The clinical significance of Doppler umbilical artery velocimetry in the small for gestational age fetus

Fifty-four women who were delivered of small for gestational age infants were studied antenatally by serially continuous-wave Doppler velocimetry. Outcomes were compared in the normal and abnormal systolic/diastolic ratio groups. Seventy-eight percent had an abnormal systolic/diastolic ratio. The group with an elevated systolic/diastolic ratio had a significantly higher incidence of abnormal fetal heart rate, pregnancy-induced hypertension, oligohydramnios, cesarean section for fetal distress, and admission into the neonatal intensive care unit. One third of the newborns required intermittent positive pressure ventilation. Average birth weight and gestational age at delivery were significantly lower and there were six perinatal deaths in the group with an elevated systolic/diastolic ratio and none in the group with a normal systolic/diastolic ratio. These data suggest that the small for gestational age fetus with normal umbilical artery velocimetry is at significantly lower risk than are those with abnormal ratios. This implies that management of the small for gestational age fetus may now be aided by a functional classification based on the umbilical artery velocity waveform.     

Randomised controlled trial of cardiotocography versus umbilical artery Doppler in the management of small for gestational age fetuses

Objective To compare the impact on use of resources in the management of small for gestational age babies using Doppler ultrasound versus cardiotocography.
Design A randomised controlled trial.
Setting A large district general hospital delivering 5500 to 6000 infants each year, 30% to 35% of which are to women of Pakistani origin.
Population One hundred and fifty women delivered of small for gestational age infants.
Main outcome measures Primary outcome measures were length of hospital inpatient stay and induction of labour rates. Secondary outcome measures included caesarean section rates and length of stay on neonatal unit.
Results The use of Doppler reduced average hospital inpatient stay from 2.5 days to 1.1 days, compared with cardiotocography ( P = 0.036). There was no effect on induction of labour rates or caesarean section rates. There was no significant difference in length of stay on the neonatal unit ( P = 0.33). There was a reduction in monitoring frequency and fewer hospital antenatal clinic visits.
Conclusion The use of Doppler ultrasound to manage small for gestational age infants reduces the use of resources, compared with cardiotocography.     

Fetal middle cerebral and umbilical artery Doppler after 40 weeks gestational age

Abstract

Objective: To determine the value of fetal Doppler indices named middle cerebral artery (MCA)-PI, umbilical artery (UA)-PI and MCA-PI/UA-PI ratio, and amniotic fluid volume assessment in pregnancies 280–294?d and their correlation with the mode of delivery and perinatal outcome.

Study design: Prospective observational study conducted on 100 whose gestational age (GA) from 40 to 42 weeks. MCA and UA Doppler and MCA-PI/UA-PI ratio, amniotic fluid volume (AFV) were assessed. They were divided into two groups based on the presence or absence of adverse perinatal outcome.

Results: Women with adverse perinatal outcome showed lower MCA-PI (0.92 versus 1.29), MCA-PI:UA-PI ratio (1.04 versus 1.83), lower gestational age when assessed by ultrasound (37.82 versus 39.48 weeks), lower neonatal birth weight (2705 versus 3108?g), fetal biophysical profile (BPP) (4.55 versus 7.21) when compared to women with normal perinatal outcome. They also had higher cases with oligohydramnios (34 versus 5), and higher UA-PI (0.89 versus 0.72).

Conclusion: Women with adverse neonatal outcome had higher UA-PI and lower MCA-PI, MCA-PI:UA-PI ratio, GA (by US), AFV, BPP, estimated fetal weight, neonatal birth weight when compared to those with normal perinatal outcome. Women with adverse neonatal outcome had a higher rate of cesarean section mostly due to fetal distress and induced VD due to oligohydraminos compared to the normal outcome group.     

Investigation and management of the small for gestational age fetus

The desire to identify the small for gestational age fetus is due to its association with stillbirth and poorer neonatal outcomes. The difficulty lies in determining which of these babies are just constitutionally small and healthy and which are growth restricted fetuses that are at significant risk of poor outcomes. Fetal growth restriction is often mediated through placental disease and shares a similar aetiological pathway to preeclampsia. Placental malperfusion results in impaired nutrient and oxygen delivery to the fetus. Appropriate risk assessment in early pregnancy and monitoring with symphysis fundal height measurement or ultrasound scans is a crucial part of the screening pathway. There is no effective treatment for growth restriction, so management is based on close monitoring and early delivery. Fetal growth restriction has better defined monitoring and delivery timing guidelines whereas it is more unclear and variable for fetuses considered only to be small for gestational age.     

