Effects of different modes of delivery on lung volumes of newborn infants

The health implications of birth by Caesarean section

Since the first mention of fetal programming of adult health and disease, a plethora of programming events in early life has been suggested. These have included intrauterine and postnatal events, but limited attention has been given to the potential contribution of the birth process to normal physiology and long-term health. Over the last 30 years a growing number of studies have demonstrated that babies born at term by vaginal delivery (VD) have significantly different physiology at birth to those born by Caesarean section (CS), particularly when there has been no exposure to labour, i.e. pre-labour CS (PLCS). This literature is reviewed here and the processes involved in VD that might programme post-natal development are discussed. Some of the effects of CS are short term, but longer term problems are also apparent. We suggest that VD initiates important physiological trajectories and the absence of this stimulus in CS has implications for adult health. There are a number of factors that might plausibly contribute to this programming, one of which is the hormonal surge or "stress response" of VD. Given the increasing incidence of elective PLCS, an understanding of the effects of VD on normal development is crucial.

Neonatal respiratory morbidity after elective cesarean section

OBJECTIVE

The objective of this study was to examine the rate of respiratory morbidity in neonates delivered by elective cesarean delivery (ECD) at term, with a definite confirmation of gestational age (GA) by 1st-trimester ultrasound.

METHODS

Consecutive women carrying a singleton pregnancy and undergoing ECD at term (>38 1/7 weeks), confirmed by 1st-trimester ultrasound, were included in the study group. Multiple gestations, cesarean section (CS) in labor, CS performed after rupture of membranes and induced deliveries were excluded. The control group included women with a singleton pregnancy at term (>38 1/7 weeks) who delivered spontaneously. This group of women was randomly selected during the study period.

RESULTS

The study group included 277 women delivered by ECD. The control group consisted of 311 women. Five newborns in the study group and none in the control group were admitted to the neonatal intensive care unit (NICU) due to respiratory disorders (p < 0.02). Excluding diabetic women did not change the results. On multivariate analysis, no other factors were found to independently influence the risk of respiratory complications.

CONCLUSION

In our study, the rate of respiratory morbidity was found to be significantly higher in neonates delivered by ECD compared to those delivered vaginally. The fact that GA was confirmed by 1st-trimester ultrasound makes iatrogenic prematurity an unlikely sole cause for this excess morbidity.

Incidence and etiology of pelvic floor dysfunction and mode of delivery: an overview

Elective cesarean section at patient request is becoming common place. Women are requesting the intervention for preservation of the pelvic floor, but there is conflicting evidence to suggest that this mode of delivery has such benefits. The risks vs. benefits of both vaginal delivery and cesarean section need to be well understood before deciding on a surgical delivery. This review outlines the current available evidence of the risks and benefits associated with vaginal delivery and elective cesarean section and the incidence and mechanisms of injury that lead to pelvic floor dysfunction. As in most surgical conditions, a better understanding of causality of pelvic floor dysfunction may help treatment effectiveness.

Patient choice cesarean: an evidence-based review

Primary elective cesarean performed on a patient's request now comprises 4% to 18% of all cesareans and 14% to 22% of elective cesareans in reported series. Patients most commonly choose cesarean because of tocophobia, or fear of childbirth. Almost two thirds of obstetricians surveyed are willing to perform cesarean on request, citing decreased risk of pelvic floor or fetal injury, maintenance of sexual functioning, and physician and patient convenience. Contrasting these beliefs are the limited available data on short- and long-term maternal and perinatal morbidity and mortality that generally favor vaginal delivery. Moreover, comprehensive economic impact assessments of cesarean on request are lacking, and professional organizations do not agree on the ethics of offering patient choice cesarean.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to list the reasons that women and obstetricians choose elective cesarean delivery, to outline the ethical aspects of cesarean delivery, and to describe the material and fetal morbidity and mortality associated with cesarean delivery compared to vaginal delivery.

