Consanguinity: a risk factor for preterm birth at less than 33 weeks' gestation.

Area of Science:

• Genetics
• Reproductive Health
• Pediatrics

Background:

• Consanguinity increases homozygosity for recessive genes, aiding study of recessive disease components.
• Preterm birth (PTB) has uncertain inheritance patterns, making consanguinity a relevant factor to investigate.

Purpose of the Study:

• To assess the association between consanguinity and preterm birth (PTB).
• To stratify PTB risk by gestational age (early PTB <33 weeks, late PTB 33-36 weeks) and clinical presentation (spontaneous vs. medically indicated).

Main Methods:

• Retrospective analysis of 39,745 singleton livebirths without major birth defects in Lebanon (2003-2007).
• Multinomial multiple logistic regression used to compare early PTB and late PTB with births after 36 weeks, considering parental consanguinity (cousin marriage).

Main Results:

• Infants of consanguineous parents had a 1.6-fold increased risk of early PTB (<33 weeks).
• This increased risk was statistically significant only for spontaneous PTB.
• No significant association found between consanguinity and PTB at 33-36 weeks for either presentation.

Conclusions:

• Findings support a genetic contribution to early-onset PTB.
• Early PTB (<33 weeks) should be the focus of future genetic studies, rather than grouping all PTB (<37 weeks).