Why babies don't drown at birth?

Oxytocin and Vasopressin, and the GABA Developmental Shift During Labor and Birth: Friends or Foes?

Oxytocin (OT) and vasopressin (AVP) are usually associated with sociability and reduced stress for the former and antidiuretic agent associated with severe stress and pathological conditions for the latter. Both OT and AVP play major roles during labor and birth. Recent contradictory studies suggest that they might exert different roles on the GABA excitatory/inhibitory developmental shift. We reported (Tyzio et al., 2006) that at birth, OT exerts a neuro-protective action mediated by an abrupt reduction of intracellular chloride levels ([Cl-]i) that are high in utero, reinforcing GABAergic inhibition and modulating the generation of the first synchronized patterns of cortical networks. This reduction of [Cl-]i levels is abolished in rodent models of Fragile X Syndrome and Autism Spectrum Disorders, and its restoration attenuates the severity of the pathological sequels, stressing the importance of the shift at birth (Tyzio et al., 2014). In contrast, Kaila and co-workers (Spoljaric et al., 2017) reported excitatory GABA actions before and after birth that are modulated by AVP but not by OT, challenging both the developmental shift and the roles of OT. Here, I analyze the differences between these studies and suggest that the ratio AVP/OT like that of excitatory/inhibitory GABA depend on stress and pathological conditions.

Confounding with familial determinants affects the association between mode of delivery and childhood asthma medication - a national cohort study

Background

Mode of delivery may affect the risk of asthma but the findings have not been consistent and factors shared by siblings may confound the associations in previous studies.

Methods

The association between mode of delivery and dispensed inhaled corticosteroid (ICS) (a marker of asthma) was examined in a register based national cohort (n=199 837). A cohort analysis of all first born children aged 2-5 and 6-9 years was performed. An age-matched sibling-pair analysis was also performed to account for shared genetic and environmental risk factors.

Results

Analyses of first-borns demonstrated that elective caesarean section was associated with an increased risk of dispensed ICS in both 2-5 (adjusted odds ratio (aOR)=1.19, 95% confidence interval (CI) 1.09-1.29) and 6-9 (aOR=1.21, 1.09-1.34) age groups. In the sibling-pair analysis, the increased risk associated with elective caesarean section was confirmed in 2-5 year olds (aOR=1.22, 1.05-1.43) but not in 6-9 year olds (aOR=1.06, 0.78-1.44). Emergency caesarean section and vacuum extraction had some association with dispensed ICS in the analyses of first-borns but these associations were not confirmed in the sibling-pair analyses.

Conclusions

Confounding by familial factors affects the association between mode of delivery and dispensed ICS. Despite this confounding, there was some evidence that elective caesarean section contributed to a modestly increased risk of dispensed ICS but only up to five years of age.

Risk factors of neonatal respiratory distress following vaginal delivery and caesarean section in the German population

BACKGROUND

The incidence of caesarean section (CS) is steadily rising world-wide. In particular, CS on maternal demand is performed more frequently. In parts, this might be due to insufficient information of pregnant women about neonatal risks of CS. We sought to specify neonatal outcomes following different modes of delivery, i.e. vaginal delivery, primary CS and secondary CS and to define risk factors for respiratory morbidity and hospitalization.

METHODS

We analysed 2073 births (gestational age > 35 weeks) during a two-year period at a tertiary obstetric and neonatal centre in Germany. Statistical analyses were performed for single parameters by SPSS as well as by logistic regression to account for possible confounders. Furthermore, extensive model calculation was done.

RESULTS

Respiratory morbidity was increased following primary and secondary CS (p = 0.001). By multiple logistic regression, the strongest effect on respiratory symptoms was seen with gestational age, each week more in utero reducing the risk by an odds ratio (OR) of 0.69 (95% CI: [0.61; 0.79]; p = 1.9 x 10(-8)). Furthermore, a significant interaction between mode of delivery and gestational age was found for the risk of respiratory symptoms (p = 0.0035).

CONCLUSION

For every eight newborns delivered by primary CS one more than expected with vaginal delivery is hospitalized. It is highly relevant to recognize that each week of gestational age reduces the risk of respiratory symptoms, especially if primary CS is performed. The higher rate of respiratory morbidity and neonatal admission following CS should be clearly recognized in counselling of pregnant women.