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Ministry of Health

Quartely Digest
Volume 6 - Number 1 July 1996
Summary Article Tables and Figures
Increased Maternal Age and the Outcome of Pregnancy
(An eight year population based study, British Columbia, 1987 - 1994)

Index of Tables and Figures

National and Provincial Review: 1982 - 1992

Table 1
Live Births to Older Mothers as Percentage of All Live Births
Canada, Provinces and Territories
1982 to 1992

MaternalYear
Age19821983198419851986198719881989199019911992
Canada30 - 3418.8%19.6%20.6%21.6%22.3%23.4%24.2%25.1%26.0%26.9%27.9%
35+4.9%5.6%6.0%6.4%6.9%7.4%7.9%8.3%8.8%9.3%9.9%
NF30 - 34---------19.9%20.8%
35+---------6.2%5.9%
PE30 - 3418.5%17.4%18.4%18.4%19.6%20.2%21.2%22.5%22.8%23.0%25.8%
35+5.5%6.5%6.0%6.5%8.3%6.8%6.9%6.8%7.3%9.0%7.8%
NS30 - 3416.0%17.1%18.2%19.0%20.7%20.4%21.1%22.2%23.5%23.5%24.6%
35+3.9%5.1%5.2%5.8%5.6%6.4%6.6%6.7%7.6%7.7%8.4%
NB30 - 3414.4%15.3%15.1%16.8%16.7%20.1%20.6%19.3%19.9%20.5%21.3%
35+3.6%3.8%4.2%4.0%4.7%5.3%6.0%4.8%5.3%5.5%6.5%
PQ30 - 3419.6%19.5%20.2%20.9%21.2%22.3%23.1%24.2%25.2%26.5%27.6%
35+5.0%5.3%5.6%5.8%6.2%6.4%6.9%7.0%7.6%8.0%8.7%
ON30 - 3420.5%21.5%22.4%23.4%24.1%25.0%25.5%26.7%27.7%29.0%30.0%
35+5.5%6.5%7.0%7.4%7.9%8.5%9.1%9.6%9.9%10.7%11.3%
MB30 - 3416.8%18.0%18.9%20.3%20.9%21.4%21.6%22.7%23.0%23.7%24.5%
35+4.6%5.3%5.5%5.9%6.4%6.9%7.1%7.7%7.8%7.9%8.9%
SK30 - 3413.3%14.2%15.6%16.7%17.4%19.4%19.4%20.1%21.6%21.6%23.0%
35+3.5%3.7%3.9%4.1%4.6%4.7%5.2%5.4%6.0%6.7%7.1%
AB30 - 3415.9%17.5%19.2%20.2%21.9%23.0%23.8%25.2%25.5%25.9%27.3%
35+3.9%4.7%5.0%5.4%5.7%6.4%7.1%7.6%8.4%9.1%9.5%
BC30 - 3419.8%21.5%22.2%23.2%24.3%25.3%26.0%26.7%27.5%28.3%29.0%
35+4.8%6.2%6.8%7.4%8.1%8.7%9.6%9.9%10.6%11.0%11.7%
YT30 - 3418.5%18.1%22.5%21.8%23.0%25.7%26.7%27.1%27.5%25.5%25.7%
35+3.0%5.7%6.4%6.9%9.3%9.4%8.3%9.4%10.6%11.4%13.6%
NT30 - 3413.7%13.9%16.0%16.0%16.0%15.7%16.6%15.0%16.6%17.4%17.8%
35+5.6%6.6%5.6%4.6%5.7%4.9%6.2%5.8%5.3%6.5%7.0%
Source: Statistics Canada, Annual Publications of Births and Deaths, 1982 to 1992.

