Late Age at First Birth is a Protective Factor for Preterm Labor and Delivery: The Evidence From the Genetic Study

Area of Science:

• Reproductive genetics
• Perinatal epidemiology

Background:

• The relationship between age at first birth (AFB) and preterm labor and delivery is complex.
• Understanding the genetic underpinnings can elucidate causal pathways.

Purpose of the Study:

• To investigate the genetic link between age at first birth (AFB) and the incidence of preterm labor and delivery.
• To assess whether AFB is a risk or protective factor for preterm birth using genetic data.

Main Methods:

• Utilized Mendelian randomization (MR) with genomewide association analysis (GWAS) summary data.
• Employed inverse-variance weighted (IVW), MR Egger, and weighted median methods.
• Assessed heterogeneity and horizontal pleiotropy using Cochrane's Q and MR-PRESSO tests; conducted leave-one-out analysis for sensitivity.

Main Results:

• Mendelian randomization analysis, particularly the IVW method, indicated that age at first birth (AFB) is a significant protective factor against preterm labor and delivery (p < .001).
• Statistical tests for heterogeneity and horizontal pleiotropy suggested the findings were robust and unlikely to be biased (p > .05).
• Leave-one-out analysis confirmed the stability of the observed association.

Conclusions:

• Age at first birth (AFB) demonstrates a protective effect on preterm labor and delivery.
• The genetic evidence supports a causal relationship, though further research is needed to explore the biological mechanisms involved.