Maternal fetal medicine: recent developments and moving forward
CURRENT OPINION IN OBSTETRICS & GYNECOLOGY
Lyell, D. J., Boddy, M., Rode, M.
2018; 30 (2): 100?101
Postpartum x-ray pelvimetry - Its use in calculating the fetal-pelvic index and predicting fetal-pelvic disproportion
JOURNAL OF REPRODUCTIVE MEDICINE
O'Brien, K., Rode, M., Macones, G.
2002; 47 (10): 845?48
Abstract
To determine whether postpartum x-ray pelvimetry can be used to calculate the fetal-pelvic index (FPI) in future pregnancies.In stage I of the study, 10 gravid women, after 36 completed weeks' gestation, underwent x-ray pelvimetry before delivery. Pelvimetry was repeated within two days after delivery. Comparisons between antepartum and postpartum measurements were made using paired t tests and correlation coefficients. In stage II, 25 gravid women, after 36 completed weeks' gestation, underwent fetal ultrasound for biometry. X-ray pelvimetry was performed within two days after delivery. FPI was calculated for each pregnancy using antepartum fetal ultrasound and postpartum pelvimetry measurements. FPI calculations were correlated with the incidence of fetal-pelvic disproportion (FPD), as indicated by the requirement for cesarean section for arrest of active labor. Sensitivity, specificity and predictive value of FPI were assessed.In stage I, mean anteroposterior and transverse diameters of the pelvic inlet, midpelvis and pelvic outlet did not differ significantly. In stage II, the sensitivity of FPI for detecting FPD was 100%, specificity 95%, positive predictive value 80%, and negative predictive value 100%.Postpartum pelvimetry has the same association with FPD as antepartum pelvimetry. The strategy of using postpartum pelvimetry and antepartum fetal biometry to calculate FPI successfully identified 100% of the patients who ultimately required cesarean section for FPD, with a false positive rate of 5%. Pelvimetry performed postpartum in an index pregnancy may be used in future pregnancies, in combination with antepartum fetal ultrasound, to calculate FPI and predict the likelihood of FPD.
View details for Web of Science ID 000178826800009
View details for PubMedID 12418069
Abstract
To determine whether ultrasonographic measurements of the abdominal circumference are smaller in fetuses with congenital diaphragmatic hernia and whether this is reflected as an underestimation of the estimated fetal weight.A retrospective review of 225 abdominal circumference measurements made between 24 and 41 weeks of gestation in 85 fetuses with congenital diaphragmatic hernia was performed. The individual and mean abdominal circumference value at each week of gestation versus gestational age was plotted and compared with normative data. Comparisons between abdominal circumference measurements and hernia variables were made with the chi(2) test. The Pearson correlation was used to examine the accuracy of ultrasonographic determination of the estimated fetal weight.The mean measurements of abdominal circumference were not found to differ significantly from normative data until term, although fetuses with liver herniation were less likely to have measurements more than 2 standard deviations below the mean. Calculation of estimated fetal weight was similar in accuracy to that in normal fetuses.Small abdominal circumference measurements should not be expected in fetuses with congenital diaphragmatic hernia. Abnormalities of the abdominal circumference or an abdominal circumference-dependent estimated fetal weight should not be attributed to the anatomic defect without considering other etiologies.
View details for PubMedID 11854658
Abstract
OBJECTIVE: We report the feasibility of measuring photon migration through the fetal head in utero using antepartum, transabdominal, near infrared (NIR) spectroscopy.METHODS: We developed a continuous wave (CW) spectrometer that incorporates a halogen light source, silicon photodetectors, and a differential processing circuit for antepartum, transabdominal, NIR spectroscopy. By placement of the light source and photodetector on the midline of the maternal abdomen above the fetal head at a separation (approximately 10 cm) large enough for the light to propagate through maternal and fetal tissues via multiple scattering events before being detected at the surface and the use of filtered illumination and detection at wavelengths (760 nm, 850 nm), which coincide with the absorption bands of oxygenated and deoxygenated hemoglobin in the NIR window, we performed studies to evaluate whether antepartum, transabdominal NIR spectroscopy can measure photon migration through the fetal head in utero.RESULTS: The results demonstrate that the CW spectrometer we developed can be employed to make NIR measurements from the maternal abdomen at a 10 cm source-detector separation, with an excellent signal-to-noise ratio. Furthermore, a variety of antepartum, transabdominal NIR measurements that we performed on patients undergoing a routine nonstress test demonstrate the feasibility of measuring photon migration through the fetal head in utero.CONCLUSIONS: Preliminary assessment of transabdominal NIR spectroscopy suggests that this technique can enable photon migration through the fetal head in utero. This is an important step towards the development of this technique for measuring and quantifying fetal cerebral blood oxygenation in utero.
View details for PubMedID 10582862
Abstract
Determination of chorionicity is of paramount importance in risk assessment and management. Best performed in the first trimester, dichorionic placentation can be reliably assumed when the membrane is easily seen, there is a "twin peak" sign, there are clearly separate placentas, and there is discordant fetal gender. In a monochorionic twin pregnancy, there is a single placental mass, the dividing membrane is difficult to visualize until the end of the first trimester, and the membrane inserts onto the placental surface without a peaked appearance. Amniotic fluid volume assessment is important in the management of twin pregnancy. Polyhydramnios-oligohydramnios may be a manifestation of twin-twin transfusion syndrome, although oligohydramnios with normal amniotic fluid volume in the other twin's sac may more likely be a sign of velamentous cord insertion, infection, or chromosomal or structural abnormality. Fetal growth discordance is common in twin pregnancy and is associated with increased perinatal mortality and morbidity. The most sensitive indicator of discordant twin growth is thought to be estimated fetal weight, and an intertwin difference of > or = 20% is considered significant. In the clinical care of a patient with twins, it is reasonably standard to confirm chorionicity with ultrasonography in the first or early second trimester. At about 20 weeks, a level II ultrasound for anatomic survey is indicated. In dichorionic pregnancies, ultrasound examinations are then performed at 26 to 28 weeks and every 3 to 4 weeks thereafter to follow growth and amniotic fluid volume. In monochorionic twins, we generally do an additional ultrasound at about 23 to 24 weeks, because of the risk of twin-twin transfusion syndrome. In the late third trimester, careful attention should also be given to fetal position, to help with delivery planning.
View details for DOI 10.1016/S0037-198X(99)80017-0
View details for Web of Science ID 000078122500005
View details for PubMedID 9988860