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Figure 1
Percentage of Live Births to Elderly Gravidae,
Canada and Selected Provinces, 1982 to 1992

Percentage of Live Births to Elderly Gravidae
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Notes to Table 1 and Figure 1

  • Nationally, the proportion of live births to women aged 35 and older increased from 4.9% in 1982 to 9.9% in 1992, doubling over the 10 year period. In 1992, the proportion of live births to women aged 35 and older in British Columbia was 2.4 times the proportion in 1982, a sharp increase from 4.8% to 11.7%. The proportion of live births to older women continued to increase in BC, reaching 14.0% in 1995. Apart from 1982, the annual proportions of "elderly" mothers in BC was greater than the National percentages.
  • From 1982 to 1992, percentages of live births to women aged 35 and older increased steadily in all provinces and territories except the Northwest Territory, where the percentages remained relatively stable. The percent of live births to women aged 35 and older in BC was the fifth highest in 1982, and was behind the Northwest Territory (5.6%), Ontario (5.5%), Prince Edward Island (5.5%), and Quebec (5.0%). By 1992, the percentage in BC was ranked second highest (11.7%) and was slightly lower than the percentage in the Yukon (13.6%).
  • Over the 1982 - 1992 period, the percentage in the Yukon rose from the lowest in 1982 (3.0%) to the highest in 1992 (13.6%), compared with all other provinces and territories.
  • From 1985 to 1992, the annual percentages of live births to women aged 35 and older in BC were above the percentages of all other provinces and territories except for the Yukon. The annual percentages in Ontario were slightly lower than the percentages in BC.

Table 2
Age Specific Fertility Rates by Mother's Age
Canada, Provinces and Territories
1981 to 1992

Age Group
30-34
Canada PE NS NB PQ ON MB SK AB BC YT NT
1982 68.6 77.4 59.7 53.8 62.8 71.5 69.1 73.0 74.7 72.4 79.1 91.3
1983 70.5 70.6 62.2 55.8 61.3 74.6 73.3 72.0 79.0 75.7 81.7 98.1
1984 73.3 76.6 64.7 53.7 62.5 79.1 75.8 75.8 81.5 78.4 97.5 104.5
1985 74.6 77.1 65.8 57.1 62.0 81.3 80.8 77.7 86.0 79.5 77.7 95.4
1986 75.6 76.8 70.2 53.9 61.6 82.7 81.6 76.3 82.8 80.1 80.4 103.4
1987 76.3 77.2 66.6 62.7 62.7 83.5 80.9 80.2 85.2 81.4 87.8 103.9
1988 78.7 79.1 67.8 63.7 65.2 86.5 81.6 78.0 86.3 84.1 99.3 107.5
1989 83.7 81.9 72.8 59.8 72.0 91.6 86.8 80.4 92.7 86.0 90.7 90.5
1990 88.1 84.5 78.0 62.6 78.6 96.3 87.8 84.8 91.2 90.2 108.3 105.5
1991 83.6 80.5 69.3 59.6 77.9 90.5 87.9 80.0 86.5 84.7 89.1 101.1
1992 85.3 88.5 70.5 61.3 80.3 92.1 86.4 83.3 88.3 85.3 79.5 94.8
Age Group
35-39
Canada PE NS NB PQ ON MB SK AB BC YT NT
1982 20.2 24.8 15.7 13.4 17.7 21.7 21.9 20.3 21.9 21.5 19.8 48.0
1983 20.5 25.7 18.6 14.0 16.5 22.6 21.9 19.9 23.1 22.6 33.3 55.0
1984 21.5 23.0 18.1 15.4 17.1 23.9 22.8 20.1 23.4 24.7 30.0 39.4
1985 21.8 24.0 19.1 13.2 17.1 24.3 23.3 20.7 23.8 25.4 29.0 33.5
1986 22.6 29.4 18.1 14.8 17.4 25.5 24.6 22.2 24.6 25.4 38.0 37.6
1987 23.7 25.4 19.7 16.6 17.3 27.4 26.0 21.0 26.2 27.2 34.2 33.9
1988 25.4 26.5 21.1 17.8 18.9 29.2 25.9 23.0 27.7 29.7 32.5 38.9
1989 27.0 21.7 21.1 14.1 20.5 31.7 28.7 22.6 29.6 30.1 33.8 36.8
1990 28.8 27.0 24.4 15.7 23.1 33.0 28.8 24.4 31.0 32.4 42.4 34.7
1991 28.3 30.6 22.1 15.2 23.0 32.8 27.8 24.8 31.2 30.7 35.0 43.3
1992 28.9 24.2 23.1 16.9 23.9 33.6 29.3 24.6 30.4 31.4 37.4 39.9
Note: Age Specific Fertility Rates for maternal age group 40+ were not included as the rates were very small.
Rate of live births per 1,000 women in the specified age group. [Back to Table of Contents] [Back to Quarterly Digest]

