Superior mesenteric artery blood flow velocity in small for gestational age infants of very low birth weight during the early neonatal period

In order to elucidate intestinal blood flow after birth in infants with intrauterine growth retardation, we measured superior mesenteric artery blood flow velocity in uncomplicated small for gestational age infants with a birth weight of < 1500 g by pulsed Doppler ultrasound in days 1 to 7 of life. Peak systolic blood flow velocity, time-averaged mean blood flow velocity and end-diastolic blood flow velocity in the superior mesenteric artery significantly increased with time. The resistance index and relative vascular resistance in the superior mesenteric artery significantly decreased after birth. Compared with gestational age matched appropriate for gestational age infants and birth weight matched appropriate for gestational age ones, peak systolic blood flow velocity, time-averaged mean blood flow velocity and end-diastolic blood flow velocity in the superior mesenteric artery were lower in the small for gestational age infants. The difference between the small for gestational age group and the gestational age matched appropriate for gestational age group was statistically significant. The resistance index and relative vascular resistance in the superior mesenteric artery tend to be higher in the small for gestational age group than in the appropriate for gestational age groups. In conclusion, although intestinal blood flow velocity in infants with intrauterine growth retardation increases after birth, it is lower than appropriate for gestational age infants during the early neonatal period.     

Maternal hypertension and neonatal outcome among small for gestational age infants

OBJECTIVE: To determine whether maternal hypertension might improve perinatal outcome among small for gestational age (SGA) infants (< 10th percentile). METHODS: Our prospective cohort comprised 17 Canadian neonatal intensive care units (NICUs) and 3,244 SGA singletons. Multivariable regression was used to analyze the relation between maternal hypertension and each of the following: SNAP-II (Score of Neonatal Acute Physiology; ordinal regression) and neonatal survival and survival without severe intraventricular hemorrhage (logistic regression), adjusting for potential confounders. RESULTS: There were 698 (21.5%) neonates born to hypertensive mothers. Inversely associated with lower SNAP-II scores (healthier infant) were antenatal steroids (complete course: odds ratio [OR] 0.67, 95% confidence interval [CI] 0.54-0.83; incomplete: OR 0.71, 95% CI 0.56-0.88), lower gestational age (< 27 weeks: OR 0.06, 95% CI 0.05-0.08; 27-28 weeks: OR 0.11, 95% CI 0.07-0.17; 29-32 weeks: OR 0.28, 95% CI 0.23-0.35), 5-minute Apgar < 7 (OR 0.30, 95% CI 0.25-0.36), male gender (OR 0.80, 95% CI 0.70-0.92), and anomalies (OR 0.49, 95% CI 0.41-0.58). Maternal hypertension was associated with lower SNAP-II (healthier infant) (7.54 +/- 11.16 [hypertensive] versus 7.21 +/- 11.85 [normotensive]) on multivariable regression analysis (adjusted OR 1.25, 95% CI 1.05-1.49), as well as higher neonatal survival (93.0% versus 91.2%, and adjusted OR 1.9, 95% CI 1.2-3.0), but not survival without severe intraventricular hemorrhage (91.4% versus 87.0%, and adjusted OR 1.4, 95% CI 1.0-2.0), respectively. CONCLUSION: Among SGA neonates in NICU, maternal hypertension is associated with improved admission neonatal physiology and survival.     

Effect of small for gestational age on hemodynamic parameters in the neonatal period

Objective: The time course over which hypertension develops in children with a history of growth restriction has not been fully elucidated. The purpose of this study was to determine whether commonly obtained hemodynamic parameters were different between small for gestational age (SGA) and appropriate for gestational age (AGA) neonates. Methods: This was a retrospective case–control study matching 24 SGA neonates in a 1:2 fashion with 48 AGA neonates delivered during the same gestational week. Hemodynamic parameters were evaluated during the first week of life and the week prior to discharge. Results: There were no differences in blood pressure (BP) parameters during the first week of life. Compared to AGA controls, SGA neonates had a significantly lower heart rate (HR) at birth (148.2 ± 19.2 vs. 159.2 ± 17.1, p < 0.001), and a greater need for vasopressor support (OR 5.66; 95% CI 2.28, 14.04). The SGA neonates had a lower systolic BP during the week prior to discharge (68.3 ± 1.2 vs. 73.5 ± 1.2 mmHg, p < 0.001). Conclusions: SGA newborns had a lower HR at birth and greater need for vasopressor support during the first week of life despite similar BP parameters. SGA newborns had a lower systolic BP prior to discharge. Further studies are needed to understand the progression to adult hypertension.     

