ObjectivesTo determine risk factors for short and long umbilical cord, entanglement and knot. Explore their associated risks of adverse maternal and perinatal outcome, including risk of recurrence in a subsequent pregnancy. To provide population based gestational age and sex and parity specific reference ranges for cord length.DesignPopulation based registry study.SettingMedical Birth Registry of Norway 1999–2013.PopulationAll singleton births (gestational age>22weeks<45 weeks) (n = 856 300).MethodsDescriptive statistics and odds ratios of risk factors for extreme cord length and adverse outcomes based on logistic regression adjusted for confounders.Main outcome measuresShort or long cord (<10th or >90th percentile), cord knot and entanglement, adverse pregnancy outcomes including perinatal and intrauterine death.ResultsIncreasing parity, maternal height and body mass index, and diabetes were associated with increased risk of a long cord. Large placental and birth weight, and fetal male sex were factors for a long cord, which again was associated with a doubled risk of intrauterine and perinatal death, and increased risk of adverse neonatal outcome. Anomalous cord insertion, female sex, and a small placenta were associated with a short cord, which was associated with increased risk of fetal malformations, placental complications, caesarean delivery, non-cephalic presentation, perinatal and intrauterine death. At term, cord knot was associated with a quadrupled risk of perinatal death. The combination of a cord knot and entanglement had a more than additive effect to the association to perinatal death. There was a more than doubled risk of recurrence of a long or short cord, knot and entanglement in a subsequent pregnancy of the same woman.ConclusionCord length is influenced both by maternal and fetal factors, and there is increased risk of recurrence. Extreme cord length, entanglement and cord knot are associated with increased risk of adverse outcomes including perinatal death. We provide population based reference ranges for umbilical cord length.
Introduction Studies on the family aggregation of postpartum hemorrhage (PPH) are scarce and with inconsistent results, and to what extent current birthweight influences recurrence between relatives remains to be studied. Further, family aggregation of PPH has been studied from an individual, but not from a public heath perspective. We aimed to investigate family aggregation of PPH in Norway, how birthweight influences these effects, and to estimate the proportion of PPH cases attributable to a family history of PPH and current birthweight. Material and methods Using data from the Medical Birth Registry of Norway, Statistics Norway, and Central Population Registry of Norway we identified individuals as newborns, parents, grandparents, and full and half‐siblings, and studied 1 002 687 mother–offspring, 841 164 father–offspring, and 761 011 both‐parents–offspring pairs. We used multilevel logistic regression to calculate odds ratios (OR) with 95% CI. Results If the birth of the mother but not of the father involved PPH, then the OR of PPH (>500 mL) in the next generation was 1.44 (95% CI 1.39–1.49). If the birth of the father but not of the mother involved PPH, then OR was 1.12 (95% CI 1.08–1.16). These effects were stronger in severe PPH. Recurrence between siblings was highest between full sisters (OR 1.47, 95% CI 1.41–1.52), followed by maternal half‐sisters, paternal half‐sisters, and partners of full brothers. A family history of PPH or birthweight of 4000 g or more accounted for ≤5% and 15% of the total number of PPH cases, respectively. Conclusions A history of PPH in relatives influenced the recurrence risk of PPH in a dose–response pattern consistent with the anticipated proportion of shared genes. The recurrence was highest through the maternal line.
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.
Purpose This study examines individual aggregation of postpartum hemorrhage (PPH), paternal contribution and how offspring birthweight and sex influence recurrence of PPH. Further, we wanted to estimate the proportion of PPH cases attributable to a history of PPH or current birthweight. Methods We studied all singleton births in Norway from 1967 to 2017 using data from Norwegian medical and administrational registries. Subsequent births in the parents were linked. Multilevel logistic regression was used to calculate odds ratios (ORs) with 95% confidence intervals (CI) for PPH defined as blood loss > 500 ml, blood loss > 1500 ml, or the need for blood transfusion in parous women. Main exposures were previous PPH, high birthweight, and fetal sex. We calculated adjusted population attributable fractions for previous PPH and current high birthweight. Results Mothers with a history of PPH had three- and sixfold higher risks of PPH in their second and third deliveries, respectively (adjusted OR 2.9; 95% CI 2.9–3.0 and 6.0; 5.5–6.6). Severe PPH (> 1500 ml) had the highest risk of recurrence. The paternal contribution to recurrence of PPH in deliveries with two different mothers was weak, but significant. If the neonate was male, the risk of PPH was reduced. A history of PPH or birthweight ≥ 4000 g each accounted for 15% of the total number of PPH cases. Conclusion A history of PPH and current birthweight exerted strong effects at both the individual and population levels. Recurrence risk was highest for severe PPH. Occurrence and recurrence were lower in male fetuses, and the paternal influence was weak.
Women born small for gestational age have excess risk of placental abruption.
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