YearMultiparous MothersInterpregnancy Interval
Short IPIIPI of 12-35 MonthsIPI of 36 Months and over
NumberRateNumberRateNumberRate
Number & Rate of Live Births by Interpregnancy Interval and by Year,
Michigan 1989-2015
198972,706  14,046  193.233,254  457.425,406  349.4
199056,668  11,582  204.425,800  455.319,286  340.3
199142,993  9,223  214.519,267  448.114,503  337.3
199233,927  7,204  212.315,424  454.611,299  333.0
199378,460  15,930  203.036,511  465.326,019  331.6
199475,931  14,651  193.034,768  457.926,512  349.2
199572,682  12,952  178.233,451  460.226,279  361.6
199672,001  12,397  172.233,307  462.626,297  365.2
199773,124  12,609  172.433,224  454.427,291  373.2
199873,192  12,320  168.333,292  454.927,580  376.8
199971,707  11,979  167.132,654  455.427,074  377.6
200073,978  12,586  170.133,557  453.627,835  376.3
200173,370  12,141  165.533,535  457.127,694  377.5
200271,010  12,015  169.232,598  459.126,397  371.7
200370,682  12,346  174.732,194  455.526,142  369.9
200469,798  12,179  174.531,836  456.125,783  369.4
200569,035  12,257  177.531,245  452.625,533  369.9
200669,679  12,448  178.631,696  454.925,535  366.5
200767,750  12,253  180.930,820  454.924,677  364.2
200864,124  11,969  186.728,937  451.323,218  362.1
200962,003  11,106  179.128,358  457.422,539  363.5
201060,890  10,468  171.927,967  459.322,455  368.8
201160,929  10,425  171.127,593  452.922,911  376.0
201260,802  10,279  169.127,445  451.423,078  379.6
201362,125  10,415  167.627,957  450.023,753  382.3
201463,534  10,851  170.828,413  447.224,270  382.0
201565,134  11,144  171.129,212  448.524,778  380.4

Notes:

Rates are per 1,000 multiparous mothers.
Inter-pregnancy Interval (IPI) is the time in months between the date of last menstrual period of current pregnancy and the date of previous live birth among multiparous mothers. (This definition of IPI is sometimes called the "birth-to-birth interval, minus 9 months.")

Short IPI
The IPI is less than 12 months.

Source: 1989 Michigan Birth Certificate Registry;1990-2015 Geocoded Michigan Birth Certificate Registries.
Division for Vital Records & Health Statistics, Michigan Department of Health & Human Services