|Year : 2021 | Volume
| Issue : 2 | Page : 88-93
Neonatal outcome of babies born to mothers with abnormal umbilical artery doppler
JP Padma, Lathika Nayar
Department of Paediatrics, Government Medical College, Trissur, Kerala, India
|Date of Submission||22-Jan-2021|
|Date of Decision||12-Feb-2021|
|Date of Acceptance||22-Feb-2021|
|Date of Web Publication||15-Apr-2021|
Dr. J P Padma
Department of Paediatrics, Government Medical College, Trissur, Kerala
Source of Support: None, Conflict of Interest: None
Background: Umbilical artery Doppler reflects the status of placental circulation. Very few studies have reported the outcome of intrauterine growth restriction infants with abnormal Doppler flow pattern. Methodology: This prospective observational study was conducted between February 2014 and December 2014. Antenatal mothers with umbilical artery Doppler abnormality, admitted our labor room were recruited and neonates were followed up till postnatal day 28 or till the date of hospital discharge whichever is later. Results: During the study, 201 antenatal mothers with abnormal umbilical artery Doppler admitted to labor room were included in the study. More than half, 107 (53%) babies were preterm. Of the 184 live babies, 57 (28%) had respiratory distress of which 36 had transient tachypnea of the newborn, 12 had hyaline membrane disease and 8 had meconium aspiration syndrome. Absent or reversal of end-diastolic flow was more in those mothers with preeclampsia. The rate of intensive care unit admissions was significantly higher in absent or reversal of diastolic flow (AREDF) group when compared to forward end diastolic flow (FEDF) group. Preterm small for gestational age babies and perinatal asphyxia were significantly high in pregnancy-induced hypertension (PIH) group. Conclusions: Neonates with absent or reversal of diastolic flow in umbilical artery have significantly higher morbidity and mortality when compared to those with FEDF. Even within the abnormal Doppler group, PIH adversely affects the perinatal and neonatal outcome, indicating that PIH is an independent risk factor in predicting adverse perinatal and neonatal outcome.
Keywords: Abnormal umbilical artery, Doppler, neonatal outcome, neonates
|How to cite this article:|
Padma J P, Nayar L. Neonatal outcome of babies born to mothers with abnormal umbilical artery doppler. Curr Med Issues 2021;19:88-93
| Introduction|| |
Low birth weight (LBW) is a common problem in India. Nearly 3 million LBW babies are born annually in India. The incidence of LBW in India varies from 15% to 25%, of which more than 50% are due to intrauterine growth restriction (IUGR). This can be caused by a number of conditions but pregnancy-induced hypertension (PIH) and vascular disorders of the placenta are the most common etiologies associated with 25%–50% of IUGR., Although the incidence of IUGR in western world is 8%, the prevalence in developing world is much higher at 35%.
Although different modalities are used for fetal surveillance of IUGR, umbilical Doppler pattern is one of the most widely used tests. Although multiple maternal conditions cause IUGR, placental vascular insufficiency (75%–80%) is the major factor, which is reflected as abnormal diastolic flow. Absent or reversed diastolic flow is associated with fetal hypoxia and acidosis which need immediate termination of pregnancy, thus increasing cesarean sections and also prematurity-related complications. Perinatal asphyxia is the most important complication associated with IUGR due to placental insufficiency.
Umbilical artery Doppler reflects the status of placental circulation. Umbilical arterial circulation is normally a low impedance circulation with an increase in diastolic flow with advancing gestation, which is a direct result of increase in the number of tertiary stem villi. This is reflected as low systolic/diastolic (S/D) ratio with advancing gestation. Diseases that obliterate small muscular arteries in placental tertiary stem villi result in progressive decrease in end diastolic flow. This is reflected as high S/D ratio. Absent or reversed diastolic flow in umbilical artery circulation represents an advanced stage of placental compromise and is associated with more than 70% of placental arterial obliteration. An increase in S/D ratio even if it is marked is not an indication of fetal hypoxemia or acidosis. Absent or reversed diastolic flow is commonly associated with severe intrauterine growth retardation, oligohydramnios, and fetal hypoxemia which needs immediate delivery of fetus.
