Impact of pre-eclampsia in extremely premature infants: Population-based study

Sex differences in growth and mortality in pregnancy-associated hypertension

BACKGROUND

It is hypothesized that male fetuses prioritize growth, resulting in increased mortality, whereas females reduce growth in the presence of adversity. Preeclampsia reflects a chronic condition, in which fetuses have the opportunity to adjust growth. If females reduce their growth in response to preeclampsia, but males attempt to maintain growth at the cost of survival, we predict that differences in birthweight between preeclamptic and non-preeclamptic pregnancies will be greater among females, whereas differences in mortality will be greater among males.

METHODS

We analysed data from the Centers for Disease Control and Prevention. We compared pregnancies with pregnancy-associated hypertension (PAH) and controls.

RESULTS

The difference in birthweight between pregnancies affected by PAH and controls varied by fetal sex and gestational age. Among pregnancies of White individuals, at 34-35 weeks, the difference between PAH and controls was higher among females, as predicted. However, this pattern was reversed earlier in pregnancy and around term. Such variation was not significant in Black pregnancies. In both Black and White pregnancies, early in gestation, males had lower odds of death in PAH pregnancies, but higher odds of death in control pregnancies, counter to our prediction. Later, males had higher odds of death in PAH and controls, although the increased odds of death in males was not higher in PAH pregnancies than in controls. Overall, the difference in birthweight between surviving and non-surviving infants was greater in males than in females, opposite to our prediction.

CONCLUSIONS

The impact of PAH on birthweight and survival varies widely throughout gestation. Differences in birthweight and survival between male and female PAH and controls are generally not consistent with the hypothesis that males prioritize fetal growth more than females, and that this is a cause of increased mortality in males.

Maternal hypertensive disorders and survival without major morbidities among extremely low gestation newborns

OBJECTIVE

Evaluate if odds of survival without major morbidity are higher among extremely low gestation neonates (ELGANs) born to mothers with chronic hypertension (cHTN) or hypertensive disorders of pregnancy (HDP) compared to ELGANs born to mothers without hypertension (HTN).

STUDY DESIGN

Retrospective study of prospectively collected data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network. Included children had a birthweight of 401-1000 g and/or gestational age of 220/7 to 286/7 wks. The primary outcome was survival to discharge without major morbidity. Multivariable regression models were used to compare outcomes among ELGANs born to women with cHTN, HDP, and no HTN.

RESULTS

Survival without morbidities for newborns of mothers with no HTN, cHTN and HDP (29.1%, 32.9%, 37.0% respectively) did not differ after adjustment.

CONCLUSION

After adjusting for contributing variables maternal HTN is not associated with improved survival free of morbidity among ELGANs.

TRIALS REGISTRATION

clinicaltrials.gov Identifier: NCT00063063 (generic database).

A Retrospective Cohort Study on Mortality and Neurodevelopmental Outcomes of Preterm Very Low Birth Weight Infants Born to Mothers with Hypertensive Disorders of Pregnancy

OBJECTIVE

We examined the effects of maternal hypertensive disorders of pregnancy (HDP) on the mortality and neurodevelopmental outcomes in preterm very low birth weight (VLBW) infants (BW ≤1,500 g) based on their intrauterine growth status and gestational age (GA).

STUDY DESIGN

We included singleton VLBW infants born at <32 weeks' gestation registered in the Neonatal Research Network Japan database. The composite outcomes including death, cerebral palsy (CP), and developmental delay (DD) at 3 years of age were retrospectively compared among three groups: appropriate for GA (AGA) infants of mothers with and without HDP (H-AGA and N-AGA) and small for GA (SGA) infants of mothers with HDP (H-SGA). The adjusted odds ratios (AOR) and 95% confidence intervals (CI) stratified by the groups of every two gestational weeks were calculated after adjusting for the center, year of birth, sex, maternal age, maternal diabetes, antenatal steroid use, clinical chorioamnionitis, premature rupture of membranes, non-life-threatening congenital anomalies, and GA.