Figure 2
Age Specific Fertility Rates, (ASFR) (Age 35 - 39)
Canada and Selected Provinces, 1982 to 1992

Age Specific Fertility Rates
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Notes to Table 2 and Figure 2

  • For women aged 35 - 39, the national age specific fertility rate rose from 20.2 livebirths per 1,000 women in 1982 to 28.9 in 1992, a 43% increase in 11 years. The corresponding rate for BC was 21.5 in 1982, and 31.4 in 1992, an approximate 46% increase. Increasing trends in annual age specific fertility rates to women aged 35 - 39 were observed in all provinces and territories except for the Northwest Territory where the annual rate declined from 48.0 in 1982 to 39.9 in 1992 and in PEI where the annual rates fluctuated.
  • From 1982 to 1992, the annual age specific fertility rates for women aged 35 - 39 in BC were above the national rates. Compared with the rest of the provinces and territories, the annual rate in BC was ranked sixth highest in 1982 and fourth highest in 1992.
  • Correspondingly, the ASFR for women aged 30-34 increased nationally and in BC.

British Columbia Birth Review, 1987-1994

Table 3
Live Births by Age of Mother
British Columbia, 1987 to 1994

Age of Mother
<2020 - 2930 - 3435+N.S.Total
YearNo.%No.%No.%No.%No.No.%
19872,2045.325,25060.610,56225.43,6388.7141,655100.0
19882,4005.625,22858.811,16526.04,1199.6142,913100.0
19892,5495.825,07657.511,65126.74,3099.9043,585100.0
19902,6075.825,36456.012,50627.64,83210.72445,333100.0
19912,6755.924,79854.712,83828.34,98311.01845,312100.0
19922,5995.724,46453.513,28229.15,34711.72045,712100.0
19932,4945.424,05852.313,52929.45,87912.82745,987100.0
19942,5705.523,99251.214,02529.96,28913.4546,881100.0
1987 - 199420,0985.6198,23055.599,55827.939,39611.096357,378100.0
Note: N.S. - Not Stated.
Percentage of live births in the specific year(s) [Back to Table of Contents] [Back to Quarterly Digest]

Figure 3
Percentage of Live Births by Age of Mother,
British Columbia, 1987 and 1994

Percentage of Live Births by Age of Mother
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  • From 1987 to 1994, there were 375,378 live births in BC. Of the total live births, 55.5% were born to women aged 20 - 29, 27.9% to women aged 30 - 34, and 11.0% to women aged 35 and older.
  • The annual percentage of live births born to mothers age 20 - 29 declined from 60.6% in 1987 to 51.2% in 1994, while the corresponding annual percentage to mothers age 35 and older rose from 8.7% in 1987 to 13.4% in 1994, a 54% increase in 8 years.
  • An increasing trend in birth rate was also observed in maternal age group 30 - 34. Over the time period, mothers in this age group also increased both in terms of number of births and percentage of total live births.

Table 4
Stillbirths* by Age of Mother
British Columbia, 1987 to 1994

Age of Mother
<2020 - 2930 - 3435+N.S.Total
YearNo.RateNo.RateNo.RateNo.RateNo.No.Rate
1987198.51716.7747.0339.002977.1
1988208.31616.3706.2419.902926.8
1989176.61917.6756.4368.303197.3
1990207.61666.5715.6357.202926.4
1991269.61496.0836.4377.422976.5
1992166.11586.47556.0468.502956.4
1993124.81315.4926.8559.322926.3
19942610.01385.7896.3579.013116.6
1987 - 19941567.71,2656.36296.33408.652,3956.7
Note: Rate per 1,000 total births in the specific year(s) and maternal age group.
N.S. - Not Stated.
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  • Of the 377,773 total births, there were 2,395 stillbirths during the 8 year period. With a rate of 8.6 per 1,000 total births, mothers aged 35 and older had a greater risk of having a stillborn infant, compared with all mothers younger than 35. The stillbirth rate to teenage mothers was 7.7, slightly higher than the rates to mothers aged 20 - 29 and 30 - 34.
  • The least risk of stillbirth was for women aged 20 - 29 and 30 - 34 with rates of 6.3 for both groups.

