Abstract:
Objective: This study aims to estimate the familial risk of
placental abruption using a large population database.
Design: Retrospective familial aggregation study of placental
abruption utilizing a case-control design.
Population: The Utah Population Database is a genealogic
database of over 11 million individuals, which contains medical and
demographic information linked to official records dating back to the
1900s.
Methods: Cases of placental abruption and controls were
ascertained from birth certificates, death certificates, and inpatient
medical records. Controls were matched 3:1 to cases based on age,
parity, and number of relatives in the database. Familial risk of
placental abruption was estimated using generalized linear mixed-effect
regression and conditional logistic regression.
Main outcome measures: Unadjusted and adjusted odds of
placental abruption between first-, second-, and third-degree relatives.
Results: Of 1,168,378 pregnancies analyzed in the Utah
Population Database, 32,823 cases (2.8%) of placental abruption were
identified. First-degree relatives inherit an adjusted odds of placental
abruption estimated at 1.18 (95% CI: 1.12 – 1.23) when a family member
has had at least one placental abruption, and 1.38 (95% CI: 1.17 –
1.63) with two or more placental abruptions. The estimated effect is
lower for second- and third-degree relatives. After controlling for
clinical risk factors, individuals inherit an adjusted odds of placental
abruption estimated at 1.16 (95% CI: 1.03 – 1.31, p =0.014) with
a first-degree family history of placental abruption. The estimates for
second- and third-degree relatives using this method are not
statistically significant.
Conclusion: These findings represent an argument for the
inheritance of genetic factors which predispose the occurrence of
placental abruption.
Funding: none
Key words: Placental abruption, familial risk analysis,
heritability, adverse pregnancy outcomes