A number of observational studies have reported the outcome of IUGR infants with abnormal Doppler flow pattern. However, there are only few studies in developing countries regarding the same. This study is designed to find the immediate neonatal outcome (till postnatal day 28 or till the time of discharge from hospital, whichever is later) of babies born to mothers with abnormal antenatal umbilical artery Doppler and an internal comparison of the neonatal outcome between the PIH group and the non-PIH group.
| Methodology|| |
This was a prospective cohort study.
The study was conducted in the Department of Pediatrics and Department of Obstetrics and Gynecology, Government Medical College, Trissur, Kerala.
February 2014 to December 2014.
Aims and objectives
- To study the neonatal outcome of babies born to mothers with abnormal umbilical artery Doppler
- To make comparison between the outcome of babies born to mothers with PIH and without hypertension within the study group.
Antenatal mothers with umbilical artery Doppler abnormality admitted our labor room. Neonates of these mothers were studied till postnatal day 28 or till the date of hospital discharge whichever is later.
Definition of abnormal umbilical artery
Doppler: Abnormal umbilical artery Doppler is defined by the presence of any of the three features given below:
- Reduced diastolic flow
- Absent diastolic flow
- Reversal of diastolic flow.
Antenatal mothers with abnormal umbilical artery Doppler, admitted in the labor room of Government Medical College, Thrissur, during the study.
Mothers who did not give consent for the study.
All antenatal mothers with suspected IUGR during routine antenatal checkup or high-risk pregnancies were subjected for Doppler study which was done in the department of radiology.
Imaging was done by image point color Doppler machine with convex probe 3.5 MHz. Patient in recumbent position, fetal biometry, and morphology scan was done, and then Doppler mode was switched on. The transducer is placed over the anterior abdominal wall, carefully manipulated till a free loop of umbilical cord seen by gray scale imaging and color was used to identify the umbilical artery. The Doppler waveforms were identified with the characteristic audio output and typical Doppler shift waveforms appearance on the screen, parameters studied are S/D ratio and resistance index and pulsatility index in fetal umbilical artery.
Those mothers admitted to labor room, detected to have abnormal umbilical artery Doppler during the study period were selected and informed written consent was taken. A pro forma regarding maternal details was obtained. Gestational age was calculated based on first trimester ultrasound scan and mothers last menstrual period.
Outcomes were followed up in terms of perinatal mortality, birth weight, incidence of perinatal asphyxia, need for neonatal intensive care unit (NICU) admission, prematurity, respiratory distress syndrome, need for ventilator support, duration of ventilator support, metabolic abnormalities such as hypoglycemia, necrotizing enterocolitis (NEC), incidence of sepsis, feed intolerance, and duration of hospital stay. Babies were followed up for 28 days.
Outcomes were evaluated in three sessions
- The overall maternal characteristics, maternal risk factors, perinatal mortality, and neonatal outcomes were analyzed in the study group. Still births were excluded while analyzing the neonatal outcome
- The study group was divided into two groups, those with reduced diastolic flow named as forward end diastolic flow (FEDF) group, and those with absent or reversal of diastolic flow (AREDF) group, and the maternal and neonatal characteristics were compared
- The study group was again divided into those with PIH and those without PIH and the neonatal outcomes were compared.
Still births and babies with major malformations were excluded while comparing the neonatal outcome.
All antenatal mothers with abnormal umbilical artery Doppler, admitted to labor room during the study period were followed up and immediate neonatal outcome of their babies were studied. Based on a previous study, the sample size was calculated with formula 4pq/d2 and found to be 295.
Data analysis was done using Statistical package for Social Sciences (SPSS) for Windows (SPSS Inc. Released 2014, version 23.0, Armonk, NY, USA). Quantitative data analyzed using mean and standard deviation (SD). The association of abnormal umbilical artery Doppler and PIH with the perinatal outcome was assessed using Chi-square test. Difference between means was analyzed using independent t-test. The significance level was kept at 5% level.