Respiratory outcome in preterm small for gestational age fetuses with or without abnormal umbilical artery Doppler and/or maternal hypertension

Objective.?To study respiratory outcome in preterm small for gestational age (SGA) fetuses with or without signs of intrauterine growth restriction due to placental insufficiency, and with or without maternal hypertension.

Methods.?This was a retrospective study of 187 neonates with birth weight <10^th percentile and gestational age <34 weeks. Results from umbilical artery Doppler velocimetry were used to identify the abnormal Doppler subgroup.

Results.?No significant difference in respiratory outcome between SGA fetuses with normal (SGA-N) or abnormal (SGA-A) umbilical artery Doppler examination was found. Within the SGA-A group, the respiratory distress syndrome (RDS) incidence (OR 5.6, 95% CI 1.7–18.3), RDS grade (OR 6.7, 95% CI 1.2–38.5), and need for surfactant (OR 5.3, 95% CI 1.1–24.4) were higher in infants of women with hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome as compared to those of normotensive mothers.

Conclusions.?Lung maturation is not accelerated with placental insufficiency. SGA-A fetuses of mothers with HELLP syndrome have a significantly poorer respiratory outcome than those with healthy mothers. Possibly, fetuses of mothers with HELLP syndrome are subjected to ‘oxidative stress’ causing lung damage rather than lung maturation.     

Predicting the risk of preeclampsia and small for gestational age infants by uterine artery Doppler in low-risk women

The objective was to assess the value of uterine artery notching as a screening test for preeclampsia and fetal growth restriction in a low-risk population of healthy pregnant women. Color Doppler ultrasound was used to examine both uterine arteries in 322 healthy pregnant women at 24.9 +/- 1.9 (range 22-28) weeks of gestation. The criterion for abnormal results was a unilateral or bilateral presence of an early diastolic notch. The major end points were preeclampsia and small for gestational age (SGA) infants. Of the 322 women, 19 (5.9%) developed preeclampsia and six of them (1.9%) delivered SGA infants. An early diastolic notch was detected in 58 women (18%). The risk of developing preeclampsia and SGA infants in an abnormal Doppler study group was found to be greater than in that of a normal group (P<0.05). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for detecting preeclampsia were 36.8, 83.2, 12.1, and 95.5%, respectively; whereas detecting SGA infants were 67, 82.9, 6.9, and 99.2%, respectively. Women with an early diastolic notch have considerably a higher risk of developing preeclampsia and SGA infants. On the other hand, women with normal uterine artery waveforms are unlikely to develop preeclampsia and SGA infants. The test may be useful to minimize unnecessary interventions.     

Prediction of small for gestational age by logistic regression in twins

BACKGROUND: Small for gestational age (SGA) is one of the major determinants of perinatal mortality and morbidity, and may relate in adult diseases. Early prediction of SGA could be helpful for health care providers and public health workers in guiding antenatal management and prevention. The reported methods of SGA prediction are not satisfactory because the diagnostic performance is poor and the interval between prediction and delivery is too short. AIMS: To establish a SGA prediction model for twin pregnancies based on variables obtainable in early gestation. METHODS: We used a large twin registry United States data (1995-1997). The study subjects were randomly divided into two groups: group 1 to establish the prediction model by logistic regression and group 2 to validate the prediction model. SGA was defined as birth weight for gestational age z scores less than 10th percentiles. Pair of twin was the unit of analysis. Two sets of multiple logistic regression analyses with different outcome measures - one or both twins SGAs and both twins SGAs - were used to establish the prediction model. RESULTS: The sensitivity, specificity, and positive predictive value were 52.3, 62.5, and 21.5%, respectively, at the cutoff value 0.16 in a SGA prediction model based on maternal race, education, marital status, parity, prenatal care visit initiation, cigarette smoking, and paternal race. CONCLUSIONS: A prediction model based on determinants that can be obtained at early gestation might be useful in the management of pregnancies with high risk of SGA in twins.     

