Revisiting the association between maternal and offspring preterm birth using a sibling design

Area of Science:

• Obstetrics and Gynecology
• Perinatology
• Reproductive Epidemiology

Background:

• Previous studies suggest an intergenerational link between maternal and offspring preterm birth (PTB), but the precise nature of this association requires further clarification.
• Understanding this link is crucial for identifying at-risk pregnancies and improving perinatal outcomes.

Purpose of the Study:

• To investigate the intergenerational association between maternal and offspring preterm birth (PTB).
• To differentiate the association based on the type of preterm birth (spontaneous vs. provider-initiated).

Main Methods:

• A retrospective intergenerational cohort study involving 39,573 women and their 79,198 singleton infants in Manitoba, Canada.
• Utilized a quasi-experimental sibling design and compared differentially exposed cousins to control for familial confounding.
• Defined PTB as delivery before 37 weeks of gestation, categorized into spontaneous and provider-initiated.

Main Results:

• In the general cohort, mothers born preterm had a higher likelihood of delivering preterm infants (Adjusted Relative Risk [ARR]: 1.39; 95% Confidence Interval [CI]: 1.25, 1.54).
• However, the sibling analysis revealed no significant intergenerational association when comparing sisters with discordant PTB status.
• Intergenerational patterns were observed for spontaneous PTB but not for provider-initiated PTB.

Conclusions:

• The risk of offspring PTB appears linked to the mother's history of delivering preterm, rather than her own preterm birth status.
• A female family history of PTB may be a more effective indicator of future preterm delivery risk than maternal PTB status alone.
• Future research should differentiate between types of PTB to better understand intergenerational patterns.