This study was done after approval from the institutional review board and ethics committee dated January 27, 2014. We used unique identifiers and password protected data entry software to maintain patient confidentiality.
| Results|| |
During the study, 201 antenatal mothers with abnormal umbilical artery Doppler admitted in labor room were included in the study after obtaining an informed written consent. The maternal characteristics and neonatal outcome were analyzed. Mean maternal age in this group was 25.56 years with SD of 5.29. Baseline characteristics are shown in [Table 1]. In the study cohort, 22.4% had a history of previous abortions. Fourteen mothers had gestational diabetes mellitus and 15 had overt diabetes. One hundred and sixty-seven mothers had decreased diastolic flow in umbilical artery, 20 had absent flow and 14 had reversal of flow in the umbilical artery [Table 2]. Of the 201 deliveries, 77 (38%) were born by emergency lower section cesarean section. Mean gestational age in study group at the time of delivery was 35.39 with SD of 2.6. The gestational age at delivery and birth weight is shown in [Table 3].
More than half, 107 (53%) babies were preterm. Out of 201 babies, 27 had perinatal asphyxia of which 17 were LBW still birth. Half (53%) of abnormal Doppler group needed admission in NICU. Of the 184 live babies, 57 (28%) had respiratory distress of which 36 had transient tachypnea of the newborn, 12 had hyaline membrane disease (HMD) and 8 had meconium aspiration syndrome. All the babies with HMD were given surfactant. Of the 184 live babies, 11 had apnea of prematurity and 18 required ventilator support.
Of the 184 live babies, 51 had feed intolerance, 18 had symptomatic hypoglycemia, and 16 had asymptomatic hypoglycemia. We could not start feed in 4 cases because these babies expired before introduction of feed. The mean duration taken to tolerate feed is 2.48 days with SD of 3.33. Of the 21 in whom feed was not started, 17 were still birth and 5 died during the treatment. Of the 184 live babies 56 had necrotizing enterocolitis, mostly class 1b, while 35 had culture proven sepsis. Of the 184 live babies, 5 had symptomatic polycythemia requiring partial exchange. 9.8% of live babies required hospital stay of >28 days.
The 201 pregnant mothers with abnormal umbilical artery Doppler were divided into two groups, one with reduced FEDF group (n = 167) and other with AREDF group (n = 34). Comparison of neonatal outcome between FEDF and AREDF groups is shown [Table 4]. Absent or reversal of end diastolic flow was more in those mothers with preeclampsia and this difference was statistically significant. Oligoamnios was significantly higher in AREDF group when compared to FEDF group. Five babies in AREDF group did not have oligoamnios. Prematurity and perinatal asphyxia were significantly high in AREDF group when compared to FEDF group. There were 44.1% still births and 17.6% neonatal deaths in AREDF group. The rate of intensive care unit (ICU) admission was significantly higher in AREDF group when compared to FEDF group. Seventeen still birth cases and 4 dysmorphic babies were excluded while comparing the neonatal outcome. Outcome variables between FEDF group (n = 167) and AREDF group (n = 34) are shown in [Table 5].
|Table 4: Comparison of maternal characteristics, antenatal risk factors and the neonatal outcome between forward end diastolic flow group (n=167) and absent or reversal of diastolic flow group (n=34)|
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|Table 5: Outcome variables between forward end diastolic flow group (n=167) and absent or reversal of diastolic flow group (n=34)|
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The study group was divided into those with PIH (n = 86) and those without PIH (n = 115). Comparison of neonatal outcomes between these two groups is shown in [Table 6]. Still birth (n = 17) and babies with major dysmorphism were excluded while comparing the neonatal outcome between two groups. Preterm small for gestational age (SGA) babies and perinatal asphyxia were significantly high in PIH group.
|Table 6: Comparison of neonatal outcome between those with pregnancy induced hypertension (pregnancy induced hypertension: n=86) and those without pregnancy induced hypertension (n=115)|
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| Discussion|| |
Umbilical artery Doppler is a noninvasive technique that evaluates abnormal fetal hemodynamics which results in abnormal pregnancy outcome. It has been shown by various workers that perinatal morbidity and mortality were significantly greater in SGA babies with abnormal umbilical artery Doppler studies than in those with normal Doppler studies.
In our study, the mean maternal age was 25.56 years. In a previous study, the mean maternal age was 27 in abnormal Doppler group and 26.7 in normal Doppler group. Mothers of SGA babies with abnormal Doppler studies were more likely to have a history of obstetric complications in the previous pregnancy as observed by McCowan et al. They had high incidence of delivering SGA babies, and history of perinatal death in the previous pregnancy. According to Arora et al., there was a trend for more underlying medical problems such as PIH and diabetes mellitus in mothers with abnormal Doppler studies.