Table 5
Age Specific Fertility Rates and Total Fertility Rates*
British Columbia, 1987 to 1994

Age of Mother
15-1920 - 2930 - 3435 - 44
YearNo.ASFRNo.ASFRNo.ASFRNo.ASFRTFR
19872,18220.625,25097.010,56277.13,62916.01,618.6
19882,37422.325,22897.811,16579.74,10717.31,661.6
19892,52423.825,07696.811,65180.84,29517.21,662.6
19902,57624.125,36497.412,50684.04,82218.31,697.0
19912,64024.624,79895.312,83884.24,96818.01,677.1
19922,57023.724,46494.413,28286.05,33618.81,681.1
19932,46222.424,05893.113,52986.25,85519.91,673.7
19942,53622.523,99292.114,02587.36,27220.61,676.1
Note: Age specific fertility rate (ASFR) - live births per 1,000 women in specific childbearing age group.
Total Fertility Rate (TFR) - sum of ASFRs (14 to 44 years) multiplied by the number of years in each age group.
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  • During the 8-year period, the annual age specific fertility rates for maternal age group 20-29 declined from 97.0 to 92.1, a 5.1% decrease. For women aged 30 - 34, the corresponding rate increased from 77.1 in 1987 to 87.3 in 1994. Among women aged 35 - 44, the rate increased by 28.8% from 16.0 in 1987 to 20.6 in 1994.
  • Although there was a relatively large percentage increase in fertility for women over 29 years of age, this was offset by the smaller percentage decrease among women aged 20 - 29. This resulted in little appreciable change in the total fertility rate (TFR) because of the large number of births to women age 20 - 29.

Table 6
Live Births by Birth Order* and Age of Mother
British Columbia, 1987 to 1994

Birth Order
1st 2nd 3rd+
Maternal Age
Year <20 20-29 30-34 35+ <20 20-29 30-34 35+ <20 20-29 30-34 35+
1987 No. 1,844 11,566 3,104 883 329 9,374 4,255 1,277 31 4,316 3,210 1,484
%* 83.6 45.7 29.3 24.1 14.9 37.0 40.1 34.9 1.4 17.0 30.3 40.5
1988 No. 2,044 11,942 3,322 989 317 8,906 4,388 1,472 39 4,388 3,464 1,667
%* 85.1 47.2 29.6 23.8 13.2 35.2 39.1 35.5 1.6 17.3 30.9 40.2
1989 No. 2,140 11,820 3,563 1,087 351 8,980 4,517 1,563 42 4,183 3,542 1,652
%* 84.4 47.1 30.6 25.1 13.8 35.8 38.7 36.2 1.7 16.7 30.4 38.2
1990 No. 2,201 12,469 3,887 1,213 368 8,910 4,899 1,696 38 3,989 3,729 1,933
%* 84.3 49.0 31.0 25.0 14.1 35.0 39.0 34.9 1.5 15.7 29.7 39.8
1991 No. 2,250 12,128 3,997 1,279 388 8,696 4,980 1,771 37 3,985 3,872 1,936
%* 83.9 48.8 31.0 25.5 14.5 35.0 38.6 35.4 1.4 16.0 30.0 38.7
1992 No. 2,164 12,139 4,202 1,381 396 8,491 5,275 1,928 39 3,841 3,814 2,046
%* 83.3 49.5 31.5 25.7 15.2 34.6 39.6 35.9 1.5 15.7 28.6 38.1
1993 No. 2,031 12,339 4,618 1,621 416 8,144 5,179 2,107 37 3,561 3,703 2,129
%* 81.7 51.2 34.1 27.5 16.7 33.8 38.2 35.8 1.5 14.8 27.3 36.2
1994 No. 2,116 12,344 4,924 1,774 407 8,143 5,427 2,243 47 3,503 3,650 2,230
%* 82.2 51.4 35.1 28.3 15.8 33.9 38.7 35.8 1.8 14.6 26.0 35.6
1987 No. 16,790 96,747 31,617 10,227 2,972 69,644 38,920 14,057 310 31,766 28,984 15,077
-1994 %* 83.5 48.7 31.7 25.9 14.8 35.1 39.0 35.6 1.5 16.0 29.0 38.1
Note: As there were live births that were either birth order unknown and/or mother's age unknown,
the sum of the annual live births may not match the annual live births published in previous tables.
* Percentages are the proportion of births by birth order within a given age group and specified year.
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Figure 4
Proportion of Birth Order for Elderly Gravidae*
British Columbia, 1987 and 1994