RESULTS

Of 19,323 eligible infants, outcomes were evaluated in 10,192 infants: 683 were H-AGA, 1,719 were H-SGA, and 7,790 were N-AGA. Between H-AGA and N-AGA, no significant difference was observed in the risk for death, CP, or DD in any GA groups. H-AGA had a lower risk for death, CP, or DD than H-SGA in the 24 to 25 weeks group (AOR: 0.434, 95% CI: 0.202-0.930). The odds for death, CP, or DD of H-SGA against N-AGA were found to be higher in the 24 to 25 weeks (AOR: 2.558, 95% CI: 1.558-3.272) and 26 to 27 weeks (AOR: 1.898, 95% CI: 1.427-2.526) groups, but lower in the 30 to 31 weeks group (AOR: 0.518, 95% CI: 0.335-0.800).

CONCLUSION

There was a lack of follow-up data; however, the outcomes of liveborn preterm VLBW infants of mothers with HDP depended on their intrauterine growth status and GA at birth.

KEY POINTS

· The effects of HDP on preterm low birth weight infants need to be further examined.. · The outcomes were not different between AGA infants with and without maternal HDP.. · The outcomes of SGA infants with maternal HDP were dependent on their GA..

Impact of hypertensive disorders of pregnancy on respiratory outcomes in extremely and very preterm infants: A population-based study in Japan

OBJECTIVES

We aimed to evaluate the impact of hypertensive disorders of pregnancy (HDP) on short- and medium-term respiratory outcomes in extremely and very preterm infants using the Neonatal Research Network of Japan database.

STUDY DESIGN

This was a population-based retrospective study of preterm infants weighing ≤ 1500 g born between 22 and 31 weeks of gestation between 2003 and 2017. After 1:1 stratification matching by four factors (maternal age, gestational age, parity, and year of delivery), a total of 5137 infants in each group (HDP and non-HDP groups) were selected.

MAIN OUTCOME MEASURES

The association between HDP and various respiratory outcomes was evaluated using univariate and multivariate logistic regression analyses.

RESULTS

In the multivariate analyses, HDP was associated with higher odds for respiratory distress syndrome (RDS) (odds ratio 1.83, 95% confidence interval [1.65-2.03]), but reduced odds of persistent pulmonary hypertension of the newborn (PPHN) (0.34 [0.26-0.46]) and inhaled nitric oxide use (0.43 [0.33-0.55]). Although HDP was associated with an increased risk of chronic lung disease (CLD) in the univariate analysis, this association was not significant after adjustment for covariates (0.94 [0.83-1.07]). No significant association was found between HDP and home oxygen therapy (HOT) and medium-term oxygen use.

CONCLUSION

The impact of maternal HDP largely differed depending on respiratory disorders and respiratory support. HDP was associated with higher odds of RDS but reduced odds of PPHN. The risks for CLD, HOT, and medium-term respiratory outcomes in the HDP group were comparable to those in the non-HDP group.

Adverse pregnancy outcomes among mothers with hypertensive disorders in pregnancy: A meta-analysis of cohort studies

BACKGROUND

Presently, the results of studies assessing the association of hypertensive disorders in pregnancy (HDP) with adverse pregnancy outcomes (APOs) in offspring remain inconclusive, and a complete overview is missing. We performed a meta-analysis of cohort studies to review and summarize the association between HDP and risk of APOs in offspring.

METHODS

PubMed, Embase, Web of Science and Chinese databases were searched through May 2019 to identify eligible studies. Outcomes of interest were APOs including perinatal death, fetal death, stillbirth, neonatal death, congenital malformations, preterm birth (PTB), very preterm birth (VPTB), intrauterine growth restriction (IUGR), small for gestational age (SGA), low birth weight (LBW), and very low birth weight (VLBW). Either a fixed- or a random-effects model was used to calculate the overall combined risk estimates. Subgroup analysis was performed to explore potential heterogeneity moderators.

