birth interval among nomad women

to have an, idea about the relation between the length of birth interval and lactation, and birth control program this study have been done. the material for such analysis was nomad women's fertility history that was in their reproductive period (15-44). the material itself was gathered through a health survey. the main sample was composed of 2,165 qualified women, of whom 49 due to previous or presently using contraceptive methods and 10 for the lack of enough data were excluded from 'this study. purpose of analysis was to find a relation between no. of live births and pregnancies with total duration of married life (in other word, total months which the women were at risk of pregnancy). 2,106 women which their fertility history was analyzed had a totally of272, 502 months married life. during this time 8,520 live births did occurred which gave a birth interval of 32 months. as pregnancy termination could be through either live birth, still birth or abortion (induced or spontaneous), bringing all together will give no. of pregnancies which have occurred during this period (8,520 + 124 + 328 = 8,972) with an average of interpregnancy interval of 30.3 months. considering the length of components of birth interval: post partum amenorrhea which depends upon lactation. - anovulatory cycles (2 month) - ooulatory exposure, in the absence of contraceptive methods (5 months) - pregnancy (9 months).difference between the length, of birth interval from the sum of the mentioned period (except the first component), (2 + 5+ 9 = 16) will be duration of post partum amenorrhea (32 - 16 = 16), or in other word duration of breast feeding among nomad women. in this study it was found that, in order to reduce birth by 50% a contraceptive method with 87% effectiveness is needed.