Current concepts of fetal growth restriction: part II. Diagnosis and management

Uterine artery Doppler longitudinal changes in pregnancies complicated with intrauterine growth restriction without preeclampsia

OBJECTIVE

The objective of this article is to evaluate the longitudinal changes in uterine artery Doppler pulsatility index (UtA-PI) in pregnancies complicated with early onset intrauterine growth restriction (IUGR).

METHOD

Case-control study comparing UtA-PI from 20 to 34 weeks gestation in pregnancies affected by IUGR at 20 to 28 weeks and confirmed at delivery (cases), matched with 1000 controls. Multivariable analyses were used to estimate the UtA-PI as a function of both gestational age and IUGR severity. Finally, bootstrapping technique was used to internally validate the models.

RESULTS

We retrospectively retrieved 53 cases and 1000 controls. Regression line having log10 UtA-PI as dependent variable was a function of both gestational age and IUGR. UtA-PI decreased with gestational age in both groups. In IUGR group, UtA-PI was higher from 20 weeks onward and the difference with controls increased with gestational age. In fact, at 20 weeks, the UtA-PI ratio between cases and controls was 1.84, but at 30 weeks it rose to 2.05. Finally, the weight at delivery in the IUGR group was also inversely correlated with the UtA-PI values.

CONCLUSION

We presented a reliable multivariable statistical model to evaluate the temporal changes of UtA-PI values as a function of both gestational age and IUGR.

Predicting fetal growth restriction with renal volume using 3-D ultrasound: efficacy evaluation

Early detection and management of fetal growth restriction (FGR) is very important in prenatal care and daily practice, because FGR fetuses may suffer increased risk of perinatal morbidity and mortality. Renal volume (RV) might be one of the important parameters of fetal growth. Yet, no prenatal assessment of fetal RV in FGR fetuses by 3-D ultrasound (US) has been reported. We undertook a prospective and cross-sectional study using quantitative 3-D US to assess the efficacy of fetal RV in predicting FGR. All fetuses were singletons and were followed-up to delivery to determine whether they had FGR complications. In total, 221 fetuses without FGR and 28 fetuses with FGR were included. Our results showed fetal RV assessed by 3-D US can differentiate fetuses with FGR from fetuses without FGR. The best predicting threshold for FGR is at the tenth percentile of fetal RV. Using the tenth percentile as the cutoff, the efficacy of fetal RV in predicting FGR was sensitivity 96.4%, specificity 95.9%, positive predictive value 75.0%, negative predictive value 99.5% and accuracy 96.0%, respectively. Fetal RV assessed by 3-D US can be applied to detect FGR prenatally. We believe fetal RV assessment using 3-D US is a useful test in detecting fetuses with FGR.

Auditory processing deficits in growth restricted fetuses affect later language development

An increased risk for language deficits in infants born growth restricted has been reported in follow-up studies for more than 20 years, suggesting a relation between fetal auditory system development and later language learning. Work with animal models indicate that there are at least two ways in which growth restriction could affect the development of auditory perception in human fetuses: a delay in myelination or conduction and an increase in sensorineural threshold. Systematic study of auditory function in growth restricted human fetuses has not been reported. However, results of studies employing low-risk fetuses delivering as healthy full-term infants demonstrate that, by late gestation, the fetus can hear, sound properties modulate behavior, and sensory information is available from both inside (e.g., maternal vascular) and outside (e.g., noise, voices, music) of the maternal body. These data provide substantive evidence that the auditory system is functioning and that environmental sounds are available for shaping neural networks and laying the foundation for language acquisition before birth. We hypothesize that fetal growth restriction affects auditory system development, resulting in atypical auditory information processing in growth restricted fetuses compared to healthy, appropriately-grown-for-gestational-age fetuses. Speech perception that lays the foundation for later language competence will differ in growth restricted compared to normally grown fetuses and be associated with later language abilities.

Predicting fetal growth restriction by humerus volume: A three-dimensional ultrasound study

Prenatal diagnosis of fetal growth restriction (FGR) is very important, as FGR may have increased risks with perinatal morbidity and mortality. Fetal humerus dysplasia is associated with a variety of congenital syndromes and FGR. For the assessment of the efficacy of fetal humerus volume in predicting FGR, we undertook a prospective cross-sectional study using quantitative three-dimensional (3D) ultrasound (US). In total, 42 fetuses with FGR and 258 fetuses without FGR were included for the humerus volume assessment in utero by 3D US. All the fetuses were singletons and were followed up to delivery to determine whether they were complicated with FGR or not. Our results revealed that fetal humerus volume assessed by 3D US can differentiate fetuses with FGR from fetuses without FGR well. The best predicting threshold for FGR is at the 10th percentile by humerus volume. Using the 10th percentile as the cutoff, the sensitivity of fetal humerus volume in predicting FGR was 97.6%, specificity 87.2%, positive predictive value 55.4%, negative predictive value 99.6% and accuracy 88.7%. In conclusion, fetal humerus volume assessed by quantitative 3D US can be used to predict FGR prenatally. We believe fetal humerus volume assessment by 3D US would be a useful test in detecting fetuses with FGR.

