Multiple Births in Kansas, 1989-1998


The number of births in multiple deliveries for Kansans climbed to 1,081 in 1998, including 1,015 twins, 59 triplets, and 7 born in other higher order multiple deliveries. This represents a 2.0 percent increase in the number of multiple births from 1997, and a 22.1 percent increase from 1989 (see Figure 1). In 1998 the multiple birth rate had grown 23.1%, from 22.9 per 1,000 live births in 1989. Over the same time period, the twin birth rate increased 19.4 percent (from 22.2 per 1,000 live births - see Figure 2), and the triplet birth rate rose 114.3 percent (from 0.7 per 1,000 live births). There were no reported births of quadruplets or other higher order multiple births to Kansas residents from 1989-1993 (see the following table).
 

Multiple Births, Kansas, 1989-1998

         

Number of 

Higher Order

Total

 
 

Number of 

Twin

Number of

Triplet

Other

Multiple**

Number of

Multiple

Year

Twins

Birth Rates*

Triplets

Birth Rates*

Multiples

Birth Rates***

Multiples

Birth Rates*

1989 

858 

22.2 

27 

0.7 

-

69.9 

885 

22.9 

1990 

881 

22.7 

15 

0.4 

-

38.6 

896 

23.1 

1991 

828 

22.0 

21 

0.6 

-

55.8 

849 

22.6 

1992 

898 

23.7 

43 

1.1 

-

113.6 

941 

24.9 

1993 

863 

23.1 

45 

1.2 

-

120.7 

908 

24.4 

1994 

847 

22.7 

40 

1.1 

120.7 

892 

23.9 

1995 

895 

24.1 

38 

1.0 

115.9 

938 

25.3 

1996 

978 

26.8 

49 

1.3 

156.1 

1035 

28.3 

1997 

1016 

27.3 

42 

1.1 

118.3 

1060 

28.5 

1998 

1015 

26.5 

59 

1.5 

172.0 

1081 

28.2 

Residence data
*Twin, Triplet, and Multiple birth rates are per 1,000 live births
**Higher order multiple births include triplets, quadruplets, etc.
***Higher order multiple birth rates are per 100,000 live births

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The 1998 rate of combined higher order multiple births, including triplets (i.e. births in greater than twin deliveries), shows an increase of 146.1 percent from 69.9 per 100,000 live births in 1989 (see Figure 3). Put another way, one in every 581 births was a triplet or other higher level multiple in 1998, compared to one in every 1431 births in 1989.

Nationally, there was a 52 percent increase in the number of twins and a 404 percent increase in the number of triplets and other higher order multiple births from 1980 to 1997. The higher order multiple birth rate of 173.6 per 100,000 live births in 1997 (comparable to Kansas' rate of 172.0 in 1998) was more than double the rate of 81.4 in 1991 and quadruple the rate of 37.0 in1980 (National Vital Statistics Report, Vol. 47, No. 18, April 29, 1999).

figure 1

The trend toward greater numbers and higher rates of multiple births can be partially attributed to fertility enhancing therapies and the tendency in recent years of women to delay childbearing until later in life, when there is a greater likelihood of bearing children in multiple births. For Kansas residents in 1989 births to women 35 years of age or older comprised 7.2 percent of live births. In 1998 those births had risen to 11.4 percent of live births.

Figure 2

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Figure 3

Material for this report was derived from summaries of birth records provided by delivering physicians to the Office of Vital Statistics. More information is available in the Annual Summary of Vital Statistics, a summary of health data collected by the State of Kansas on vital events. This publication and other information is available from the Kansas Department of Health and Environment, Public Health Informatics, Office of Health Assessment (785-296-8627).


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