Objective: We aimed to assess the association between intrapartum neuraxial labour analgesia (NLA) and shock index values during the peripartum period. Design: A multicentre prospective cohort study. Setting: Two reference centres in Colombia. Population: Obstetric patients in labour with term gestations were divided according to whether they underwent NLA between 2017 and July 2018. Methods: We collected maternal blood pressure and heart rate within the first and second stages of labour and every 30 minutes up to two hours postpartum. We assessed the association between intrapartum NLA and shock index values in a multivariable longitudinal mixed-effect model, adjusting for covariates. Main outcome measures: Shock index changes over time during labour and postpartum periods. Results: We included 522 patients, 228 (43.7%) with NLA and 294 (56.3%) without NLA. Except in the first stage of labour [0.68 (IQR, 0.63-0.74) vs 0.73 (IQR, 0.64-0.82); p=0.07], the shock index values were significantly higher in patients with NLA during the second stage of labour and postpartum (all p values <0.001). In the longitudinal mixed-effect model analysis, shock index values were higher in the NLA group. After adjusting the multilevel model by age, nulliparity, and cervical dilation, the mean shock index without NLA across the measurements was 0.69, while in NLA was 0.76 (mean difference of 0.067). Conclusions: In patients receiving NLA, the shock index values during labour differ from those during the postpartum period. Thus, under these conditions, the shock index should be interpreted differently. Keywords: Shock Index; Neuraxial Labour Analgesia; Postpartum Haemorrhage.

Objective: To evaluate the performance of INTERGROWTH-21st and World Health Organization (WHO) fetal growth charts to identify small-for-gestational-age (SGA) and fetal growth restriction (FGR) neonates as well as their specific risks for adverse neonatal outcomes. Design: Multicenter cross-sectional study. Setting: Ten maternity units across four Latin American countries, 2016-2018. Population: 67,968 singleton live births. Methods: According to each standard, the neonates were classified as SGA and FGR (birthweight <10th and <3rd centiles, respectively). Main Outcomes Measures: The relative risk (RR) and diagnostic performance for the occurrence of a low Apgar score and low ponderal index were calculated for each standard. Results: The WHO charts identified more neonates as SGA than IG-21st (13.9% vs. 7%, respectively). 6.9% babies were considered SGA only by the WHO chart. Compared to normally grown babies, neonates classified as FGRs by both standards had the highest RR for a low Apgar (RR: 5.57; 95% CI: 3.99–7.78), followed by those SGA by both curves (RR: 3.27; 95% CI: 2.52–4.24), while SGAs identified by WHO alone did not have an additional risk (RR: 0.87; 95% CI: 0.55–1.39). Furthermore, the diagnostic odds ratio for a low Apgar was higher when INTERGROWTH-21st was used than when SGA and FGR were defined by WHO charts. Conclusions: In a large population of singleton deliveries from Latin America, the WHO fetal growth charts seem to identify significantly more SGA neonates than the INTERGROWTH-21st charts, but the diagnostic performance of the latter for low Apgar score and low ponderal index is better.