Validity of umbilical artery Doppler waveform versus umbilical vein Doppler waveform in the prediction of neonatal outcome in intrauterine growth restriction cases

ObjectiveTo assess the neonatal outcome in relation to umbilical vein Doppler compared to umbilical artery Doppler in growth restricted fetuses.MethodsA total of 72 pregnant women with singleton pregnancy between 28 and 38 weeks of gestation with risk of developing intrauterine growth restriction (IUGR) were recruited to the study. All women were subjected to full assessment via detailed history, clinical examination, obstetric assessment, routine laboratory assessment and ultrasonography examination for fetal assessment. Doppler examination of umbilical artery (UA) and umbilical vein (UV) was performed. Absent or reversed UA end diastolic flow (EDF) and pulsatile flow in the umbilical vein were examined for their efficacy to predict critical outcomes (still birth, neonatal death, IUGR).ResultsA total of 13 deaths (18%) were reported; 13.9% were neonatal deaths and 4.2% were stillbirths. Fetuses were grouped according to Doppler parameters: those with normal Doppler finding (n = 35), those with resistance index (RI) (n = 20), those with Absent UA EDF (n = 10) and those with reversed UA EDF (n = 7). Pulsatile UV waveform was reported among 9.7% of patients all of them had reversed UA EDF. Patients with absent/reversed EDF have significant association with critical neonatal outcomes as lower birth weight, perinatal deaths, and lower Apgar score. UV Doppler was abnormal in patients with more severe deterioration (patients with reversed UA EDF) while it was normal in all patients with increased RI and absent UA EDF. All cases with Pulsatile UV Doppler have shown higher incidence of critical neonatal outcomes.ConclusionUV Doppler assessment can aid in detection and prediction of critical perinatal outcomes however, it required further evaluation and assessment.     

Prediction of smallness for gestational age by maternal serum human chorionic gonadotropin levels and by uterine artery Doppler study

OBJECTIVES: To compare the utility of maternal serum human chorionic gonadotropin (MShCG) levels with that of uterine artery Doppler study in predicting small for gestational age (SGA) birth and pregnancy-induced hypertension (PIH). METHODS: MShCG assay and uterine artery Doppler study were performed in 359 consecutive pregnant women with singleton pregnancies. MShCG levels > or =2.0 multiples of the median at 15-18 weeks' gestation were considered to be elevated. An abnormal uterine artery Doppler velocimetry at 21-24 weeks' gestation was defined as a mean pulsatility index above the 95th percentile or the presence of an early diastolic notch in either uterine artery. The predictive values of MShCG levels and uterine artery Doppler velocimetry were evaluated for the risk of SGA birth and PIH. RESULTS: Forty-one subjects gave birth to SGA infants, and 20 developed PIH. Patients with MShCG elevation or abnormal uterine artery Doppler velocimetry showed a significantly higher incidence of SGA infants than the controls. The sensitivity and specificity of MShCG elevation for SGA birth were 17.1 and 93.4%, respectively, compared with abnormal uterine artery Doppler velocimetry, which had 24.4 and 94.3%, respectively. There was no significant difference between these methods. Elevated levels of MShCG and abnormal uterine artery Doppler velocimetry were not associated with PIH. CONCLUSION: Elevated levels of second-trimester MShCG were as sensitive and specific in predicting SGA births as abnormal uterine artery Doppler velocimetry.     

Respiratory outcome in preterm small for gestational age fetuses with or without abnormal umbilical artery Doppler and/or maternal hypertension.

OBJECTIVE: To study respiratory outcome in preterm small for gestational age (SGA) fetuses with or without signs of intrauterine growth restriction due to placental insufficiency, and with or without maternal hypertension. METHODS: This was a retrospective study of 187 neonates with birth weight <10(th) percentile and gestational age <34 weeks. Results from umbilical artery Doppler velocimetry were used to identify the abnormal Doppler subgroup. RESULTS: No significant difference in respiratory outcome between SGA fetuses with normal (SGA-N) or abnormal (SGA-A) umbilical artery Doppler examination was found. Within the SGA-A group, the respiratory distress syndrome (RDS) incidence (OR 5.6, 95% CI 1.7-18.3), RDS grade (OR 6.7, 95% CI 1.2-38.5), and need for surfactant (OR 5.3, 95% CI 1.1-24.4) were higher in infants of women with hemolysis, elevated liver enzymes, low platelets (HELLP) syndrome as compared to those of normotensive mothers. CONCLUSIONS: Lung maturation is not accelerated with placental insufficiency. SGA-A fetuses of mothers with HELLP syndrome have a significantly poorer respiratory outcome than those with healthy mothers. Possibly, fetuses of mothers with HELLP syndrome are subjected to 'oxidative stress' causing lung damage rather than lung maturation.     