高危新生儿期危险因素及与出生胎龄的相关性研究

目的通过分析高危新生儿期危险因素的发生率及与出生胎龄的相关性,探讨其可能的发病机制。方法 2012年6月至2013年6月大连市儿童医院收治住院的高危新生儿1 800例,随机抽取1 000例高危儿中发生在新生儿期的高危儿780例。采用《IMOCH婴幼儿高危因素评分表》结合新生儿住院期间病历记录,对高危儿的危险因素进行收集。结果高危儿在新生儿期的发生率为78%,其中危险因素百分率从高到低(10%)的依次排序为:新生儿期患感染性疾病:如肺炎等(51.28%)、胎龄37周(47.56%)、新生儿病理性黄疸(22.69%)、新生儿期出现呼吸障碍青紫现象(22.43%)、新生儿期出现易激惹尖叫现象(18.08%)、听力筛查异常(14.62%)、新生儿缺血缺氧性脑病(12.05%),并以单种因素(33.29%)和两种因素合并(32.53%)为主,且新生儿缺血缺氧性脑病、新生儿惊厥和新生儿期出现易激惹尖叫现象与高危儿出生胎龄正相关(P0.05),新生儿出现呼吸障碍青紫现象与高危儿出生胎龄负相关(P0.05)。结论高危儿在新生儿期的危险因素是多种的,各因素间相互作用相互影响,并且部分因素与出生胎龄也密切相关。     

小于胎龄早产儿产时胎心电子监护图形特征及其临床意义

目的探讨小于胎龄早产儿胎心电子监护图形(CTG)特征及其临床意义。方法回顾性分析303例32~36孕周、无妊娠合并症的单纯胎膜早破和原因不明早产孕妇的全产程CTG。其中,小于胎龄早产儿78例(PSGA组),适于胎龄早产儿225例(PAGA组)。比较宫缩时两组CTG特征,合并症情况及分娩结局。结果PSGA组及PAGA组出现单纯U型变异减速的胎儿分别为24例(308%)和10例(44%),两组比较,差异有统计学意义(P<001);U型变异减速合并其他异常CTG的胎儿分别为10例(128%)和1例(04%),两组比较,差异也有统计学意义(P<001)。PSGA组,出现单纯U型变异减速者的难产率(208%)与胎心电子监护无异常者的难产率(227%)比较,差异无统计学意义(P>005),但与U型变异减速合并其他异常CTG者的难产率(600%)比较,差异有统计学意义(P<005)。PSGA组中,34例出现U形变异减速,其中合并脐带异常15例(绕颈、绕身14例、脐带过短1例),PSGA组44例无U形变异减速者中,合并脐带异常9例(绕颈、绕身),两组比较,差异有统计学意义(P<005)。结论U形变异减速是小于胎龄早产儿分娩过程中的特征性胎儿监护图形,但不是胎儿缺氧的征象,如不合并其他异常CTG,不需特殊处理。     

Decreased cerebrovascular resistance in small for gestational age infants

Using a transcutaneous Doppler technique we found a significantly lower cerebrovascular resistance and higher cerebral blood flow velocity indicating vasodilatation and increase of cerebral blood flow in small for gestational age infants compared with appropriate for gestational age infants during the first days of life. We speculate that these findings are due to a continuation of the fetal situation in which chronic hypoxia, mostly caused by pregnancy-induced hypertension, possibly causes a prostacyclin-induced vasodilatation.     

Perinatal correlates and neonatal outcomes of small for gestational age infants born at term gestation