RESULTS

Total 152 cohort studies involving 1,426,742 mothers with HDP and 36,374,542 mothers without HDP were included for analysis. Overall, mothers with HDP compared with those without HDP had a significantly higher risk of perinatal death (OR = 2.86), fetal death (OR = 2.82), stillbirth (OR = 1.93), neonatal death (OR = 1.55), congenital malformations (OR = 2.66), IUGR (OR = 5.48), SGA (OR = 3.39), LBW (OR = 5.02), VLBW (OR = 1.74), PTB (OR = 4.20) and VPTB (OR = 3.26) in offspring. Relevant heterogeneity moderators were identified by subgroup analyses. The sensitivity analysis yielded consistent results. No evidence of publication bias was observed.

CONCLUSION

The present study indicates that HDP significantly increases risk of APOs. Further research is needed to explore efficient management methods to minimize the risk of APOs associated with HDP.

SURVIVAL UNTIL DISCHARGE OF VERY-LOW-BIRTH-WEIGHT INFANTS IN TWO CROATIAN PERINATAL CARE REGIONS: A RETROSPECTIVE COHORT STUDY OF TIME AND CAUSE OF DEATH

We investigated mortality, causes, timing and risk factors for death until hospital discharge in very-low-birth-weight (VLBW) infants born in two Croatian perinatal care regions. This retrospective study included 252 live born VLBW infants. The mortality rate until hospital discharge was 30.5% (77/252). VLBW infants who died had by 4 weeks lower gestational age (GA) than surviving infants (median GA, 25 vs. 29 weeks), lower birth weight (BW) (mean BW, 756.4 vs. 1126.4 g), lower 5-minute Apgar score (median 5 vs. 8) and were more often resuscitated at birth (41.6 vs. 19.4%; p<0.001 all). Infants who survived were more often small-for-gestational age (SGA) (28.0 vs. 15.6%; p=0.04) and more often received continuous-positive-airway-pressure (CPAP) in delivery room (13.1 vs. 2.6%; p=0.01). Multivariate logistic regression revealed that parameters influencing death until hospital discharge were 5-minute Apgar score (OR 0.780, 95% CI 0.648-0.939) and higher Clinical Risk Index for Babies (CRIB) score (OR 1.677, 95% CI 1.456-1.931). ROC analysis showed that CRIB score (AUC 0.927, sensitivity 92.2, specificity 81.1; p<0.001) was the strongest predictor of death until hospital discharge. In infants who died within 12 hours, death was most commonly attributed to immaturity and in those surviving >12 hours to necrotizing enterocolitis.

Maternal hypertension and survival in singletons and twins born at 23-29 weeks: not just one answer…

BACKGROUND

To describe the association between maternal hypertension (chronic and gestational, MH) and mortality in very preterm singletons and twins, focusing on how estimates depend on gestational age (GA) and size at birth.

METHODS

We estimated relative risks of in-hospital death in 12,320 singletons (MH: 22.4%) and 4381 twins (MH: 10.6%) born at 23-29 weeks in the Italian Neonatal Network (89 hospitals, 2008-2016).

RESULTS

Babies with MH had higher GA and were more frequently small-for-gestational age (SGA), especially singletons. In crude analyses, MH was associated with lower mortality in singletons. In multivariable analyses, the effects of GA and size differed between twins and singletons with and without MH. The best-fitting models included continuous birth weight (rather than SGA) and were stratified by GA. In these models, MH was associated with lower mortality in singletons-but not twins-born after week 25.

CONCLUSIONS

In this cohort of very preterm infants, the association between MH and mortality differed between singletons and twins and across strata of GA at birth. These estimates cannot be interpreted causally, but suggest that, from a descriptive/predictive standpoint, singletons with MH born after week 25 have lower mortality than singletons born to women without MH.