Doppler velocimetry in the fetus with a single umbilical artery.

OBJECTIVE: To study Doppler velocimetry in fetuses with a single umbilical artery (SUA) as compared to normal. STUDY DESIGN: Private and clinic patients were referred to a perinatal center: 45 with SUA and 124 randomly selected fetuses with a three-vessel cord were studied from 18 to 41 weeks' gestation. Color Doppler flow and energy were utilized to evaluate the umbilical arteries at the fetal abdominal wall as well as the course around the bladder. In addition to Doppler velocimetry, an anatomic survey, estimated fetal weight (EFW) and amniotic fluid index (AFI) were assessed at each examination. RESULTS: Doppler velocimetry in SUA demonstrated indices in the normal range but lower than in normal cords from 26 weeks until near term. Anatomic anomalies were found in 8.9% of SUA as compared to 4.8% for three-vessel cords. Intrauterine growth restriction (IUGR) was seen in four cases of SUA and none in the control group. EFW and AFI for both groups were virtually identical. CONCLUSION: SUA cords theoretically carry a normal blood volume, and the decreased resistance to flow and larger arterial diameter allow this to occur. Anomalies and IUGR are elevated in infants with SUA. Overall, EFW and AFI were the same in both groups of patients.     

Predicting small for gestational age in the first trimester of pregnancy using maternal ophthalmic artery Doppler indices

Objective: To assess the capacity of maternal ophthalmic Doppler indices for predicting small for gestational age (SGA) newborns in the first trimester of pregnancy.

Methods: We performed a prospective observational cohort study involving 499 singleton pregnancies during the first trimester scan (11–14 weeks). The following maternal ophthalmic Doppler indices were assessed: pulsatility index (PI), first diastolic peak velocity (PD1) and peak ratio (PR)?=?PD1/peak systolic velocity. We considered SGA all newborns with weight below 10th percentile. We used chi-square test (χ²) to compare the groups. We used area under receiver operating characteristics (ROC) curves with 95% confidence intervals (CI) and detection rate of 5% of false positive of each maternal ophthalmic Doppler index and the mean uterine artery PI for prediction SGA.

Results: 27 (5.4%) patients delivered SGA newborns, 12 (2.4%) patients developed preeclampsia (PE) and delivered SGA newborns, and 460 had uneventful pregnancies (controls). We observed significant difference of PI and PR between SGA (SGA and SGA+PE) and control groups, p?=?0.043 and p?=?0.014, respectively. To 5% of false positive, the detection rate of SGA (SGA and SGA+PE groups) using PI, PD1 and PR were 14.8, 3.7, 14.8, 16.7, 16.7 and 16.7%, respectively. Mean uterine PI was significantly higher in the SGA+PE group (p?=?0.003).

Conclusion: The isolated use of maternal ophthalmic Doppler indices or in combination with uterine artery Doppler, in the first trimester of pregnancy, was not efficient to predict SGA newborns.     

Population-based study on antenatal corticosteroid treatment in preterm small for gestational age and non-small for gestational age twin infants

Objectives: To assess the associations between antenatal corticosteroid use (ACU), mortality and severe morbidities in preterm, twin neonates and compare these between small for gestational age (SGA) and non-SGA twins.

Materials and methods: Population-based study using data collected by the Israel National Very Low Birth Weight infant database from 1995 to 2012, comprising twin infants of 24–31 weeks' gestation, without major malformations. Univariate and multivariable logistic regression analyses were performed.

Results: Among the 6195 study twin infants, 784 were SGA. Among SGA neonates, ACU were associated with decreased mortality (23.9% vs. 39.2%, p?p?=?0.0015), similar to the effect in non-SGA neonates (mortality 13.0% vs. 24.5%, p?p?P_interaction?=?0.69. Composite adverse outcome risk was also reduced in SGA (OR?=?0.78, 95% CI 0.50–1.23) and non-SGA groups (OR?=?0.78, 95% CI 0.65–0.95), P_interaction?=?0.95.

Conclusions: ACU should be considered in all mothers with twin gestation, at risk for preterm delivery at 24–31 weeks, in order to improve perinatal outcome.     

