregnancy complications and later cardiovascular disease of the mother are probably explained, at least in part, by maternal conditions that precede pregnancy. Interventions to improve cardiovascular health before pregnancy may reduce risk of pregnancy complications.

Ultrasonic attenuation estimation of the pregnant cervix: a preliminary report

Estimates of ultrasonic attenuation (the loss of energy as an ultrasonic wave propagates through tissue) have been used to evaluate the structure and function of tissues in health and disease. The purpose of this research was to develop a method to estimate ultrasonic cervical attenuation during human pregnancy using a clinical ultrasound system. Forty women underwent a cervical scan once during pregnancy with the Zonare z.one clinical ultrasound system using a 4-9-MHz endovaginal transducer. This ultrasound system provides access to radiofrequency (RF) image data for processing and analysis. In addition, a scan of a tissue-mimicking phantom with a known attenuation coefficient was acquired and used as a reference. The same settings and transducer used in the clinical scan were used in the reference scan. Digital data of the beam-formed image were saved in Digital Imaging and Communications in Medicine (DICOM) format on a flash drive and converted to RF data on a personal computer using a Matlab program supplied by Zonare. Attenuation estimates were obtained using an algorithm that was independently validated using tissue-mimicking ultrasonic phantoms. RF data were acquired and analyzed to estimate attenuation of the human pregnant cervix. Regression analysis revealed that attenuation was: a predictor of the interval from ultrasound examination to delivery (beta = 0.43, P = 0.01); not a predictor of gestational age at time of examination (beta = - 0.23, P = 0.15); and not a predictor of cervical length (beta = 0.077, P = 0.65). Ultrasonic attenuation estimates have the potential to be an early and objective non-invasive method to detect interval between examination and delivery. We hypothesize that a larger sample size and a longitudinal study design will be needed to detect gestational age-associated changes in cervical attenuation.

Effects of Antenatal Depression and Antidepressant Treatment on Gestational Age at Birth and Risk of Preterm Birth

The authors evaluated the effects of prenatal antidepressant exposure and maternal depression on infant gestational age at birth and risk of preterm birth. Ninety women were followed in a prospective, naturalistic design through pregnancy with monthly assessments of symptoms of depression and anxiety using the Structured Clinical Interview for DSM-IV mood module for depression, the Hamilton Depression Rating Scale, the Beck Depression Inventory, and the Perceived Stress Scale. Participants included 49 women with major depressive disorder who were treated with antidepressants during pregnancy (group 1), 22 women with major depressive disorder who were either not treated with antidepressants or had limited exposure to them during pregnancy (group 2), and 19 healthy comparison subjects (group 3). The primary outcome variables were the infants' gestational age at birth, birth weight, 1- and 5-minute Apgar scores, and admission to the special care nursery. Groups 1, 2, and 3 differed significantly in gestational age at birth (38.5 weeks, 39.4 weeks, 39.7 weeks, respectively), rates of preterm birth (14.3%, 0%, 5.3%, respectively), and rates of admission to the special care nursery (21%, 9%, 0%, respectively). Birth weight and Apgar scores did not differ significantly between groups. Mild to moderate depression during pregnancy did not affect outcome measures. Prenatal antidepressant use was associated with lower gestational age at birth and an increased risk of preterm birth. Presence of depressive symptoms was not associated with this risk. These results suggest that medication status, rather than depression, is a predictor of gestational age at birth.

DIAGNOSING PREGNANCY, IN UTERO LITTER SIZE, AND FETAL GROWTH WITH ULTRASOUND IN WILD, FREE-RANGING WOLVES

We document the accuracy, efficacy, and safety of ultrasound in estimating reproductive characteristics of gray wolves(Canislupus)incentralAlaska.Weexamined68adultfemalewolveswithultrasoundduringlateMarchand early April to diagnose pregnancy and litter size. Seventy-two percent were pregnant. We compared ultrasound diagnoses with postmortem embryo or placental scar counts in 14 females that died within 10 months of being examinedbyultrasound;allultrasoundandpostmortemexaminationsagreedinthediagnosesofpregnancy.Among 12 pregnant females, 6 agreed exactly in fetal count, 11 were within 1 fetus, and all were within 2 fetuses. In the postmortem sample we detected a decline in average placental scar color density between mid-September and midFebruary. Radiocollared females were monitored from the air to estimate denning rates. Distance from the den declined as parturition approached, but few females localized near dens before parturition. Among 46 pregnant femalesdiagnosedbyultrasound,80.4%enteredandremainedatdens,15.2%failedtoenterdens,and4.4%denned but abandoned the den within 1 week. None of the females diagnosed as nonpregnant entered dens. We present modelsoffetalgrowthfromultrasoundmeasurementsofembryonicvesiclediameters(EVD)orcrown‐rumplength (CRL) of in utero fetuses. CRL was a better predictor of gestational age (r 2 ¼ 0.92) than was EVD (r 2 ¼ 0.79). We found no evidence that capture of females during the 2nd trimester of pregnancy affected denning or productivity.