OBJECTIVE: We sought to examine the current perinatal correlates and neonatal morbidity associated with intrauterine growth failure among neonates born at term gestation. STUDY DESIGN: We compared 372 small for gestational age (SGA, birth weight <10th percentile) infants born at term gestation to 372 appropriate for gestational age controls (AGA, birth weight 10th to 90th percentile) matched by sex, race, and gestational age within 2 weeks. RESULTS: Compared with AGA controls, significant (P < .05) maternal risk factors for SGA status included single marital status (59% versus 53%), lower prepregnancy weight (144 +/- 41 lbs versus 153 +/- 40 lbs), lower weight gain during pregnancy (29 +/- 15 lbs versus 33 +/- 15 lbs), smoking (25% versus 17%), hypertension (14% versus 7%), and multiple gestation (9% versus 2%). Mothers of SGA infants were more likely to undergo multiple (>or=3) antenatal ultrasound evaluations (19% versus 7%), biophysical profile monitoring (11% versus 4%), and oxytocin delivery induction (28% versus 16%) (P < .05). Pediatrician attendance was more common among SGA deliveries (50% versus 37%, P < .05). SGA infants had significantly higher rates of hypothermia (18% versus 6%) and symptomatic hypoglycemia (5% versus 1%). These neonatal problems remained significant even when medical or pathologic causes of intrauterine growth failure, including pregnancy hypertension, multiple gestation, and congenital malformations, were excluded. CONCLUSION: Despite higher rates of pregnancy complications among mothers of SGA infants, the rates of neonatal adverse outcomes are low. However, SGA infants remain at risk for hypothermia and hypoglycemia and require careful neonatal surveillance.     

Pathology of placenta from small for gestational age infants

Pathologic study was carried out in 125 placentas, of which 25 were from cases of small for gestational age infants (SGA) and 100 from normal pregnancies. Ultrastructural study was done in 5 cases of each group. In the SGA group placenta circumvallata and velamentous insertion of cord were more frequently seen and the percentages of syncytial knots, cytotrophoblastic cells, and fibrinoid necrosis, stromal fibrosis and obliterative endarteritis of chorionic villi were also higher. Deficiency of vasculo-syncytial membranes and unduly thick trophoblastic basement membranes were common features of the SGA placentas. The most significant ultrastructural finding was the spasticity of capillaries of the villous stroma. It is believed that insufficient utero-placental blood flow may lead to the occurrence of SGA infants.     

Clinical outcome of small for gestational age preterm infants

Data from 55 preterm SGA infants and 55 preterm AGA infants matched for gestational age and sex were reviewed retrospectively. An increased incidence of perinatal hypoxia (30 vs. 18), gastrointestinal problems, minor infections (27 vs. 9), hematological problems and increased mortality (21.8% vs. 7.2%) was observed in the SGA infants. The incidence of HMD was higher in the AGA group (not significant), but the HMD was much more severe in the SGA group. Mortality as a result of HMD was significantly higher in the SGA group. The percentage of handicapped children is 19% in the SGA group and 9% in the AGA group. The percentages of severely handicapped children are 4.8% and 2.3% respectively. The combination of prematurity and severe intrauterine growth retardation in the SGA group caused a higher mortality and morbidity than was seen in their AGA controls. This clinical performance of SGA preterm infants is important especially for those who have to decide at what moment such a child should be delivered by caesarean section.     

Plasma adrenomedullin levels in pregnancies with appropriate for gestational age and small for gestational age infants.

AIMS: To evaluate whether maternal and fetal plasma adrenomedullin levels in pregnancies with small for gestational age (SGA) infants are different from those in pregnancies with appropriate for gestational age (AGA) infants. METHODS: Maternal and fetal circulating adrenomedullin levels were compared between 62 pregnancies with AGA (43 delivered vaginally and 19 delivered by elective cesarean section) and 28 pregnancies with SGA (20 delivered vaginally and 8 delivered by elective cesarean section) at birth. Plasma adrenomedullin levels were measured from maternal and cord venous blood samples using a radioimmunoassay. Umbilical artery blood pH was also measured. RESULTS: There were no significant differences for maternal total adrenomedullin levels, mature adrenomedullin levels, and its ratio among the groups. There were also no significant differences for fetal total adrenomedullin levels, mature adrenomedullin levels, and its ratio among the groups. In the AGA group delivered vaginally, fetal mature/total adrenomedullin ratio (mean +/- standard error, 16.6 +/- 0.7%) was significantly higher than the maternal ratio (13.8 +/- 0.6%) (p < 0.05). In the SGA group delivered vaginally, fetal mature/total adrenomedullin ratio (18.5 +/- 1.0%) was also significantly higher than the maternal ratio (14.5 +/- 0.6%) (p < 0.05). There was no significant difference in umbilical artery blood pH among the groups. CONCLUSIONS: These results suggest that maternal and fetal plasma circulating adrenomedullin levels may play a role in maternal and fetal cardiovascular adaptation during delivery in pregnancies with both AGA and SGA infants.     