Proportion of Birth Order for Elderly Gravidae
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Notes to Table 6 and Figure 4

  • Over this short time period, there was an increased tendency for mothers to have their first or second child indicating a trend toward smaller families.
  • Of all elderly gravidae* in 1987 - 1994, 25.9% were 1st birth order, 35.6% were 2nd birh order, and 38.1% were 3rd+ birth order.
  • The annual percentage of first born live births for elderly primiparas increased from 24.1% in 1987 to 28.3% in 1994, while the corresponding annual percentages for elderly mothers of parity 3+ declined from 40.5% to 35.6%.

Table 7
Low Birth Weight Live Births by Age of Mother
British Columbia, 1987 to 1994

Extremely Low BirthVery Low BirthLow Birth
Weight (<500g)Weight (<1500g)Weight (<2500g)
Maternal Age
Year<2020-2930-3435+<2020-2930-3435+<2020-2930-3435+
1987No.211572221790531351,258505215
%0.090.040.050.191.000.860.851.466.134.984.785.91
1988No.5151642919794421411,229554221
%0.210.060.140.101.210.780.841.025.884.874.965.37
1989No.0186542207102391611,304574228
%0.000.070.050.121.650.830.880.916.325.204.935.29
1990No.3132930208103521641,244579266
%0.120.050.020.191.150.820.821.086.294.904.635.50
1991No.112313419093421581,161601261
%0.040.050.020.021.270.770.720.845.914.684.685.24
1992No.115742517893431281,158600286
%0.040.060.050.070.960.730.700.804.924.734.525.35
1993No.478423159114581351,186657321
%0.160.030.060.070.920.660.840.995.414.934.865.46
1994No.187728147116701251,122727381
%0.040.030.050.111.090.610.831.114.864.685.186.06
1987No.179954412331,5038053991,1479,6624,7972,179
-1994%0.080.050.050.101.160.760.811.015.714.874.825.53
Note: As there were live births with mother's age unknown,
the sum of the annual live births may not match the annual live births published in previous tables.
Percent live births in the specified year (s) and maternal age group.
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  • At the three standard categories defining low birth weight (LBW) live births [extremely low birth weight (<500g); very low birth weight (<1500g); and low birth weight (<2500g)], LBW rates were higher for women aged 35 and older, compared with the rates for women aged 20 - 29. The low birth weight (<2500 g) live birth percentage was 5.5 for women aged 35 and older, and 4.9 for women aged 20 - 29.
  • For 35+ mothers, the risk for having a LBW infant was approximately the same as for teenage mothers. However, there were almost twice as many LBW babies born to older mothers than to teenagers (2,179 vs. 1,147).

Figure 5
Low Birth Weight by Maternal Age
British Columbia, 1987 to 1994

Low Birth Weight by Maternal Age
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  • Over the 8 years, no trends were observed in annual low birth weight live birth rates for maternal age groups 20-29, 30-34, and 35+. In the teenage group, the annual rate declined from 61.3 in 1987 to 48.6 in 1994.

