Impact of the mode of delivery on the short-term outcome of preterm deliveries ≤34+0 weeks of gestation – a retrospective study on 1597 neonates

Introduction:

Preterm birth is called delivery less than 37 weeks of gestational age and is known as the leading cause of perinatal morbidity and mortality in industrial nations. The optimal route of delivery for preterm neonates remains controversial and yet it's not finally clear, if an influence of the mode of delivery on neonatal outcome exists at all. As data on preterm birth management is limited, the aim of this study is to analyse a potential influence of the mode of delivery on neonatal short-term outcome in preterm infants.

Methods:

In this population-based study all women with a preterm delivery between 23+0 and 34+0 weeks of gestation, who gave birth between 01/2004 and 12/2012 in one of the ten public hospitals in the region of Styria were identified. Preterm infants were grouped according to gestational age in four groups with 23+0 – 27+0, 27+1 – 29+0, 29+1 – 31+0 and 31+1 – 34+0 weeks of gestation. Outcome parameters were arterial blood cord pH, apgar 5' and 10' score which served as measurement for fetal short-term outcome. Fetal weight to differ between SGA/IUGR and AGA was also collected. Although not the same, our data record system does not provide the possibility to discriminate between fetuses, which are just SGA and fetuses which are IUGR.

Results:

In total n = 1597 women were included. The most common mode of delivery was caesarean section (35.7% elective cs and 32.4% secondary cs), 30.3% delivered spontaneously, vaginal breech delivery (0.3%) and instrumented vaginal delivery (1.3%) also were included but rare. A significant influence of the mode of delivery on arterial cord blood pH levels could be seen only between 29+1 – 31+0 (p = 0.026) and 31+1 – 34+0 (p =< 0.001) weeks of gestation in favour of spontaneous delivery. In SGA fetuses caesarean section was performed significantly more often than vaginal delivery (121/127 vs. 6/127, p < 0.001, respectively). Compared to AGA fetuses, arterial cord blood pH was lower in SGA fetuses after secondary caesarean section (pH = 7.22 vs. pH = 7.26, p = 0.018), but no differences in APGAR scores was detected. No differences were identified for spontaneous deliveries and elective caesarean sections.

Conclusio:

Our study showed no benefit for caesarean section in all subgroups for AGA. Significantly lower umbilical artery pH after secondary caesarean section may implicate reduced capability of managing fetal distress during vaginal birth. But subdivision between SGA and IUGR should be performed to give a clear statement for optimal mode of delivery.

No conflict of interest has been declared by the author(s).