The objective of the study was to relate blood pressure levels in children to their mother's weight in pregnancy. The blood pressures of 675 children aged from one to nine years in three villages in rural Gambia were measured. They were matched to antenatal clinic data which had been collected from all pregnant women in the three villages since 1980. Among children under eight years of age those born in the dry season had the highest blood pressures and were heavier. Their blood pressures were positively related to body weight and to mothers' weight at six months of pregnancy. These relationships were independent of mothers' age and parity, birthweight, gestational age, and placental weight. Among older children, aged eight and nine years, those born in the rainy season had the highest blood pressures. Their blood pressures were not related to their mothers' weight at six months of pregnancy. Rather they were inversely related to mothers' weight gain in the last trimester. An interpretation of these findings is that among young children differences in blood pressure are largely determined by rates of maturation. However, the long-term effects of adverse intra-uterine influences which elevate blood pressure become apparent in older children.
PIP: Recent findings show that the intrauterine environment has a major effect on blood pressure and hypertension. This article reports on a study of the blood pressure of 675 Gambian children 1-9 years old and the relationship to mother's weight in pregnancy and seasonality. The children were born in the rural Keneba, Manduar, and Kanton Kunda in The Gambia after January 1980. Since 1979, clinic data was available on child's birth weight, growth, and morbidity data within the 1st 18 months, and after 18 months, clinic visit data on weight, height, diagnosis, and treatment. Mother's anthropometry and blood pressure (BP) were used at within 15 days of 6 months and 30 days of birth; mother's BP is not comparable between younger and older children. Periodic census data on households was also accessible. A study survey was also administered in 1989. Children's height was measured with a Harpenden infantometer for those 900 mm, and with a Raven Maximeter for those 900 mm. A SECA medal 727 (5 g gradations) was used for lower weights and a SOEHNLE digital scale for mother's and for heavier children. DINAMAP (model 18465 X) was used for 2 BP readings. A BP pretest with 2 observers revealed a mean difference in readings of .27 and a standard error of 1.36. Seasonality was set at rainy (Aug-Nov), cool (Apr-Jly), and hot and dry (Dec-Mar). The results were that systolic and diastolic pressures rose with children's age; i.e., from 89.3 mm Hg in 1 year olds to 102.7 mm Hg in 9 year olds. It increased with body weight and decreased with the time since the last meal. Ambient temperature was unrelated. Cole's LMS method for calculating centile curves was used to adjust the data for age, body weight, and time since eating. In the age groups 1-4, 5-7, mean BP was lowest during the rainy season and among 8-9 year olds, BP was highest during rainy seasons and variation was statistically significant. Mother's weight gain was lowest in the rainy season and among 8-9 year olds, BP was highest during rainy seasons and variation was statistically significant. Mother's weight gain was lowest in the rainy season and BP increased with age. Every 10mm Hg rise in mother's systolic BP was related to a 1 mm Hg rise in children's (1-7 years) adjusted systolic BP (p=.008). Mother's weight at 7.5 months was positively related to the child's (1-7 years) adjusted systolic BP (p=.003). There was no trend for children 8-9 years. Among the younger children BP was not related to mother's weight gain. Birthweight was unrelated to adjust systolic pressure at any age, but strongly positively related to mother's height, mother's weight at 7.5 months, and weight gain in the last trimester. Future followup is planned to examine whether the 6-7 year olds a year later begin to show the effects of maternal weight gain in pregnancy.