Optimal timing of elective caesarean section in Belgian White and Blue breed of cattle: the calf's point of view

The purpose of this study was to evaluate whether the timing of elective caesarean section (ECS) during parturition affects pulmonary and metabolic adaptation to extra-uterine life in healthy Belgian White and Blue (BWB) calves delivered at term. Vaginal palpation was performed and deliveries divided into six categories of timing for ECS: cervix closed (TECS 1); passive and active cervical dilatation (TECS 2 and TECS 3); full cervical dilatation (TECS 4); spontaneous rupture of allantoic (TECS 5) and amniotic (TECS 6) membranes. One hundred and eighteen BWB calves were examined at birth, 5, 15, 30, 45 and 60 min and 2, 3, 6, 12 and 24 h after birth using the following measurements: physical examination (time between birth and sternal recumbency [T-SR]); heart rate (mHR); arterial blood gas analyses (arterial partial pressure in oxygen [PaO(2)], in carbon dioxide [PaCO(2)], arterial haemoglobin oxygen saturation [SaO(2)], alveolo-arterial difference in oxygen [AaDO(2)]); pulmonary function tests using the oesophageal balloon catheter technique (respiratory rate [RR], total pulmonary resistance [R(L)], dynamic lung compliance [C(Ldyn)], tidal volume [V(T)] and minute volume [V(E)]); arterial and venous blood acid-base balance analyses (arterial and venous pH [pHa and pHv], bicarbonate concentration [HCO(3)a and HCO(3)v], base excess [BEa and BEv]); rectal temperature (RT); jugular venous blood sampling for determination of metabolic variables (blood glucose [G], plasma lactate [L], serum cortisol [C], plasma noradrenaline [NA] and adrenaline [A] concentrations); haematological variables (red blood cell count [RBC], total haemoglobin concentration [Hb], Packed Cell Volume [PCV]) and passive immune transfer variables (total serum protein [TP] and beta(2)gammaglobulin [beta(2)gamma] concentrations).TECS significantly (P</=0.05) influenced PaO(2), SaO(2), AaDO(2), RR, V(T), V(E), C(Ldyn), RT, G, NA, A, RBC, Hb and TP: compared to TECS> or =4 calves, TECS< or =3 calves showed lower PaO(2), SaO(2), V(T), C(Ldyn), RT, G, NA, A, RBC, Hb and TP and higher AaDO(2), RR, V(E). TECS differences progressively decreased and disappeared between 6 and 12 h after birth in TECS 2 and 3 calves but remained up to 24 h in TECS 1 calves. Improved postnatal respiratory and metabolic adaptation in TECS> or =4 calves were mainly related to differences in exposure to labour and subsequent hormonal surge: catecholamines, particularly A, enabled more effective removal of lung liquid and/or release of surfactant which contribute to better gas exchanges and induced greater energy mobilization to maintain adequate body temperature. It was concluded waiting for full cervical dilatation before performing CS should be encouraged because it promotes postnatal respiratory and metabolic adaptation in full-term BWB calves.

Influence of prenatal adrenaline infusion on arterial blood gases after caesarean delivery in the lamb

The efficacy of pulmonary gas exchange immediately after delivery is inversely related to the volume of liquid in the lung at birth, but aspiration of as much liquid as possible from the lung before Caesarean delivery fails to improve postnatal oxygenation (Pa,O2) to the level achieved after spontaneous term delivery. We hypothesised that the differing respiratory benefit of aspiration and vaginal delivery results from the differing volume of lung liquid remaining after aspiration (17 ml (kg body weight)-1) and labour (7 ml kg-1). We addressed this hypothesis by reducing lung liquid volume to an estimated 7 ml kg-1 by infusing adrenaline to seven fetal lambs at 140 days gestation (term is 147 days) before performing Caesarean delivery and obtaining postnatal blood gases for comparison with samples from lambs delivered vaginally. Infusion of adrenaline to fetuses caused a progressive decline in arterial O2 saturation (Sa, O2), pH and base excess, but no change in arterial partial pressure of O2 (Pa,O2) or CO2 (Pa,CO2). After birth, Pa,O2 rapidly rose to the same level in adrenaline-treated and vaginal-delivery groups. A severe acidosis occurred in the adrenaline-treated group and this appeared to be related to a higher Pa,CO2 and a transiently lower Sa, O2 in this group. We conclude that adrenaline infusion can enhance postnatal Pa,O2 levels in the newborn lamb, but this beneficial effect may be outweighed by the severe acidosis that develops after prolonged prenatal adrenaline treatment.