The phrase "average birth interval" is correct and usable in written English.
It can be used in discussions related to demographics, reproductive health, or population studies to refer to the average time between consecutive births in a population.
Example: "The study found that the average birth interval in the region has increased over the past decade."
Alternatives: "mean birth spacing" or "typical birth interval".
This resulted in reduced family size and increases in average birth intervals and may in part be explained by the increase in contraceptive use – from 7percentnt in 1975 to 54 per cent by 2000 in Bangladesh [ 9].
However, it is difficult in our analysis to disentangle the effects of age, parity and age at first pregnancy, which will all correlate with average past birth intervals and are associated with the interval of interest.
After controlling for place of residence, household wealth quintile and sex of child, child's age group, perceived small or average birth size, and birth interval of 48 months or longer since previous birth were significantly associated with stunting.
Because these zeros would render regression analyses ineffective, we transformed the annual estimates of Mx, Rec, and SR into 3-year running averages (the normal birth interval) to eliminate most of the zeros.
We examined more specific life-history traits involved in LRS: age at first reproduction, age at last reproduction, and average inter-birth interval (i.e. length of reproductive life divided by the number of children).
Women in the study area have been practicing on average 7 months shorter birth interval length than they would prefer otherwise and the preferred length of birth interval among the study subjects is significantly greater than actual birth interval length.
In the demographic and health survey analytical study conducted in 20 sub-Saharan countries, the median length of actual birth intervals was 33.7 months on average compared with preferred birth interval of almost 39.9 months [ 17].
IPI was calculated by subtracting the average gestation period from the birth interval.
