Short- and Long-term Outcomes after Cesarean Section

Rosalie M Grivell; Jodie M Dodd

Disclosures

Expert Rev of Obstet Gynecol. 2011;6(2):205-215. 

In This Article

Infant & Childhood Health

The effect of CS on perinatal mortality remains unclear, although a reduction in risk is frequently cited as a potential benefit of cesarean birth.[25] An Icelandic study of birthweight-specific mortality rates did not identify a correlation between mode of birth and perinatal mortality for singleton infants with birth weight above 2500 g, in the absence of congenital anomalies.[74] In contrast, Villar reported elective cesarean to be associated with a significant reduction in the risk of fetal death compared with vaginal birth (adjusted OR: 0.65; 95% CI: 0.43–0.98 [adjusted for gestational age and maternal and demographic characteristics]).[30] For breech and other fetal presentations, elective or intrapartum cesarean birth was similarly associated with a large reduction in fetal death after adjusting for gestational age and maternal factors.[30] However, this association was not observed for intrapartum cesarean birth.[30]

In developed countries with low perinatal mortality, studies with a sample size of hundreds of thousands of women would be required to conclusively demonstrate a benefit in infant health outcomes associated with cesarean birth compared with vaginal birth. Consequently, many studies have focused on more common surrogate adverse infant outcomes, including composite measures of perinatal morbidity.

There is a well-recognized risk of respiratory morbidity following elective CS, even at term. Morrison et al. reported the RR of respiratory distress syndrome (RDS) and transient tachypnoea of the newborn (TTN) in over 33,000 births at term comparing mode of birth and gestational age at birth.[75] Although the incidence of RDS and TTN was low, at 2.2 out of 1000 births, and 5.7 out of 1000 births respectively, the incidence of any respiratory morbidity was highest for infants delivered by CS before the onset of labor (35.3 out of 1000) compared with vaginal birth (5.4 out of 1000; OR: 6.8; 95% CI: 5.2–8.9).[75]

Hansen et al. conducted a systematic review to assess the relationship between birth by elective CS and infant respiratory morbidity.[76] A total of nine studies were included (one case–control, one prospective cohort and seven retrospective cohort studies) but results were not able to be combined in a meta-analysis owing to differences in methodology.[76] Overall, there was a two- to three-times greater risk of all types of respiratory morbidity (RDS, TTN, persistent pulmonary hypertension, mechanical ventilation, pneumonia and meconium aspiration) reported following cesarean birth at term.[76] Similarly, the large WHO study involving almost 100,000 births confirmed that both elective and intrapartum cesarean birth was associated with a doubling of the risk of admission (for any indication) to a neonatal ICU for 7 or more days (adjustment for confounding variables and gestational age).[30]

The risk of respiratory morbidity and subsequent admission to neonatal ICU is modified by gestational age at term. In Hansen's systematic review, the magnitude of this risk decreased with advancing gestational age, although a small risk remained with birth after 39 completed weeks of gestation.[76] In a prospective cohort study by Hansen et al., data were collected on the incidence of respiratory morbidity (RDS, TTN, persistant pulmonary hypertensive newborn) and serious respiratory morbidity (oxygen therapy for more than 2 days, nasal continuous positive airway pressure or mechanical ventilation).[35] Infants born vaginally formed the standard reference comparison. Infants delivered by CS had a significantly increased risk of respiratory morbidity at 37 weeks (OR: 3.9; 95% CI: 2.4–6.5), 38 weeks (OR: 3.0; 95% CI: 2.1–4.3) and 39 weeks (OR: 1.9; 95% CI: 1.2–3.0).[35] By contrast, other authors have reported a minimally increased risk with CS birth at 39 weeks when compared with vaginal birth.[77]

The documentation of a gestational age-dependent risk of respiratory morbidity with term elective CS birth has resulted in clinical guidelines advocating elective CS be performed where possible after 39 weeks,[42] and consideration of antenatal corticosteroids. The Antenatal Steroids for Term Elective Caesarean Section (ASTECS) randomized trial evaluated the effect of antenatal betamethasone administration for women with a planned elective CS at a gestational age of 37 weeks or more.[78] The incidence of admission to the special-care baby unit with RDS was 5.1% in the control group, compared with 2.4% (RR: 0.46; 95% CI: 0.23–0.93) following betamethasone administration.[78] While the incidence of RDS was reduced following antenatal corticosteroids (1.1 vs 0.2%; RR: 0.21; 95% CI: 0.03–1.32), there were no other significant differences identified in other measures of neonatal morbidity.[78]

With regards to longer term infant health outcomes following CS, the Term Breech randomized trial reported outcomes at 3 months and 2 years after planned CS compared with planned vaginal birth for breech presentation at term.[52,79] There were no significant differences identified in infant health, including need for additional medical care after birth, and neurodevelopment as assessed by the Ages and Stages Questionnaire.[52,79]

There have been recent concerns regarding the effect of cesarean birth on later childhood health, particularly in relation to allergy, atopy and autoimmune disease. Although there is evidence of altered immune components in cord blood with mode of birth,[80] the subsequent risk of atopy, asthma and allergy remains uncertain.[81–83]

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