Prolonged pregnancy may be result of either parent’s influence

RESEARCHERS have demonstrated that both mothers and fathers contribute to recurrence of prolonged pregnancy across generations, in the first study to assess paternal influence. 

Drawing on intergenerational data from 1967 to 2006 in the Norwegian medical birth registry, researchers examined 478,627 mother-child pairs, 353,164 father-child pairs and 295,455 combined mother-father-child trios to measure the gestational age of the second generation.

A post-term mother had a 49% increased risk of giving birth to a child at ≥ 42 weeks, and a post-term father had a 23% increased risk of fathering a child at ≥ 42 weeks. 

The relative risk of a pregnancy at ≥42 weeks was 76% higher if both parents had been born post-term. 

Brit J Obstet Gynaec 2011; online 10 Oct