Potential harms and benefits of planned cesarean delivery of fetuses in breech presentation at term. An observational study from Norway
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The optimal mode of delivery of a fetus in breech presentation has been debated for more than half a century and remains a controversial topic in modern obstetrics. Already in the 1950s, observational studies showed increased fetal mortality in vaginal breech delivery compared to planned caesarean delivery (CD). Despite these findings, the risk of maternal complications after CD was high and this had to be weighed against the harm for the offspring. In 2000, a long awaited large randomized controlled trial, including 121 centers in 26 different countries, was published in the Lancet. The Term Breech Trial (TBT) showed an increased risk of morbidity and mortality in children born vaginally in breech compared to those born with CD. The publication had great impact on clinical practice worldwide, and planned CD quickly became the preferred mode of delivery. However, the study was criticized by several experts, and in Norway a group of national experts reviewed the evidence underlying these recommendations. Taking into consideration the much lower perinatal mortality in Norway than that which was reported in the TBT, they concluded that vaginal delivery would still be safe, provided careful assessment of maternal and fetal status. With safer surgical techniques, effective antibiotics and the availability of blood transfusion, planned CD in middle- and high-income countries is considered as safe as a normal vaginal delivery. Despite this, there is rising concern about the consequences a CD may have for the offspring and for subsequent pregnancies. In this thesis I therefore want to increase the knowledge of acute and late complications for children born vaginally in breech or by CD in a population with low perinatal mortality; in the same population, independent of fetal presentation, I examine potential complications of CD for subsequent pregnancies, both for the mother and the offspring. In this thesis, data was retrieved from the Medical Birth Registry of Norway (MBRN) and combined with data from the Cerebral Palsy Registry of Norway (CPRN). In addition, in Paper II, a perinatal audit was performed with thorough reviews of medical records from 1999-2015 of the women who lost their child, either intrapartum or in the neonatal period, born at term in breech and without congenital anomalies recorded in the MBRN. These births were compared with control deliveries – children born at term in breech that survived. In our first study assessing the risk for cerebral palsy in children born in breech at term, the study did not show increased risk for cerebral palsy in children born as singleton in breech compared to children born in cephalic, when congenital anomalies were excluded. However, when we compared singletons born in breech with singletons born in cephalic presentation, we found a small but significantly increased risk of intrapartum or neonatal death. In the perinatal audit, all the in hospital births were in line with Norwegian guidelines for breech delivery. However, antenatal care and/or management of the deliveries was more often assessed suboptimal in the case group than in the controls. In our third study assessing the risk for CD in subsequent pregnancy, independent of fetal presentation, the study found a small associated risk of stillbirth, perinatal mortality and cerebral palsy among infants born after the mother had previously had a CD compared with children born after the mother had previously had a vaginal delivery (VD). Mothers with a previous CD had an increased risk of placental complications and uterine rupture, and their fetuses had an increased risk of being small for gestational age (SGA) and being born prematurely. In Norway, with its very good maternity care and one of the lowest perinatal mortalities in the world, it is important to emphasize that the absolute risk for death intrapartum or in the neonatal period is very low, also when born vaginally in breech. Rising concerns regarding complications in later pregnancies and the future health of children born by planned CD compared with VD must also be weighed against this very low absolute risk of death. Keeping these factors in mind, our studies conclude that vaginal delivery may still be offered to women with a fetus in breech presentation, provided competent obstetric care and strict criteria for selection of vaginal delivery.