Risk factors and recurrence of cause-specific postpartum hemorrhage: A population-based study

Abstract

Objective To explore risk profiles of the different types of postpartum hemorrhage (PPH >500ml or severe PPH >1500ml) and their recurrence risks in a subsequent delivery. Methods With data from The Medical Birth Registry of Norway and Statistics Norway we performed a population-based cohort study including all singleton deliveries in Norway from 1967–2017. Multilevel logistic regression was used to calculate odds ratio (OR), with 95% confidence interval (CI), with different PPH types (PPH >500ml or PPH >1500ml (severe PPH) combined with retained placenta, uterine atony, obstetric trauma, dystocia, or undefined cause) as outcomes. Result We identified 277 746 PPH cases of a total of 3 003 025 births (9.3%) from 1967 to 2017. Retained placenta (and/or membranes) was most often registered as severe PPH (29.3%). Maternal, fetal, and obstetric characteristics showed different associations with the PPH types. Male sex of the neonate was associated with reduced risk of PPH. This effect was strongest on PPH due to retained placenta (adjusted OR, (aOR): 0.80, 95% CI 0.78–0.82), atony (aOR 0.92, 95% CI: 0.90–0.93) and PPH with undefined cause (aOR 0.96, 95% CI: 0.95–0.97). Previous cesarean section showed a strong association with PPH due to dystocia (aOR of 13.2, 95% CI: 12.5–13.9). Recurrence risks were highest for the same type: PPH associated with dystocia (aOR: 6.8, 95% CI: 6.3–7.4), retained placenta and/or membranes (aOR: 5.9, 95% CI: 5.5–6.4), atony (aOR: 4.0, 95% CI: 3.8–4.2), obstetric trauma (aOR: 3.9, 95% CI: 3.5–4.3) and PPH of undefined cause (aOR: 2.2, 95% CI: 2.1–2.3). Conclusion Maternal, fetal and obstetric characteristics had differential effects on types of PPH. Recurrence differed considerably between PPH types. Retained placenta was most frequently registered with severe PPH, and showed strongest effect of sex; delivery of a boy was associated with lower risk of PPH. Previous cesarean increased the risk of PPH due to dystocia.

Risk of recurrent red‐cell transfusion in delivery: A nationwide longitudinal study

“…This is in line with the findings of Oberg et al, who found an overall increased risk of the recurrence of postpartum haemorrhage across all haemorrhage subtypes 9 . However, it is in contrast with the findings of Linde et al, who found significant differences in the recurrence risk for postpartum haemorrhage, where the strongest risk for recurrence was found for dystocia, retained placenta and atony 8 . It should be stated that many of these diagnoses are interconnected, and that medical coding may not fully reflect the complexity of a postpartum haemorrhage.…”

“…Haemorrhage after delivery remains one of the leading causes of postpartum maternal morbidity and mortality worldwide, 5 and blood loss after delivery is also a common indication for maternal red‐cell transfusion. Studies show an increased risk of recurrent blood loss in delivery in women with previous postpartum haemorrhage 6–9 . Although the mechanisms driving recurrent haemorrhage can be difficult to disentangle, it may be explained by the persistence of both endogenous and environmental predisposing factors 10,11 …”

“…Studies show an increased risk of recurrent blood loss in delivery in women with previous postpartum haemorrhage. [6][7][8][9] Although the mechanisms driving recurrent haemorrhage can be difficult to disentangle, it may be explained by the persistence of both endogenous and environmental predisposing factors. 10,11 Previous studies have investigated risk factors for red-cell transfusion in delivery, 3,12,13 and have found that they are similar to those associated with postpartum haemorrhage.…”

Development of Clinical Risk-prediction Models for Uterine Atony Following Vaginal and Cesarean Delivery

“…An antepartum model, which included demographic, pregnancy-related, and maternal comorbidities; and an intrapartum model, which included labor and delivery-related risk factors. The event rate of uterine atony was determined to be 16%, a figure consistent with other reports from the literature 4. As stated above, <1% of patient records contained a diagnostic code indicating a prior PPH.…”

“…The event rate of uterine atony was determined to be 16%, a figure consistent with other reports from the literature. 4 As stated above, <1% of patient records contained a diagnostic code indicating a prior PPH. Multiple gestations was identified as a risk factor with an odds ratio (OR) > 2 in both models, while there was a negative association (OR <0.51) with a perineal laceration in the intrapartum model.…”