Variations in Umbilical Cord Hematopoietic and Mesenchymal Stem Cells With Bronchopulmonary Dysplasia

Objective: To test the hypothesis that umbilical cord blood-derived CD34+ hematopoietic stem cells (HPSC), cord tissue-derived CD90+ and CD105+ mesenchymal stem cells (MSC) vary with bronchopulmonary dysplasia (BPD). Methods: We conducted a prospective longitudinal study at a large birth center (Prentice Women's Hospital in Chicago, IL). Premature infants (N = 200) were enrolled in 2:1:1 ratio based on gestational age (GA): mildly preterm (31-32 weeks), moderately preterm (29-30 weeks), and extremely preterm (23-28 weeks). Cord blood (CB) and cord tissues (CT) were collected at birth using commercial banking kits, and analyzed for collection blood volume, tissue mass, CD34+, CD90+, CD105+ counts, and concentrations. Multiplex immunoassay was used to measure 12 cytokines and growth factors in CB plasma of 74 patients. BPD severity was defined according to NIH consensus definitions. Univariate and multivariate regression models were used to identify perinatal covariates and assess associations between stem cell concentrations, cytokines, and BPD outcomes. Results: Of 200 patients enrolled (mean GA = 30 ± 2 weeks), 30 developed mild, 24 moderate, and 19 severe BPD. Concentrations of HPSC and MSC, as measured by %CD34+, %CD90+, and %CD105+ of total cells, increased with degree of prematurity. Collection parameters varied with GA, birth weight (BW), gender, prolonged rupture of membranes, mode of delivery, chorioamnionitis, and multiple gestation. Moderate-severe BPD or death was increased with lower GA, BW, Apgar scores, and documented delayed cord clamping. %CD34+ and %CD90+ were increased with BPD and directly correlated with BPD severity. Severe BPD was positively associated with %CD34+ (beta-coefficient = 0.9; 95% CI = 0.4-1.5; P < 0.01) and %CD90+ (beta-coefficient = 0.4; 95% CI = 0.2-0.6; P < 0.001) after adjustment for covariates. CB plasma granulocyte-colony stimulating factor (G-CSF) was inversely associated with %CD90+, and decreased with BPD. Below median G-CSF combined with elevated %CD90+ predicted BPD (positive predictive value = 100%). Conclusions: CB and CT collections yielded high concentrations of HPSCs and MSCs in BPD infants, accompanied by low circulating G-CSF. These variations suggest possible mechanisms by which stem cell differentiation and function predict BPD.

Neonatal outcomes of very low birthweight infants born to mothers with hyperglycaemia in pregnancy: a retrospective cohort study in Japan

OBJECTIVE

To examine the mortality and morbidities of very low birthweight (VLBW, <1500 g) infants of mothers with hyperglycaemia in pregnancy.

DESIGN AND SETTING

We conducted a retrospective cohort study using data from the Neonatal Research Network of Japan, a nationwide registry of VLBW infants (2003-2012).

PATIENTS

We studied 29 626 infants born at 23 to 32 weeks without major congenital anomalies, of which 682 (2.3%) infants were from pregnancies affected by maternal hyperglycaemia.

MAIN OUTCOME MEASURES

The primary outcome was hospital mortality. Secondary outcomes were neonatal morbidities and their anthropometric values. Associations between maternal hyperglycaemia and each outcome were observed for the overall period, and statistical tests for interaction were conducted to assess whether they differed before or after the adoption of the International Association of Diabetes in Pregnancy Study Group (IADPSG) guidelines in 2010 for the diagnosis of gestational diabetes mellitus.

RESULTS

Overall, hospital mortality (4.1% vs 5.2%), composite outcomes of mortality and severe morbidity (54.2% vs 60%), and anthropometric values were not significantly different between infants of mothers with or without hyperglycaemia in pregnancy. However, the incidence of respiratory distress syndrome (RDS) in VLBW infants from mothers with hyperglycaemia was significantly higher than those from mothers without it only before (relative risk (RR) 1.09, 95% CI 1.00 to 1.19) and not after (RR 0.97, 95% CI 0.83 to 1.11) the adoption of the IADPSG guidelines.