Renal function is impaired in small for gestational age premature infants

Objectives: Small for gestational age (SGA) premature infants are at increased risk for complications. We aimed to evaluate if SGA infants are at higher risk for presenting renal insufficiency in the newborn period compared to appropriate for gestational age (AGA) premature infants. Methods: We conducted a retrospective case-control study of infants ≤ 34 weeks gestation. Markers of renal function based upon the Acute Kidney Injury Network were compared between both groups. Results: Twenty SGA infants were compared to twenty AGA infants matching in sex and gestational age. SGA infants had higher serum creatinine on day of life (DOL) 1 (p = 0.014) and DOL 3 (p = 0.05) and a higher overall maximum creatinine concentration (p = 0.013). They were also more likely to have an increase in serum creatinine more than 0.3?mg/dL in a 48-h period (OR: 7.8, p = 0.008) and increase in serum creatinine more than 50% in a 48-h period (OR: 12.4, p = 0.002). Urine output (mL/kg/h) was significantly less in the SGA group on DOL 3 (p = 0.002) and DOL 7 (p = 0.017). Conclusions: SGA infants are at increased risk for renal insufficiency during the neonatal period, thereby implying the need for special considerations in their fluid and medication management.     

Brainstem conduction time abnormalities in small for gestational age infants.

Brainstem auditory evoked responses (BAER) were recorded in 89 neonates born between 32 and 40 weeks, in order to analyze the consequences of intrauterine growth retardation on brainstem conduction time. The I-V interval was measured in 28 appropriate for gestational age (AGA) infants (control group), in 24 small for gestational age (SGA) infants with maternal hypertensive disease (MHD) and in 37 SGA infants without MHD. At any gestational age, SGA infants with MHD always presented an acceleration of their brainstem conduction time as compared to the other SGA infants. For the SGA full-term twins without MHD, the brainstem conduction time was delayed. These results reflect the specific consequences on brainstem development of the various factors responsible for intrauterine growth retardation (IURG).     

Comparison of late-second-trimester nonstress test characteristics between small for gestational age and appropriate for gestational age infants

OBJECTIVE: To compare electronic fetal heart rate (FHR) monitoring characteristics between appropriate for gestational age (AGA) fetuses and small for gestational age (SGA) fetuses and to determine whether SGA fetuses have specific abnormalities at second-trimester electronic fetal monitoring (EFM), using nonstress test. METHODS: Among 953 children born from 1993-1996, we identified 500 singleton infants born after 36 weeks' gestation of uncomplicated pregnancies in whom second-trimester (24-27 weeks' gestation) EFM records were obtained. Individual components of FHR patterns (baseline rate, baseline FHR variability, presence of acceleration [at least 10 beats per minute for at least 10 seconds], and periodic or episodic deceleration [at least 25 beats per minute for at least 15 seconds]) and birth characteristics were compared between AGA and SGA infants, or between pregnancies with or without second-trimester decelerations. RESULTS: Among 500 infants, 443 were AGA and 57 SGA; 105 had and 395 did not have second-trimester decelerations. Baseline FHR variability (12.9+/-3.2 beats per minute) in SGA fetuses was significantly higher than variability (10.3+/-3.4 beats per minute) in AGA fetuses (P<.001). Small for gestational age fetuses were significantly more likely to have second-trimester decelerations than AGA fetuses (33.3% vs. 19.4%, P<.05). There were no significant differences in baseline rate and accelerations between AGA and SGA infants. Small for gestational age infants were more frequent in pregnancies with second-trimester decelerations, compared with those without second-trimester decelerations (18.1% vs. 9.6%, P<.05). Baseline FHR variability in pregnancies with second-trimester decelerations was significantly higher than in pregnancies without second-trimester decelerations (12.2+/-3.7 vs. 10.0+/-3.1 beats per minute, P<.001). CONCLUSION: Periodic or episodic decelerations and increased FHR variability during late second-trimester EFM were associated with an increased risk of SGA birth weight.     