Predicting fetal growth restriction with liver volume by three-dimensional ultrasound: efficacy evaluation

It is well-documented that fetal growth restriction (FGR) may have increased risks of perinatal morbidity and mortality. Early detection of FGR is crucial in prenatal care and daily practice. We undertook a prospective and cross-sectional study using quantitative 3-D ultrasound (US) to assess the efficacy of fetal liver volume (LV) in predicting FGR. During the study period, 42 fetuses with FGR and 375 fetuses without FGR were included for the LV assessment in utero by 3-D US. All the fetuses were singletons and had follow-up to delivery to ensure whether they were complicated with FGR or not. Our results revealed that fetal LV assessed by 3-D US can differentiate well fetuses with FGR from those without FGR. The sensitivity of fetal LV in predicting FGR was 97.6%, with specificity 93.6%, predictive value of positive test 63%, predictive value of negative test 99.7% and accuracy 94%. In conclusion, fetal LV assessed by quantitative 3-D US can be used to predict fetuses with FGR antenatally. Our data support that fetal LV assessment by 3-D US would be a useful test in detecting fetuses with FGR.

Fetal upper arm volume in predicting intrauterine growth restriction: a three-dimensional ultrasound study

As fetuses with intrauterine growth restriction (IUGR) may have increased risks with perinatal morbidity and mortality, prenatal diagnosis of IUGR is a very important issue in perinatology. To assess the efficacy of fetal upper arm volume in predicting IUGR, we undertook a prospective, cross-sectional study using quantitative three-dimensional (3D) ultrasound (US). In total, 40 fetuses with IUGR and 442 fetuses without IUGR were included for the upper arm volume assessment in utero by 3D US. All the fetuses were singletons and were followed up to delivery to establish whether they were complicated with IUGR or not. Our results showed that fetal upper arm volume assessed by 3D US can differentiate fetuses with IUGR from fetuses without IUGR well. The best predicting threshold for IUGR is at the 10th percentile by upper arm volume. Using the 10th percentile as the cutoff, the sensitivity of fetal upper arm volume in predicting IUGR was 97.5%, with specificity 92.8%, predictive value of positive test 54.9%, predictive value of negative test 99.8% and accuracy 93.1%. Furthermore, upper arm volume is the best parameter for detecting IUGR among the common fetal biometric indices, such as biparietal diameter (BPD), occipitofrontal diameter (OFD), head circumference (HC), abdominal circumference (AC), femur length (FL) and estimated fetal weight (EFW). In conclusion, fetal upper arm volume assessed by quantitative 3D US can be used to predict fetuses with IUGR antenatally. We believe fetal upper arm volume assessment by 3D US would be a useful test in detecting fetuses with IUGR.

Maternal physiology and complications of multiple pregnancy

Approximately 1% to 3% of all pregnancies in the United States are multiple gestations. The vast majority (97-98%) are twin pregnancies. Multiple pregnancies constitute significant risk to both mother and fetuses. Antepartum complications-including preterm labor, preterm premature rupture of the membranes, intrauterine growth restriction, intrauterine fetal demise, gestational diabetes, and preeclampsia-develop in over 80% of multiple pregnancies as compared with approximately 25% of singleton gestations. This article reviews in detail the maternal physiologic adaptations required to support a multiple pregnancy and the maternal complications that develop when these systems fail or are overwhelmed.

The efficacy assessment of thigh volume in predicting intrauterine fetal growth restriction by three-dimensional ultrasound

Intrauterine growth restriction (IUGR) is an important issue in perinatology. To assess the efficacy of fetal thigh volume (ThVol) in predicting IUGR, we undertook a prospective cross-sectional study using quantitative 3-D ultrasound (US). During the study period, 30 fetuses with IUGR and 282 fetuses with non-IUGR were included for the ThVol assessment in utero by 3-D US. All the fetuses were singletons and had follow-up to the delivery to determine whether they were complicated with IUGR or not. Our results showed fetal ThVol assessed by 3-D US can differentiate fetuses with IUGR from fetuses with non-IUGR well. Using the 10th percentile as the screening threshold, the sensitivity of fetal ThVol in predicting IUGR was 86.6%, with specificity 91.1%, predictive value of positive test 51.0%, predictive value of negative test 98.5% and accuracy 90.7%. In conclusion, fetal ThVol assessed by quantitative 3-D US can be used to predict fetuses with IUGR antenatally. We believe fetal ThVol assessment by 3-D US would be a useful test in detecting fetuses with IUGR.

Placental insufficiency and its consequences

Placental insufficiency is a process leading to progressive deterioration in placental function and a decrease in transplacental transfer of oxygen and nutrients to the fetus. The resulting fetal hypoxemia is the major stimulus involved in the reduction in fetal growth as an attempt to reduce metabolic demands by the growing fetus. Fetal growth restriction (FGR) is the second cause of perinatal death after prematurity and can complicate up to 6% of all pregnancies. It is becoming apparent that its occurrence has major impacts on the fetus and placenta with consequences on the cardiovascular, metabolic and neurological development up to adulthood. We are just starting to unveil some of the basic mechanisms involved in this complex adaptation that may lead to reprogramming of fetal organs development mostly the heart, pancreas, lungs and brain. It is becoming clear that future research is needed to develop strategies to improve antenatal detection of FGR, in addition to reduce the risk of abnormal neurodevelopment during childhood, and onset of common diseases in adulthood following pregnancies complicated with placental insufficiency.