ArticlesCaesarean section and risk of unexplained stillbirth in subsequent pregnancy
Introduction
Rates of caesarean section have risen substantially in recent years.1 The causal factors are complex and incompletely understood.2, 3 Concerns have been expressed about potential adverse effects, especially in relation to short-term morbidity in the mother and child.4, 5 Studies on the effects of previous caesarean section on future pregnancies have focused mainly on the maternal and fetal risks of scar rupture associated with vaginal birth.6, 7 However, it has also been noted that placental complications, such as abruption and placenta praevia, are more common in women who have previously undergone caesarean section,8, 9 and the association with abruption has been observed in women with no previous history of abruption and is independent of obvious confounders.10 The effect of previous caesarean delivery on the risk of antepartum perinatal death in subsequent pregnancies is not known. We did a large-scale, retrospective, cohort study to establish whether caesarean delivery in a first pregnancy was associated with an increased risk of antepartum stillbirth in the second.
Section snippets
Data sources
The Scottish Morbidity Record (SMR2) collects information on clinical and demographic characteristics and outcomes for all patients discharged from Scottish maternity hospitals. The register is subjected to regular quality assurance checks and has been more than 99% complete since the late 1970s.11 A quality assurance exercise was done in 1996–97 in which 5% of case records (n=1414) were compared with the SMR2 database during a 6-month period. All fields used in the present study had fewer than
Results
There were 411 685 singleton births in Scotland between 1992 and 1998, excluding deaths due to fetal abnormality or rhesus isoimmunisation; 144 202 (35%) were second births. Of these, 408 (0·3%) did not have information for gestational age or birthweight, or these values were outside 24–43 weeks or less than 500 g, respectively. Of the remaining 143 794 records, data were missing for previous caesarean delivery in 14 (<0·1%), height in 12866 (9·0%), deprivation category in 448 (0·3%), smoking
Discussion
Our results show that women whose first birth was by caesarean section were at significantly increased risk of having an antepartum stillbirth in their second pregnancy, mainly because of increased risk of unexplained stillbirth. The association with unexplained stillbirth was not attenuated by adjustment for maternal age, height, smoking status, social deprivation, and interpregnancy interval, or for key outcomes of the first pregnancy: birthweight percentile, preterm delivery, and perinatal
References (35)
- et al.
The cesarean birth epidemic: trends, causes, and solutions
Am J Obstet Gynecol
(1996) - et al.
First-birth cesarean and placental abruption or previa at second birth
Obstet Gynecol
(2001) - et al.
Long-term effects of cesarean sections: ectopic pregnancies and placental problems
Am J Obstet Gynecol
(1996) - et al.
Risk of unexplained stillbirth at different gestational ages
Lancet
(1987) Life-table analysis of the risk of perinatal death at term and post term in singleton pregnancies
Am J Obstet Gynecol
(2001)- et al.
Survival plots of time-to-event outcomes in clinical trials: good practice and pitfalls
Lancet
(2002) - et al.
Planned caesarean section versus planned vaginal birth for breech presentation at term: a randomised multicentre trial. Term Breech Trial Collaborative Group
Lancet
(2000) - et al.
The contribution of dystocia to the cesarean section rate
Am J Obstet Gynecol
(1994) - et al.
Individualized risk assessment for adverse pregnancy outcome by uterine artery Doppler at 23 weeks
Obstet Gynecol
(2001) - et al.
Doppler ultrasonography in high-risk pregnancies: systematic review with meta-analysis
Am J Obstet Gynecol
(1995)
Predictors of Cesarean delivery
Curr Probl Obstet Gynecol Fertil
Effects of changes in maternal age, parity and birth weight distribution on primary Cesarean section rates
JAMA
Infections following cesarean section
Curr Opin Obstet Gynecol
Neonatal respiratory morbidity and mode of delivery at term: influence of timing of elective caesarean section
Br J Obstet Gynaecol
Risk of uterine rupture during labor among women with a prior cesarean delivery
N Engl J Med
Risk of perinatal death associated with delivery after previous caesarean section
JAMA
A history of placental dysfunction and risk of placental abruption
Paediatr Perinat Epidemiol
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