Neonatal outcomes of small for gestational age preterm infants in Canada

To compare the effect of small for gestational age (SGA) on mortality, major morbidity and resource utilization among singleton very preterm infants (<33 weeks gestation) admitted to neonatal intensive care units (NICUs) across Canada. Infants admitted to participating NICUs from 2003 to 2008 were divided into SGA (defined as birth weight <10th percentile for gestational age and sex) and non-small gestational age (non-SGA) groups. The risk-adjusted effects of SGA on neonatal outcomes and resource utilization were examined using multivariable analyses. SGA infants (n = 1249 from a cohort of 11,909) had a higher odds of mortality (adjusted odds ratio [AOR] 2.46; 95% confidence interval [CI], 1.93-3.14), necrotizing enterocolitis (AOR 1.57; 95% CI, 1.22-2.03), bronchopulmonary dysplasia (AOR 1.78; 95% CI, 1.48-2.13), and severe retinopathy of prematurity (AOR 2.34; 95% CI, 1.71-3.19). These infants also had lower odds of survival free of major morbidity (AOR 0.50; 95% CI, 0.43-0.58) and respiratory distress syndrome (AOR 0.79; 95% CI, 0.68-0.93). In addition, SGA infants had a more prolonged stay in the NICU, and longer use of ventilation continuous positive airway pressure, and supplemental oxygen (p < 0.01 for all). SGA infants had a higher risk of mortality, major morbidities, and higher resource utilization compared with non-SGA infants.     

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.     

Fewer accelerations and decreased long term variability in the heart rate of small for gestational age fetuses.

Two hundred newborns delivered after decelerative antenatal fetal heart rate tracings were divided retrospectively into two groups, one that was small for gestational age (SGA) and another that was appropriately grown for gestational age (AGA). Analysis of the tests showed a lower prevalence of good long term variability in the SGA group when compared with the AGA group. In addition, fetal heart rate accelerations occurred less frequently in the SGA group, even in the presence of good long term variability.     

Placental vascularization in early onset small for gestational age and preeclampsia

The objective was to determine whether chorionic villous vascularization is diminished in cases of early onset (<34 weeks) small for gestational age (SGA) and/or preeclampsia (PE). Placental morphometrical measurements were performed in 4 gestational-age-matched groups complicated by SGA, SGA with PE, PE, and spontaneous preterm delivery without SGA or PE as the reference group. Using a video image analysis system, in randomly selected intermediate and terminal villi, the stromal area and the following villous vascular parameters were manually traced and analyzed: number of total, centrally and peripherally localized vessels, vascular area, and vascular area density. No differences were observed in intermediate and terminal villous vascular area. Preeclampsia was associated with smaller terminal villous stromal area (reference 2299 μm2, SGA 2412 μm2, SGA + PE 2073 μm2, and PE 2164 μm2, P = .011), whereas SGA was associated with an increased terminal villous vascular area density (reference 26.1%, SGA 35.7%, SGA + PE 33.4%, and PE 32.0%, P = .029). Compared with preserved flow, lower terminal villous vascular area density was found in cases with absent or reversed end-diastolic (ARED) umbilical artery flow (39.3% vs. 30.3%, P = .013). These data demonstrate that villous vascularization was not influenced by PE, whereas in terminal villi an increased vascular area density was associated with SGA. Lower terminal villous vascular area density was associated with ARED flow in SGA pregnancies, indicating an increased risk of fetal compromise.     

Obstetric characteristics and neonatal performance in a four-year small for gestational age population

Obstetric and neonatal performance were analyzed in an ultrasound-dated small for gestational age (SGA) population from 1982-1985. Eighty-three percent of 160 SGA infants were identified antenatally by means of intrauterine growth retardation (IUGR) risk scoring, and the pregnancies were supervised at a high-risk clinic. Fifty percent were delivered electively, predominantly in gestational weeks 38-39. Thirty percent were born preterm. The cesarean section rate was 40%. Perinatal mortality was 6%, or 4% when lethal malformations were excluded, ten times higher than the corresponding total population figures. Eleven percent of the fetuses had severe malformations. In the remaining SGA population, one infant died after experiencing severe perinatal asphyxia and another developed cerebral palsy; no other major sequelae were found before the age of 18 months. Hypoglycemia and hypothermia occurred frequently, but these problems were managed satisfactorily. The mean hospital stay for term infants was twice that of appropriate for gestational age infants. We conclude that the extra attention paid to the SGA population is well motivated. Future efforts should be directed toward improving the diagnostic techniques for IUGR, as most of the perinatal mortality occurred among SGA infants not identified before birth.