CONCLUSION

VLBW infants born to mothers with hyperglycaemia in pregnancy do not seem to be at higher risk of mortality and morbidities, except for RDS only before the adoption of the IADPSG guidelines.

Preeclampsia predicts higher incidence of bronchopulmonary dysplasia

INTRODUCTION

It is not known whether very preterm infants born to preeclamptic women have worse outcomes than those delivered preterm for other causes.

OBJECTIVE

We assessed the association between preeclampsia (PE) and the neonatal morbidity and mortality of very preterm infants.

METHODS

Over 2015 and 2016, 11 collaborating Portuguese level III NICUs prospectively enrolled a cohort of mothers with or without PE who delivered liveborn premature infants between 24 and 30 completed weeks of gestation. Data on neonatal morbidities were collected and their association to PE was assessed.

RESULTS

The final cohort consisted of 410 mothers who delivered 494 preterm infants. Infants from PE mothers weighed less than those of non-PE mothers (819 ± 207 g vs. 989 ± 256 g, p < 0.0001). Incidences of respiratory distress syndrome, patent ductus arteriosus, early and nosocomial sepsis, necrotizing enterocolitis, pneumonia, meningitis, retinopathy of prematurity, intraventricular hemorrhage, periventricular infarction, periventricular leukomalacia, and mortality did not differ significantly between infants of PE or non-PE mothers. Incidence of bronchopulmonary dysplasia (BPD-defined as oxygen dependency at 36 weeks) was higher in PE infants compared with non-PE infants by both univariate and multivariate logistic regression (p = 0.007).

CONCLUSION

We conclude that, when controlling for gestational age, maternal PE results in higher incidence of only BPD among preterm Portuguese infants.

Pregnancy-induced hypertension and neonatal outcomes: a systematic review and meta-analysis

OBJECTIVE

Pregnancy-induced hypertension (PIH) is associated with preterm delivery but its independent impact on neonatal outcomes remains unclear. We sought to systematically review and meta-analyze clinical outcomes of preterm infants <37 weeks' gestation born to mothers with and without PIH.

STUDY DESIGN

Medline, Embase, PsychINFO and CINAHL were searched from January 2000 to October 2016. Studies with low-moderate risk of bias reporting neonatal outcomes based on PIH as primary exposure variable were included. Data were extracted independently by two co-authors.

RESULTS

PIH was associated with lower mortality (3 studies; adjusted odds ratio (aOR) 0.65; 95% confidence interval (CI) 0.54 to 0.79), lower severe retinopathy of prematurity (ROP) (2 studies; aOR 0.83; 0.72 to 0.96) and lower severe brain injury (2 studies; unadjusted OR (uOR) 0.57; 0.49 to 0.66). No association between PIH and short-term respiratory outcomes, bronchopulmonary dysplasia (BPD) or necrotizing enterocolitis (NEC) was identified. In subgroup analysis among infants <29 weeks' gestation, BPD odds were higher (3 studies; aOR 1.15; 1.06 to 1.26), whereas mortality lower (2 studies; aOR 0.73; 0.69 to 0.77). In subgroup analysis limited to severe PIH, odds of mortality (3 studies; uOR 2.36; 1.07 to 5.22) and invasive ventilation (3 studies; uOR 3.26; 1.11 to 9.61) were higher. In subgroup analysis limited to preeclampsia, odds of BPD (3 studies; uOR 1.21; 95% CI:1.03 to 1.43) and NEC were higher (3 studies; uOR 2.79; 95% CI:1.57 to 4.96).

CONCLUSION

PIH was associated with reduced odds of mortality and ROP (all infants), but higher odds for BPD (<29 weeks' gestation). The paradoxical reduction in mortality may be due to survival bias and deserves further exploration in future studies.