Table 8
Live Births by Gestational Age and Age of Mother
British Columbia, 1987 to 1994

Live Births by Gestational Age and Age of Mother

Note: As there were live births with gestational age unknown,
the sum of the annual live births may not match the annual live births published in the previous tables.
[Back to Table of Contents] [Back to Quarterly Digest]

Figure 6
Gestational Age Distribution: Elderly Gravidae vs Reference Group
British Columbia, 1987 - 1994

Elderly Gravidae vs Reference Group
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Notes to Table 8 and Figure 6

  • Over the time period, for live born infants with gestational age less than 37 weeks, the birth rate was 5.8 per 100 live births for women aged 20 - 29, and 7.2 for elderly gravidae, a 24% higher rate.
  • The pattern of risk of bearing a premature infant was similar to LBW with the highest rates among teenage and older mothers (7.7 and 7.2 respectively).
  • While the risk of having a premature infant was similarly high for teenage and older mothers, the older mothers had approximately double the number of preterm infants (2,835 vs. 1,543).
  • The post-term (gestational age > 41 weeks) live birth rate declined from 6.3 per 100 live births for women aged <20 to 5.9 for women aged 20 - 29, 4.9 for women aged 30 - 34, and 4.1 for women aged 35+. It is worth noting that the percentages of term births for maternal age groups 20 - 29 and 35+ were about the same (88.2% and 88.5% respectively). However, premature infants were more common for mothers 35+ (7.2% vs. 5.8% ), while post-term were more frequent for maternal age group 20 - 29 (5.9% vs. 4.1% ).

Table 9
Cesarean Section Live Births by Age of Mother
British Columbia, 1987 to 1994

Age of Mother
<2020 - 2930 - 3435+N.S.Total
YearNo.%No.%No.%No.%No.No.%
198729713.55,03719.92,44023.197126.708,74521.0
198836715.35,00219.82,68424.01,16028.209,21321.5
198940315.85,12520.42,78423.91,29530.109,60722.0
199036213.95,34621.12,95423.61,28926.769,95722.0
199139814.95,04420.32,91022.71,35027.169,70821.4
199235913.84,75819.43,02422.81,44527.039,58921.0
199336214.54,59819.13,02022.31,58026.989,56820.8
199432212.54,35818.23,05121.81,53524.409,26619.8
1987 - 19942,87014.339,26819.822,86723.010,62527.02375,65321.2
Note: N.S. - Maternal age not stated.
Percentage of live births in the specific year(s)
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  • The percentage of cesarean delivered live births increased with maternal age.
  • As will be shown later in this report, the "snowballing" effect of repeat cesarean only partially accounts for this higher proportion among older mothers.
  • Over the period 1987 - 1994, the cesarean rate was 19.8% (per 100 live births) for women aged 20 - 29, 23.0% for women aged 30 - 34, and 27.0% for elderly gravidae.
  • The lowest annual cesarean rates occurred in 1994 for all maternal age groups. In that year, the annual percentage of cesarean live births was 19.8% overall, 18.2% for women aged 20 -29, and 24.4% for women aged 35 or older.

Table 10
Regional Perinatal Outcome and Maternal
Complications in Elderly Gravidae, British Columbia, 1987 - 1994

