Work

Delayed umbilical cord clamping and early maternal haematological outcomes: a calendar-time-adjusted cohort of 4,632 deliveries

Year: 2026

Type: preprint

Abstract: Background. Delayed umbilical cord clamping (DCC) is recommended for neonatal benefit, but maternal haematological safety concerns persist and may slow uptake. Because DCC is adopted progressively, calendar time confounds implementation-era cohorts. We estimated the association between DCC ≥ 60 seconds and early postpartum maternal haematological outcomes with explicit adjustment for calendar-time confounding. Methods. Single-centre retrospective cohort of 4,644 consecutive deliveries at ≥ 22 weeks’ gestation between 6 June 2022 and 31 December 2024 (4,632 with valid delivery dates for the calendar-adjusted analysis) at a university obstetric department in Ankara, Turkey. The exposure was DCC ≥ 60 seconds versus immediate or 30-second clamping. Calendar time was modelled as a natural cubic spline. The primary analysis used stabilised inverse-probability-of-treatment weighting (IPTW); covariate-adjusted modified Poisson regression, overlap weighting and 1:1 propensity-score matching were complementary analyses. Firth-penalised logistic regression handled the sparse transfusion outcome, and E-values addressed unmeasured confounding. The primary outcome was postpartum anaemia (venous haemoglobin < 10 g/dL at 6 hours). Results. 1,889 (40.8%) episodes received DCC; adoption rose from 10.2% in 2022 to 62.3% in 2024. On the primary analysis, DCC was not associated with postpartum anaemia (stabilised IPTW risk ratio 1.01, 95% CI 0.88–1.16; covariate-adjusted 1.00, 0.91–1.10; overlap 0.99, 0.87–1.13), postpartum haemorrhage (1.11, 0.77–1.59), haemoglobin drop ≥ 2 g/dL (0.98, 0.81–1.18) or blood transfusion (0.74, 0.24–2.25). A propensity-score-matched sensitivity analysis that did not achieve calendar-time balance (maximum standardised mean difference 0.18, versus 0.05 under IPTW) gave concordant, non-significant estimates (anaemia 0.93, 0.82–1.07). An exploratory delivery-mode interaction was observed (interaction ratio 0.78, 95% CI 0.65–0.93; p = 0.007): vaginal delivery 1.19 (1.02–1.38); caesarean delivery 0.91 (0.81–1.03). Conclusions. After calendar-time-adjusted multimethod analysis, DCC ≥ 60 seconds was not associated with worse maternal haematological outcomes overall. The delivery-mode divergence is hypothesis-generating and warrants prospective evaluation before any change in practice. Trial registration. Not applicable (observational cohort study).

Source: Research Square

DOI: 10.21203/rs.3.rs-10450694/v1