Respiratory Morbidity in Late Preterm and Term Babies Born by Elective Caesarean Section

ObjectiveThis study sought to determine the incidence and severity of respiratory morbidity among late preterm and term babies born by elective Caesarean section (CS) in London, Ontario.MethodsA retrospective chart review was conducted of all elective CSs performed at or beyond 36⁰ weeks gestation from June 2010 to June 2014 at London Health Sciences Centre and St. Joseph's Health Care (Canadian Task Force Classification II-2).ResultsThe main indications for elective CS were previous CS (59.3%) and malpresentation (24.2%). The majority of elective CSs were performed at 38 weeks (34.1%) and 39 weeks (40.1%). Although only 3.7% of babies born by elective CS were found to have respiratory morbidity, 85% of these babies were admitted to the neonatal intensive care unit (NICU), and 15% required additional observation through a triage period. The relative risk of respiratory morbidity with elective CS at ≤38⁶ weeks compared with ≥39⁰ weeks was 2.14 (P = 0.0110). Only 3.5% of patients received antenatal steroids. There was an increased level of intervention among the babies admitted to the NICU for respiratory morbidity; 47.8%, 19.6%, 60.8%, and 15.25% required oxygen supplement, bag and mask, continuous positive airway pressure, and intubation with mechanical ventilation, respectively.ConclusionThe risk of respiratory morbidity was significantly higher following elective CS before 39 weeks gestation. This resulted in increased length of stay and increased requirements for intravenous lines, blood draws, and exposure to antibiotics. This study provides further evidence that uncomplicated elective CS should be performed at ≥39 weeks, and interventions, such as preoperative antenatal steroid administration, may be considered if elective CS is medically indicated before 39 weeks.     

Neonatal morbidity after cesarean section before labor at 34+0 to 38+6 weeks: a cohort study

Objective: To describe morbidity in neonates born by cesarean section (CS) before labor between 34⁺⁰ and 38⁺⁶ weeks, stratified by gestational age.

Methods: Cohort study from five Italian tertiary care hospitals. Consecutive singleton pregnancies delivered by CS before labor between 34⁺⁰ and 38⁺⁶ weeks of gestation from January 2010 to August 2011 were included. Women in labor, with premature rupture of membranes, or with previous administration of steroids were excluded. The incidence of neonatal complication by gestational week was calculated.

Results: A total of 1135 cases were analyzed. Composite adverse neonatal outcomes, respiratory distress syndrome, transient tachypnea and use of continuous airway positive pressure decreased from 50%, 28%, 5% and 22% at 34 weeks of gestation, to 4.7%, 1.0%, 0.9% and 0.3% at 38 weeks of gestation. Multivariate analysis showed that the only variable independently associated with composite adverse neonatal outcome was gestational age at delivery (adjusted odds ratio 0.49; 95% confidence interval 0.39–0.61).

Conclusions: The prevalence of neonatal complications in newborns delivered by CS before labor halves at each week of gestation from 34 to 38 weeks. Nonetheless complications, and mainly respiratory problems, are still present at early term gestation.     

Respiratory transition in infants delivered by cesarean section

One of the biggest challenges a newborn faces after birth is the task of making a smooth transition to air breathing. This task is complicated by the fact that fetal lungs are full of fluid which must be cleared rapidly to allow for gas exchange. Respiratory morbidity as a result of failure to clear fetal lung fluid is not uncommon, and can be particularly problematic in some infants delivered by elective cesarean delivery (ECS). Given the high rates of cesarean deliveries in the USA and worldwide, the public health and economic impact of morbidity in this subgroup is considerable. Whereas the occurrence of birth asphyxia, trauma, and meconium aspiration is reduced by elective Cesarean delivery, the risk of respiratory distress secondary to transient tachypnea of the newborn, surfactant deficiency, and pulmonary hypertension is increased. It is clear that physiologic events in the last few weeks of pregnancy coupled with the onset of spontaneous labor are accompanied by changes in the hormonal milieu of the fetus and its mother, resulting in preparation of the fetus for neonatal transition. Rapid clearance of fetal lung fluid is a key part of these changes, and is mediated in large part by transepithelial Na reabsorption through amiloride-sensitive Na channels in the alveolar epithelial cells, with only a limited contribution from mechanical factors and Starling forces. This chapter discusses the physiologic mechanisms underlying fetal lung fluid absorption and explores potential strategies for facilitating neonatal transition when infants are delivered by ECS before the onset of spontaneous labor.     

Relationship between thyroid hormone levels and transient tachypnea of the newborn in late-preterm,early-term,and term infants

Purpose: We aimed to investigate the association between thyroid hormone levels and transient tachypnea of the newborn (TTN) among late-preterm, early-term, and term infants admitted to neonatal intensive care unit (NICU).

