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Second stage of labour in primiparas more
common than previously thought, and
reduces spontaneous vaginal deliveries
Prolonged second stage of labour in primiparas has been shown to be more common than
previously thought. The chance of spontaneous vaginal delivery decreases linearly with the
duration of second stage, report results of a retrospective cohort study.
S
ophia Brismar-Wendel, PhD, of the
Karolinska Institute, Stockholm,
Sweden, explained that prolonged
second stage (>3 h/2 h with/without
epidural analgesia) may increase the risk
of operative vaginal delivery, emergency
caesarean section and obstetric anal
sphincter injury.
The prevalence and effects of prolonged
second stage has been scarcely reported in
Sweden. Dr Brismar Wendel and colleagues
set out to investigate the prevalence of
prolonged second stage, mode of delivery,
and risk of obstetric anal sphincter injury in
primiparous women.
Dr Brismar-Wendel and coinvestigators used
data from computerised hospital records
at a large Swedish university hospital to
review the cases of primiparas who gave
birth in 2013. They included 2668 women
with planned vaginal delivery, singleton
cephalic birth at ≥34 weeks of gestation.
Of these, a fully dilated cervix was noted in
the partograph of 2134. Risk of emergency
caesarean section and operative vaginal
delivery were calculated for women with
a prolonged second stage vs those with
women with a normal second stage.
Risk of obstetric anal sphincter injury was
calculated in women who underwent
operative vaginal delivery after a prolonged
second stage (n=200) and a normal
second stage (n=101), and in women
with spontaneous vaginal delivery with a
prolonged second stage (n=500). Women
who gave birth via spontaneous vaginal
delivery and normal second stage were
used as reference (n=1250).
Multivariable logistic regression analyses
with adjusted odds ratios and 95%
con dence intervals were performed to
control for potential confounding factors
such as body mass index, epidural,
gestational week and maternal age.
A total of 762 (28.6%) women experienced
a prolonged second stage. The chance of
spontaneous vaginal delivery decreased
with every hour from 93.6% to 11.1% at >7 h
(adjusted odds ratio 0.19, 95% CI 0.15–0.25).
Compared with women who experienced
a normal second stage, the adjusted odds
ratio for emergency caesarean section in
womenwhose second stagewas prolonged
4.80 (95% CI 2.85–8.08; 8.3% vs 1.5%) and
for operative vaginal delivery was 4.32 (95%
CI 3.31–5.64; 28.7% vs 7.4%).
Compared with women who gave birth
via spontaneous vaginal delivery and a
normal second stage, adjusted odds ratios
for obstetric anal sphincter injury were 1.42
(95% CI 0.95–2.12; 9.4 vs 6.6%) for women
who gave birth via spontaneous vaginal
delivery with a prolonged second stage,
2.05 (95% CI 1.23–3.40; 15.8%) for women
with operative vaginal delivery and a normal
second stage, and 4.96 (95% CI 3.34–7.36;
28.5%) for women who underwent an
operative vaginal delivery with a prolonged
second stage.
Dr Brismar-Wendel concluded that
prolonged second stage of labour in
primiparas was shown to be more common
than previously thought. The chance of
spontaneous vaginal delivery decreased
linearly with the duration of the second
stage of labour.
The risk of sphincter injury was almost ve
times higher in operative vaginal delivery
after a prolonged second stage. This
information can be used in the management
of the second stage and timing of operative
vaginal delivery.
"
The risk of
sphincter injury
was almost ve
times higher in
operative vaginal
delivery after
a prolonged
second stage.
Dr Sophia Brismar-Wendel
LABOUR
PRACTICEUPDATE CONFERENCE SERIES •
RCOG World Congress 2017
8