In abnormal Doppler study group, 82 (40.8%) fetuses did not have oligoamnios and 22 (10.9%) did not have IUGR. Twenty-five (12%) babies had normal birth weight which is contrary to what we expect. However, study by Arora et al. support these data. Those who did not have oligoamnios or IUGR have only minimal abnormality in diastolic flow. Umbilical artery Doppler flow studies have limited value after 36 weeks' gestation. Our study group included mothers detected to have abnormal Doppler after 36 weeks of gestation this may be the possible explanation of babies with normal birth weight in the study group. Of the total of 201 babies 133 (66%) were preterm. In a study by Arora et al., the incidence of prematurity in normal Doppler group was 17% and that of abnormal Doppler group was 56%.
McCowan et al. found that the effect of abnormal umbilical artery Doppler was not important in terms of NICU admission. Whereas a recent work of Vergani et al. showed that abnormal umbilical Doppler velocimetry is an independent predictor of the likelihood of admission to NICU. The mean NICU stay was 7.89 days for the study group. When the neonatal outcome was compared between FEDF and AREDF groups, AREDF group is found to have significantly increased morbidity and mortality when compared to FEDF group, which is comparable with the previous studies., The incidence of prematurity, SGA, and LBW were significantly higher in AREDF group when compared to FEDF group which is comparable with previous studies., The high incidence of prematurity may be due to early termination of pregnancy. In a study by Arora et al., there were 85% premature babies in AREDF group when compared to 43% in FEDF group.
All neonates with AREDF group needed NICU admission but only 50% of FEDF needed NICU admission. Hence, AREDF directly correlates with NICU admission. In a study by Arora et al. the rate of ICU admission was 100% in AREDF group and 70% in FEDF group. Perinatal asphyxia was significantly higher in AREDF group. There were 44% still birth and 17.6% neonatal death in AREDF group. Since our institution is a tertiary care center most of the mothers are referred here after detecting the abnormality in Doppler.
Ideally, those with reversal of diastolic flow should be immediately terminated. Hence, the delay in termination of pregnancy may be the reason for increased still birth in AREDF group. Only 3 (23%) babies with reversal of diastolic flow survived. There was significantly higher mortality in AREDF group comparing to FEDF group similar to the previous study.,
Prematurity-related complications such as HMD, apnea of prematurity, feed intolerance, and NEC were higher in AREDF group and it was statistically significant which is comparable with previous studies.,,, The incidence of hypoglycemia was significantly higher in the present study when compared to previous studies, it may be due to prompt detection or due to inadequate fluid management. According to McCowan et al., hypoglycemia in neonates was found to be dependent on the birth weight and not on abnormal umbilical artery Doppler findings. The incidence of culture proven sepsis was low in our study when compared to other studies, probably due to reduced yield or due to early introduction of antibiotic in suspected case of sepsis.
Umbilical artery velocimetry correlates with the hemodynamic changes in fetoplacental circulation and hence with the severity of PIH. There is significantly higher incidence of prematurity and SGA in the PIH group when compared to non-PIH abnormal Doppler group. Sharma et al. in their study concluded that infants of hypertensive mothers had a higher incidence of LBW, very LBW, low Apgar score at 5 min, NEC and polycythemia. Kim et al. concluded that perinatal complications are more directly influenced by gestational age at delivery and birth weight than severity of hypertensive disease. According to Sivakumar et al., there was higher number of preterm, IUGR and SMA babies among the infants of hypertensive mothers.
| Conclusions|| |
Neonates with absent or reversal of diastolic flow in umbilical artery have significantly higher morbidity and mortality when compared to those with FEDF. Even within the abnormal Doppler group PIH adversely affects the perinatal and neonatal outcome, indicating that PIH is an independent risk factor in predicting adverse perinatal and neonatal outcome.
Research quality and ethics statement
The authors of this manuscript declare that this scientific work complies with reporting quality, formatting and reproducibility guidelines set forth by the EQUATOR Network. The authors also attest that this clinical investigation was determined to require Institutional Review Board/Ethics Committee review, and the corresponding approval was B6-15226/2014/MCTCR dated January 27, 2014. We also certify that we have not plagiarized the contents in this submission and have done a plagiarism check.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6]