Total Live
35+LBWPrematureCesarean Complications*Births
LHANo.Rate**No.Rate*No.Rate*No.Rate*No.Rate*No.
01Fernie966.222.122.12526.02627.11,557
02Cranbrook1396.242.942.92820.12014.42,255
03Kimberley578.935.323.51424.61729.8637
04Windermere598.646.835.1813.6711.9689
05Creston928.144.377.62426.13032.61,130
06Kootenay Lake278.9--13.727.4933.3302
07Nelson25012.7176.8239.25823.29337.21,962
09Castlegar807.356.367.52733.83746.31,090
10Arrow Lakes357.6--38.61337.11337.1459
11Trail1779.3105.663.44022.65933.31,908
12Grand Forks538.7611.3815.11630.21426.4609
13Kettle Valley3010.513.326.7930.0930.0287
14Southern Okanagan927.788.71010.94043.54346.71,198
15Penticton2879.5103.5258.710135.212443.23,026
16Keremeos257.9--14.0624.0520.0315
17Princeton297.426.926.9827.61241.4390
18Golden617.311.623.31524.61219.7839
19Revelstoke576.423.535.32645.62238.6884
20Salmon Arm1989.1136.6168.16130.87738.92,165
21Armstrong-Spallumcheen7711.245.256.51924.72532.5689
22Vernon3998.5174.3215.311929.812832.14,692
23Central Okanagan9569.3565.9828.625726.922623.610,296
24Kamloops6727.9497.3527.718026.821632.18,474
26North Thompson295.6310.313.413.4517.2518
27Cariboo-Chilcotin2796.1165.7186.57526.96523.34,554
28Quesnel1816.6137.2158.35228.76033.12,731
29Lillooet437.449.337.0511.61227.9582
30South Cariboo607.058.3610.01321.72338.3861
31Merritt715.568.579.93245.12433.81,300
32Hope394.7410.325.1410.31333.3823
33Chilliwack4637.0245.2306.512226.310121.86,575
34Abbotsford7286.6304.1385.218625.517123.511,090
35Langley9899.5585.9596.026426.725726.010,417
36Surrey3,1419.11845.92477.992729.590528.834,614
37Delta1,26213.4554.4907.130524.237329.69,389
38Richmond2,07215.51035.01376.660929.473035.213,378
39Vancouver8,10617.14876.06488.02,30428.43,55443.847,297
40New Westminster55811.5366.5407.214025.119835.54,835
41Burnaby2,07613.11537.41909.253025.577837.515,894
42Maple Ridge6889.0304.4476.816223.521230.87,611
43Coquitlam2,03811.61236.01467.253026.068933.817,623
44North Vancouver2,27718.3914.01205.358525.770230.812,413
45West Vancouver-Bowen Is.88630.6323.6525.925729.030534.42,896
46Sechelt28214.0227.8238.26824.18429.82,016
47Powell River1317.053.853.83526.74735.91,869
48Howe Sound2669.5134.9259.45520.76925.92,793
49Central Coast376.512.725.41027.01027.0566
50Queen Charlotte849.91011.978.32428.62327.4846
52Prince Rupert2127.4104.7167.56530.75425.52,879
54Smithers1737.274.095.23419.74928.32,404
55Burns Lake797.667.656.31924.11822.81,038
56Nechako1315.8107.696.93627.54131.32,241
57Prince George7506.3486.4608.019826.419626.111,862
59Peace River South1794.7105.6116.13419.03318.43,779
60Peace River North2566.7145.52610.24316.84417.23,824
61Greater Victoria2,19712.81346.11557.163428.962328.417,186
62Sooke4568.5265.7327.012026.313429.45,359
63Saanich54314.2234.2397.214326.312923.83,836
64Gulf Islands14818.753.496.13322.33725.0791
65Cowichan4379.6337.6409.29120.89521.74,571
66Lake Cowichan479.624.3510.61123.41225.5488
67Ladysmith1077.687.51211.22321.53431.81,414
68Nanaimo7029.6436.1557.820128.620729.57,329
69Qualicum22911.093.9135.75021.87532.82,081
70Alberni2507.1208.0208.05120.48433.63,523
71Courtenay3969.0205.1194.89022.712030.34,393
72Campbell River3017.8186.0217.07223.911036.53,873
75Mission3038.1175.6278.96922.89631.73,749
76Agassiz-Harrison599.135.158.51118.61220.3651
77Summerland8412.267.167.11619.02428.6691
78Enderby457.3--12.21635.61533.3619
80Kitimat956.433.222.13334.73031.61,494
81Fort Nelson485.636.3510.41225.01225.0851
84Vancouver Island West335.813.039.11648.51648.5573
85Vancouver Island North1346.786.0118.24130.64332.12,008
87Stikine129.0433.318.3433.3325.0134
88Terrace2185.6209.22411.06128.07534.43,882
92Nishga165.2----212.5850.0310
94Telegraph Creek129.6----18.318.3125
Unknown----------76
Provincial Total39,38611.12,2315.72,8797.410,56827.013,01833.3357,378
Note: Rate* - Rate per 100 elderly gravidae live births.
Rate** - Rate per 100 live births.
Complications* - Selected maternal complications listed in 'Methodology'.
Numbers based on 35+ mothers, except "total live births", which refers to all births.
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Map 1
Elderly Gravidae Births by Local Health Area
British Columbia, 1987 - 1994

