Number & Rate of Live Births by Interpregnancy Interval and by Year,
Macomb County, Michigan 1989-2023

Year	Multiparous Mothers	Interpregnancy Interval
		Short IPI		IPI of 12-35 Months		IPI of 36 Months and over
		Number	Rate	Number	Rate	Number	Rate
1989	5,357	947	176.8	2,540	474.1	1,870	349.1
1990	4,575	796	174.0	2,156	471.3	1,623	354.8
1991	2,438	431	176.8	1,179	483.6	828	339.6
1992	1,331	236	177.3	633	475.6	462	347.1
1993	5,320	857	161.1	2,657	499.4	1,806	339.5
1994	5,414	913	168.6	2,618	483.6	1,883	347.8
1995	5,190	792	152.6	2,489	479.6	1,909	367.8
1996	5,328	835	156.7	2,572	482.7	1,921	360.5
1997	5,153	788	152.9	2,454	476.2	1,911	370.9
1998	5,087	784	154.1	2,418	475.3	1,885	370.6
1999	4,935	796	161.3	2,351	476.4	1,788	362.3
2000	5,306	863	162.6	2,541	478.9	1,902	358.5
2001	5,181	750	144.8	2,460	474.8	1,971	380.4
2002	5,053	812	160.7	2,397	474.4	1,844	364.9
2003	5,003	856	171.1	2,252	450.1	1,895	378.8
2004	4,936	845	171.2	2,266	459.1	1,825	369.7
2005	4,974	846	170.1	2,314	465.2	1,814	364.7
2006	5,351	923	172.5	2,432	454.5	1,996	373.0
2007	5,178	871	168.2	2,393	462.1	1,914	369.6
2008	4,872	846	173.6	2,235	458.7	1,791	367.6
2009	4,566	761	166.7	2,080	455.5	1,725	377.8
2010	4,551	645	141.7	2,089	459.0	1,817	399.3
2011	4,484	702	156.6	2,031	452.9	1,751	390.5
2012	4,589	720	156.9	2,023	440.8	1,846	402.3
2013	4,865	730	150.1	2,144	440.7	1,991	409.2
2014	4,938	835	169.1	2,135	432.4	1,968	398.5
2015	5,086	848	166.7	2,228	438.1	2,010	395.2
2016	5,196	800	154.0	2,332	448.8	2,064	397.2
2017	5,194	863	166.2	2,331	448.8	2,000	385.1
2018	5,089	829	162.9	2,283	448.6	1,977	388.5
2019	5,093	853	167.5	2,270	445.7	1,970	386.8
2020	4,979	835	167.7	2,218	445.5	1,926	386.8
2021	4,976	792	159.2	2,252	452.6	1,932	388.3
2022	4,824	772	160.0	2,150	445.7	1,902	394.3
2023	4,310	720	167.1	1,933	448.5	1,657	384.5

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;1990-2023 Geocoded Michigan Birth Certificate Registries.
Division for Vital Records & Health Statistics, Michigan Department of Health & Human Services