Fetal trans-cerebellar diameter measurement: an accurate predictor of gestational age in late gestation

Fetal trans-cerebellar diameter measurement: an accurate predictor of gestational age in late gestation

Evaluation of gestational age based on ultrasound fetal growth measurements.

Monitoring fetal growth and assessing its predictors have important place in antenatal care management. Accurate prediction of gestational age (GA) and birth weight (BW) is clinically important. Standard growth curve chosen should be evaluated to see if it satisfies the criteria for a valid assesment. In this paper, for the purpose of contributing to develop national standards and to evaluate Hadlock's standard data pertaining to 1411 fetuses were examined. Of 1411 normally growing fetuses, one measurement for AC, BPD and FL was taken by ultrasound. GA was assessed via menstrual history which is also confirmed by ultrasonography. Several variables, AC, BPD, FL, FL/AC, BPD/FL and dependent variables (GA & BW) were modelled mathematically. Percentile values, correlation coefficients were calculated and well functioning regression equations were produced for the fetal growth evaluation. Simple correlation model re-confirmed that AC, BPD and FL were well predictors of GA. Via modelling by multivariate regression analysis (adj. R2=937), GA=4.945 (95% CI: 4.661- 5.654) + .606 AC + .105 BPD + .286 FL can be estimated. It couldn't be possible establishing an appropriate equation for prediction of BW with current data. Our study is intended to draw an attention on requirement of national standards although Hadlock's standard growth curve may evaluate fetal development accurately. Forming comprehensive cohort group is under our consideration. The equation we developed (shown in the results), might be a working contribution.

ARTERIAL SUPPLY OF THE HUMAN FETAL TESTIS DURING ITS MIGRATION

Irrespective of the surgical technique chosen to treat high undescended testis, preservation of an adequate arterial supply for the testis is crucial for successful orchiopexy with maintenance of normal testicular size and texture. To provide an anatomical background for such a procedure, we performed a systematic study on the number and origin of arteries supplying the fetal testis during its migration from the abdomen to the scrotum. We studied bilaterally 64 testes from 32 fresh human fetuses 13 to 33 weeks after conception. The fetuses were injected through the thoracic aorta with a microvascular silicone rubber red resin to fill in the arterial tree, thereby enabling identification and dissection of all arteries supplying the testes. Of the 64 testes 3 arteries (testicular, deferential and cremasteric) were found in 46 (71.9%), 2 (testicular and deferential) in 15 (23.4%) and 4 in 3 (4.7%). The fetal testis is always supplied by at least 2 arteries (testicular and deferential arteries) and by 3 or 4 arteries in nearly 80% of the cases.

Metatarsal growth during the second trimester: a predictor of gestational age?

Metatarsal growth was studied in 780 human fetal metatarsal bones, crown-rump length ranging from 120 to 260 mm and gestational age ranging from 14 to 23 wk postconception. Total length, diaphyseal length and diameter were measured and statistical analysis performed. Means and standard deviations for each measurement were calculated at 1 wk intervals. These data were correlated with crown-rump length and gestational age and an equation was constructed in an attempt to predict gestational age.

How accurate is fetal biometry in the assessment of fetal age?

