Results
The number of births at the CHWC in both the pre and post intervention
period is summarised in Table 1. The number of singleton births in the
pre intervention period was 17355 and the number of births in the post
intervention period was 4592. The annual rates of preterm and early term
births including iatrogenic births with no medical indication (NMI) are
shown in Table 2. The trends for preterm and early term births including
iatrogenic births with NMI are shown in Figure 1. The average rates pre
intervention are illustrated with the black horizontal bar and noted in
the attached text box and the initiation of the intervention is
illustrated with a red vertical bar. Table 3 demonstrates the
differences between pre and post intervention with respect to preterm
and early term births.
The rate of PTB (20-36 weeks) within the post intervention period was
8.75% which was significantly lower than the preceding 5 years with an
average of 9.74 % (OR 0.88 95% CI 0.79-0.99 p= 0.05). This resulted in
a 10% reduction in rates of PTB. When the rates of PTB were separated
into grouped gestational ages there was a significant reduction in the
20-23+6 weeks gestation group, 0.82% v 0.52% (OR 0.63 95% CI 0.41 –
0.97 p=0.03), a non-significant reduction for the 24-27+6 week gestation
group, 0.79% v 0.67% (OR 0.84 95% CI 0.57 –1.25 p = 0.40), a
significant reduction for the 28-31+6 weeks gestational group, 1.46% v
0.73% (OR 0.73 95% CI 0.54 – 1.00 p=0.05) and a non-significant
increase for the 32-36 weeks gestational group, 4.47% v 4.5% (OR 1.00
95% CI 0.86 – 1.17 p=0.92).
The rates of early term births (37-38+6 weeks) within the post
intervention period was 25.78% which was a significant increase in
births compared to the preceding five years with an average of 23.95%
(OR 1.10 95% CI 1.02 – 1.18 p=0.009). When further analysed, there was
a significant reduction in iatrogenic early term births with NMI,
18.84% v 12.33% (OR 0.73 95% CI 0.61 – 0.87 p=0.0001) which equated
to a 34% reduction in iatrogenic early term births with NMI.
Table 4 displays the estimated number of PTB and iatrogenic early term
births with NMI averted or delayed post intervention. The estimated
number of averted or delayed PTBs based on the 10% reduction was 45 and
the estimated number of iatrogenic
early term births with no medical indication that were averted or
delayed based on the 34% reduction was 77.