Doppler umbilical artery waveform indices--normal values from fourteen to forty-two weeks

Normal values for Doppler waveform indices of the umbilical artery have been reported for gestational ages of 20 to 40 weeks in small numbers of normal patients. We evaluated 590 patients studies performed at 2-week intervals from 14 to 42 weeks' gestation on patients without medical or pregnancy complications. Readings were obtained during fetal quiet times (no fetal breathing or movements). Values for A (systolic) and B (diastolic) pressures were plotted as Pourcelot (A - B/A) and A/B ratios. Mean, SD, and 95% confidence limits were derived, and the skewness, kurtosis, and regression correlations were calculated. No diastolic flow was found in any pregnancy greater than 15 weeks' gestation (n = 25) or in 50% of the gestations between 15 to 17 weeks (n = 25). When diastolic pressure equals zero, the Pourcelot ratio value equals one and the A/B ratio approaches infinity and loses meaning. Recent work by Thompson et al. suggests that the Pourcelot ratio fits a normal distribution from 20 to 40 weeks' gestation and that the A/B ratio (which does not fit a normal curve) may be transformed to a normal distribution by conversion of the A/B ratio to 1/1 - Pourcelot ratio. Our data supports the normality of both indices from 18 to 42 weeks' gestation, but these assumptions are not applicable as the Pourcelot ratio approaches one or as the A/B ratio approaches infinity. Knowledge of normal umbilical flow ratios at gestational ages from 18 weeks may allow early detection and directed management of high-risk pregnancies.     

Identification of the small for gestational age fetus with the use of gestational age-independent indices of fetal growth

This study reviews the roles of sonographic assessment of the rate of growth of the fetal abdominal circumference, the femur length/abdominal circumference ratio, and qualitative determination of amniotic fluid volume as gestational age-independent indices for identification of the small for gestational age fetus. The sensitivity and specificity for single and combinations of test results were evaluated in 50 appropriate for gestational age and 40 small for gestational age fetuses. Positive and negative predictive values were derived for the general population. Our results indicate that either a rate of growth of the fetal abdominal circumference less than or equal to 10 mm/14 days or a femur length/abdominal circumference ratio greater than or equal to 23.5 correctly identifies most small for gestational age fetuses. When the general population is screened, only 15% of small for gestational age fetuses will be missed by this combination of criteria. The presence of a pocket of amniotic fluid less than or equal to 2.0 cm is highly suggestive of a small for gestational age fetus. However, the presence of a pocket of amniotic fluid greater than 2.0 cm does not guarantee an appropriate for gestational age fetus. We conclude that these gestational age-independent indices of fetal growth offer useful tools for differentiating between the small for gestational age and appropriate for gestational age fetus.     

Notching of the umbilical artery waveform associated with cord entanglement in a monoamniotic twin pregnancy

Abstract

Cord accidents are the principal cause of the high rates of morbidity and mortality associated with monoamniotic twins. Observation of an umbilical artery notch might be a highly specific sign for cord entanglement involving a tight cord knot. It thus justifies the implementation of intense surveillance and should be one of the factors taken into account in deciding on early delivery of the twins.     

Optimal gestational age for twin delivery.

OBJECTIVE: We evaluated the timing of twin delivery associated with perinatal outcome in gestations of at least 36 completed weeks. STUDY DESIGN: This was a retrospective analysis of infant and maternal hospital records for a consecutive series of twin deliveries at New York Hospital-Cornell Medical Center. The inclusion criteria were delivery after 36 weeks' gestation during a 7-year period (1987 to 1993), without congenital anomalies or early fetal demise. Adverse perinatal outcomes were compared between deliveries before 38 weeks' gestational age and those at or after 38 weeks' gestation. RESULTS: Of 776 twin deliveries during the study period, 329 met the inclusion criteria. Adverse perinatal outcome was significantly higher among the twin pregnancies that delivered before 38 weeks' gestation compared with those that delivered at or after 38 weeks' gestation. Twin pregnancies that delivered between 36 and 37 weeks' gestation were 13 times more likely to require neonatal intensive care compared with those who delivered at or after 38 weeks' gestation (95% confidence interval 1.8 to 95.9; p < 0.001). CONCLUSION: In uncomplicated twin gestations, delivery at between 36 and 37 weeks' gestation was not associated with a reduction in neonatal complications compared with deliveries at or after 38 weeks' gestation.