OBJECTIVE: The purpose of the study was to assess the accuracy of fetal biometry in the midtrimester of pregnancy in the assignment of fetal age. STUDY DESIGN: A total of 152 singleton, 67 twin, and 19 triplet gestations resulting from in vitro fertilization with ultrasonographic fetal biometry from 14 to 22 weeks made up the study population. A gestational age prediction equation was derived from singletons with the use of stepwise linear regression. This equation was compared with 38 previously published equations and then applied to the twin and triplet populations. RESULTS: Head circumference was the best predictor of gestational age (random error [SD] 3.77 days). Addition of abdominal circumference and femur length to head circumference improved the accuracy of the dating equation (random error 3.35 days). Most dating formulas had systematic errors of <1 week. The systematic error was –0.32 day for averaging the singleton-based predictions for twins and –1.26 days for triplets. CONCLUSIONS: Gestational age assessment with the use of fetal biometry from 14 to 22 weeks is accurate for singleton, twin, and triplet gestations. (Am J Obstet Gynecol 1998;178:678-87.)

Ultrasound measurement of fetal growth in Macaca nemestrina.

Longitudinal ultrasound data were collected for 18 structures in 37 pigtailed macaque (Macaca nemestrina) fetuses to 1) generate standards of normal fetal growth, 2) measure operator reliability, 3) assess the accuracy of linear and nonlinear regression models to estimate gestational age and dates of delivery, and 4) evaluate the portability of equations and absolute values derived from data at one facility (Seattle) to describe independently collected data on the same species at another facility (Medical Lake Breeding Colony). Femur length, biparietal diameter, and head area were found to be the best predictors of gestational age, as judged by maximum "explained" variance (R2) with minimum error estimates. Days to delivery could not be adequately predicted by any single fetal growth parameter or by the best combination of parameters. Operator reliability was very good: error was ⩽5% over all parameters studied. Although the form of growth curves from each facility was generally the same, variability was much greater for most parameters at Medical Lake, and both femur and humerus lengths were overestimated relative to the Seattle data. The same result was obtained for femur length when Seattle data on pigtailed macaques were compared with published data on rhesus macaques. We believe that these differences in facilities and populations may be due to the practices of the ultrasound operators. We suggest that portability of regression coefficients and absolute values for structures at a given gestational age can be accomplished only if operators are trained to use the same standard methods and receive periodic reliability checks. © 1995 Wiley-Liss, Inc.

Is urinary microalbumin excretion, a predictor of gestational age at delivery and birth weight?

Is urinary microalbumin excretion, a predictor of gestational age at delivery and birth weight?

172 The Fetal Transverse Cerebellar Diameter as a Predictor of Gestational Age in the Third Trimester

172 The Fetal Transverse Cerebellar Diameter as a Predictor of Gestational Age in the Third Trimester

Fetal Metatarsal Length: An Accurate Predictor of Gestational Age and Weight in the Ovine Fetus

Accurate assessment of gestational age and fetal weight in the pregnant ewe is important in both acute and longitudinal perinatal studies. We describe two morphometric methods based on the length of the fetal metatarsal bone. These measurements can be made intraoperatively or at postmortem. Metatarsal bone lengths can be used to better predict gestational age and fetal weight than previously described methods.

Transverse cerebellar diameter in twin gestations

OBJECTIVE: The purpose of this study was to evaluate the significance of transverse cerebellar diameter measurements in twin pregnancies. STUDY DESIGN: A prospective, cross-sectional ultrasonographic study was done on 329 normal singleton fetuses and 47 normal twin pairs. Fetal biometric measurements including biparietal diameter, head circumference, abdominal circumference, femur length, and transverse cerebellar diameter were compared between concordant ( n = 13) and discordant ( n = 11) twins. sp RESULTS: (1) There was no significant difference in transverse cerebellar diameter measurements between normal singleton and twin gestations. (2) There was no significant difference in transverse cerebellar diameter measurements in each twin pair. (3) Transverse cerebellar diameter was unaffected by the chorionicity or discordancy. (4) Predicted gestational age by transverse cerebellar diameter nomogram for singletons provided satisfactory correlation for twins. CONCLUSION: Transverse cerebellar diameter may be a useful predictor of gestational age and may be independent of discordant growth in twins. (Am J Obstet Gynecol 1992;167:1004-8.)

Fetal aortic and pulmonary artery diameters: sonographic measurements in growth-retarded fetuses.