Materials and method: In the current retrospective study, neonates admitted to the NICU due to TTN were assigned to the TTN group (n?=?404). Healthy neonates who were followed up in the well-baby nursery comprised the control group (n?=?7335). Infants were grouped by gestational age into late-preterm (34–36⁶ weeks), early-term (37–38⁶ weeks), and term subgroups (39–41⁶ weeks). Serum levels of thyroid-stimulating hormone (TSH) and thyroxin (T₄) were determined from venipuncture samples taken at least 48?hours after birth. The relationship between thyroid hormone levels and the need for NICU admission for TTN was compared between groups.

Results: Compared to control infants, term neonates with TTN had significantly higher TSH levels, whereas late-preterm and early-term neonates with TTN had significantly lower T₄ levels. Birth weight and mode of delivery had no effect on NICU admission for TTN.

Conclusions: Infants admitted to NICU due to TTN had significantly different thyroid hormone levels with differences depending on gestational age.     

Early rescue Neopuff for infants with transient tachypnea of newborn: a randomized controlled trial

Objective: To examine the efficacy of early continuous positive airway pressure (CPAP), delivered using a T-piece-based infant resuscitator (Neopuff) via a face mask, in reducing the severity and duration of transient tachypnea of the newborn (TTN) as well as testing a hypothesis suggesting that rapid clearance of fetal lung fluid to the circulation via CPAP would increase plasma B-type natriuretic peptide (BNP).

Methods: A randomized controlled trial (NCT01859533) was conducted on 64 late preterm/term neonates, delivered by cesarean section and presented by respiratory distress shortly after birth. The Neopuff group included 34 neonates received 20?min of early CPAP and control group included 30 neonates received free flow O₂. Plasma BNP was measured baseline and 2?h later.

Results: The duration of tachypnea was shorter in Neopuff group with less need of neonatal intensive care unit admission and need of mechanical support (p?p?>?.05). Plasma BNP showed no significant difference between pre- and post-Neopuff levels (p?>?.05). A positive correlation was found between BNP and duration of tachypnea as well as the length of hospitalization (p?Conclusion: Early rescue CPAP reduces the duration and severity of respiratory distress among infants with TTN.

Trial registration: ClinicalTrials.gov identifier: NCT01859533.     

Health,Physical Growth,and Neurodevelopmental Outcomes in Preterm Infants of Women With Hypertensive Disorders of Pregnancy

Objective

To compare the health, physical growth, and developmental outcomes in preterm infants of women with and without hypertensive disorders of pregnancy (HDP).

Relationship between the cortisol levels in umbilical cord blood and neonatal RDS/TTN in twin pregnancies

Objective: Twin neonates have a higher risk of respiratory complications, such as respiratory distress syndrome (RDS) and transient tachypnea of the newborn (TTN), than singleton neonates. The purpose of this study was to evaluate the relationship between the cortisol levels in the umbilical cord and neonatal RDS/TTN in twin pregnancies.

Methods: We analyzed data obtained from 106 neonates (53 twin pairs), comprising 33 dichorionic twin (DCT) and 20 monochorionic twin (MCT) gestations. All infants were delivered via scheduled cesarean section without labor. We measured the cortisol levels in umbilical vein blood using enzyme-linked immunosorbent assay.

Results: The cortisol levels in the umbilical vein were significantly lower in the RDS/TTN group than in the no RDS/TTN group (p = 0.004). The umbilical cortisol levels in the TTN group were between the values observed in the RDS group and no RDS/TTN group. We subsequently analyzed the cut-off cortisol values for RDS/TTN and observed higher accuracy in the DCTs than in the MCTs.

Conclusions: Neonates who develop RDS/TTN have significantly lower cortisol levels in the umbilical cord at birth than no RDS/TTN neonates in twin pregnancies. When applying these data in clinical practice, physicians should pay attention to differences based on chorionicity.     

产前多疗程与单疗程肾上腺糖皮质激素治疗对早产儿影响的Meta 分析

目的 综合评价产前多疗程与产前单疗程肾上腺糖皮质激素治疗对早产儿的有效性和安全性。方法 对满足条件的7篇有关产前肾上腺糖皮质激素治疗对早产儿影响的队列研究进行Meta分析。结果 产前多疗程肾上腺糖皮质激素治疗可降低早产儿动脉导管未闭(PDA)的发病率(OR=0．51，95％CI0．49～0．54)，有使早产儿呼吸窘迫综合征(RDS)发生率降低的趋势(OR=0．72，95％CI0．49～1．07)。但可增加早产儿败血症的发生率(OR=1．62，95％CI1．07～2．44)，且不能降低早产儿颅内出血(ICH)(OR=0．65，95％CI0．37～1．15)、坏死性小肠结肠炎(NEC)(OR=1．30，95％CI0．79～2．12)和慢性肺疾病(CLD)(OR=0．94，95％CI0.59～1．49)的发生率及病死率(OR=1．07，95％CI0．42～2．75)，也不能使早产儿出生后肺表面活性物质(PS)的应用减少(OR=0．86，95％CI0．48～1．55)。结论 无法根据现有的Meta分析结果证明产前多疗程肾上腺糖皮质激素治疗比产前单疗程肾上腺糖皮质激素治疗更有效和危险性更小。