MATERNAL SMOKING AND BLOOD-PRESSURE IN 7.5-YEAR-OLD TO 8-YEAR-OLD OFFSPRING

Reduced fetal growth in babies born preterm may be associated with red uced later blood pressure, but in children born at term, higher blood pressure. It was hypothesised, therefore, that maternal smoking in pre gnancy, associated with reduced fetal growth, programmes later blood p ressure differentially according to length of gestation. Six hundred a nd eighteen children born preterm and now aged 7.5 to 8 years were stu died prospectively. Systolic blood pressure in children from smoking c ompared with non-smoking mothers was significantly lower in those born before 33 weeks' gestation and significantly higher in those born at 33 or more weeks. Within the range 0-40 cigarettes per day until deliv ery (after adjusting for potentially confounding factors, including so cial class and current weight) each 10 was associated with a 1.5 mm Hg fall and 2.9 mm Hg rise in pressure for children born below or above 33 weeks' gestation respectively. Similar though smaller differences w ere seen in diastolic pressure. These data support our hypothesis that later effects of insults impairing fetal growth are gestation depende nt, and provide the first evidence that maternal smoking may have long term consequences for blood pressure in children.