The small size of the head and abdomen in a growth-retarded fetus may lead to inaccurate estimates of gestational age. Therefore, we conducted a study to assess the diameters of the aortic root and pulmonary artery in such fetuses. During the study period, we measured these great vessel diameters at the level of the semilunar valves on all third-trimester obstetric sonograms in which intrauterine growth retardation was suspected. Cases were included in the study if delivery occurred within 1 week of the scan and if growth retardation was confirmed after birth. The study population consisted of 75 growth-retarded fetuses. We compared the relationships between great vessel diameters and gestational age in this study population with norms previously established in our laboratory in 403 normal fetuses. In a similar fashion, we compared the relationships between great vessel diameters and biparietal diameter in our study population with previously established norms. We found no significant difference between great vessel diameters in growth-retarded fetuses and those in normal fetuses of the same gestational age (p greater than .45 for aorta; p greater than .40 for pulmonary artery). In contrast, aortic root diameter was larger in relation to biparietal diameter in growth-retarded fetuses than it was in normal fetuses (p less than .05), and there was a tendency toward the same result for the pulmonary artery. We conclude that the diameters of the aorta and pulmonary artery remain normal in most cases of intrauterine growth retardation. The aorta and pulmonary artery may be useful predictors of gestational age when growth retardation is suspected.

Fetal Foot Length as a Predictor of Gestational Age

Fetal Foot Length as a Predictor of Gestational Age

Fetal foot length as a predictor of gestational age

Ultrasonographic measurement of fetal foot length is useful in the assessment of gestational age. Two hundred twenty-three postpartum and 224 ultrasonographic measurements were performed between 11 and 43 weeks' gestation; 207 postpartum and 160 ultrasonographic measurements met our requirements of secure dates and no physical anomaly or maternal disease. Mean foot length at each week of gestation compared favorably with Streeter's data, based on pathologic specimens, described in 1920. Comparison of curvilinear regression of foot length versus gestational age demonstrated a strong correlation with an R2 value of 0.981; 95% confidence intervals at each week compared favorably with both biparietal diameter and femur length data. Fetal foot length is a reliable parameter for use in the assessment of gestational age and is particularly useful when other parameters do not accurately predict gestational age, for example, hydrocephalus, anencephaly, short limb dysplasia.

A prospective evaluation of fetal femur length as a predictor of gestational age.

Variability (+/- 2 SD) in prediction of fetal gestational age from ultrasonographic measurements of fetal femur length was evaluated prospectively in 287 fetuses between 18 and 42 weeks' gestation. Variability increased throughout pregnancy, ranging from +/- 11.6 days between 18 and 24 weeks to +/- 22.7 days in the last six weeks of pregnancy. These findings are comparable with variability in prediction of gestational age from biparietal diameter measurement between 18 and 42 weeks, which indicates that the femur length may serve as an adequate alternative for prediction of gestational age in cases in which the biparietal diameter cannot, for technical reasons, be obtained.

Fetal development in relation to gestational age in the piglet.

Body and organ weights were measured in piglets from 44 litters which had been delivered by caesarean section at various times during the last 20 days of gestation. An attempt has been made to assess the usefulness of these measurements as predictors of gestational age. In this series of animals there was a highly significant correlation between mean litter weight and age. However, a considerable degree of uncertainty about the true gestational age must be accepted if mean litter weight is to be used as the sole predictor: at a mean litter weight of 1 kg, the 95% confidence limits were found to be +/- 10.2 days. No extra information was afforded by the inclusion of the organ weight data one the mean litter weight was known.

Sonography and amniocentesis as predictors of gestational age and fetal growth in the rhesus monkey

Repetitive determinations of increasing fetal biparietal diameter were made in 8 pregnant rhesus monkeys with B-scan ultrasound. There was a plateau in skull growth after 120 days' gestation. Amniotic fluid aspirated at 115, 132, 148, and 155 mean days' gestation was analyzed for lecithin and sphingomyelin concentrations. Gestational ages were known to ± one day in all fetuses. Peak levels of lecithin appeared in amniotic fluid at 148 days of pregnancy, with a lecithin:sphingomyelin ratio of 2.3:1, partly because of decreased sphingomyelin. Fetal size does not appear to be an influence upon lecithin secretion into amniotic fluid in the rhesus monkey. Two animals with glucose intolerance induced by Streptozotocin∗∗The Upjohn Co., Kalamazoo, Michigan. showed decreased phospholipid values in amniotic fluid and a mean lecithin:sphingomyelin ratio of 1.2:1 at 142 days' gestation. Acetone-precipitated lecithin was found to be an increasing fraction of total lecithin during progression of pregnancy.