INTRODUCTION
Postpartum haemorrhage (PPH) is the leading cause of maternal mortality,
with an estimated 34,000 deaths occurring worldwide in
2017.1 There are profound disparities in maternal
deaths due to PPH, with nearly 90% of all cases occurring in low
middle-income countries.1 The conventional definition
of PPH is a blood loss of ≥500 ml after a vaginal delivery or ≥1,000 ml
in a caesarean section.2 Despite this, current blood
loss estimation methods are inaccurate, leading to underestimating PPH
incidence.3 Because of this, recent initiatives have
suggested that the combination of hemodynamic variables with blood loss
estimation might improve the early identification and definition of
PPH.4
The current literature proposes new indices, such as the shock index (SI
= the ratio of heart rate (HR) to systolic blood pressure (SBP)], as a
valuable clinical sign of haemodynamic instability in the general
population. This parameter also shows a strong ability to predict
adverse outcomes in trauma,5 sepsis6and hypovolemic shock.7 Moreover, cumulative evidence
emphasises its value as a prognostic factor in PPH cases, anticipating
the need for massive transfusion, admission to an intensive care unit
(ICU), and development of severe morbidity.8,9 In the
general population, SI values range from 0.5 to 0.7.7In pregnant women, this value varies from 0.7 to 0.9, and a cut-off
value ≥ 0.9 is considered a threshold for urgent
care.13–16. However, these studies did not consider
confounding factors such as pain, obstetric analgesia, or maternal
anxiety that might induce haemodynamic changes, leading to changes in SI
values.13–15
The use of neuraxial labour analgesia (NLA) is becoming popular in high-
and middle-income countries21,22, owing to its high
reliability, superior pain relief, high patient satisfaction, and low
incidence of complications.16,18 The use of NLA has
been shown to result in changes in blood pressure and
HR.19,20 We hypothesised that SI values in patients
under NLA during labour and the postpartum period would be different
from the SI values of those who did not receive
NLA.13,20–22 Thus, we aimed to compare the changes in
SI values during the active phase of labour up to the first two hours
postpartum in patients with or without intrapartum NLA.