Elderly Gravidae Births by Local Health Area
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Notes to Table 10 and Map 1

  • Live births to women aged 35 and older occurred more frequently in urban regions than in rural regions. The regional live birth rates to women aged 35 and older varied from the lowest of 4.7% (per 100 live births) in Peace River South and in Hope to the highest of 30.6% in West Vancouver-Bowen Island.
  • The top 10 regions for elderly gravidae were, by descending order following West Vancouver-Bowen Island (30.6%), Gulf Islands (18.7%); North Vancouver (18.3%); Vancouver (17.1%); Richmond (15.5%); Saanich (14.2%); Sechelt (14.0%); Delta (13.4%); Burnaby (13.1%); and Greater Victoria (12.8%).
  • In table 10, numbers and rates of low birth weight (LBW)* live births, preterm* live births, live cesarean births, and selected maternal complications were listed by Local Health Areas for women aged 35 and older. Higher rates tended to occur in rural areas. All rates were presented as rate per 100 live births to women aged 35 and older.
  • The highest LBW live birth rate (per 100 live births to women 35+) was observed in the upper north region Stikine (33.3). Queen Charlotte Island showed the second highest rate (11.9), and was followed by 7 interior regions (Grand Forks, 11.3; North Thompson, 10.3; Hope, 10.3; Lillooet, 9.3; Southern Okanagan, 8.7; Merritt, 8.5; and South Cariboo, 8.3) and 1 north-west region (Terrace, 9.2). No low birth weight live births to mothers in this age group were observed in Telegraph Creek, Kootenay Lake, Keremeos, Arrow lakes, Enderby and Nishga.
  • The regional variation in preterm live birth rates was smaller, compared with the variation in low birth weight rates. The preterm rates ranged from 2.1 in Fernie to 15.1 in Grand Forks. The top 10 regions with high preterm live birth rates were clustered in 4 interior regions (Grand Forks, 15.1; Southern Okanagan, 10.9; South Cariboo, 10.0; and Merritt, 9.9), one lower mainland region (Howe Sound, 9.4), three northern regions (Terrace, 11.0; Fort Nelson, 10.4; and Peace River North, 10.2), and two regions on Vancouver Island (Ladysmith, 11.2 and Lake Cowichan, 10.6). No preterm birth occurred in Telegraph Creek and Nishga.
  • The 10 highest cesarean live birth rates ranged from 33.3 in Stikine to 48.5 in Vancouver Island West. Seven out of the 10 regions were observed in BC's interior (Revelstoke (45.6), Merritt (45.1), Southern Okanagan (43.5), Arrow Lakes (37.1), Enderby (35.6), Penticton (35.2), and Castlegar (33.8)). Kitimat was among the top 10 regions, with its older mother cesarean birth rate of 34.7 which was ranked 8th highest.
  • Live births to mothers age 35+ with at least one of the selected maternal complications occurred in all Local Health Areas, and the rates varied from 8.3 in Telegraph Creek to 50.0 in Nishga. The regions with the ten highest rates were, in addition to Nishga, Vancouver Island West (48.5), Southern Okanagan (46.7), Castlegar (46.3), Vancouver (43.8), Penticton (43.2), Princeton (41.4), Salmon Arm (38.9), Revelstoke (38.6), South Cariboo (38.3).

First Live Births After Age 35, British Columbia, 1987-1994

Table 11
First Live Births by Age of Mother
British Columbia, 1987 to 1994

Age of Mother
<2020 - 2930 - 3435+N.S.Total
YearNo.%No.%No.%No.%No.No.%
19871,8444.4%11,56627.8%3,1047.5%8832.1%017,39741.8%
19882,0444.8%11,94227.8%3,3227.7%9892.3%118,29842.6%
19892,1404.9%11,82027.1%3,5638.2%1,0872.5%018,61042.7%
19902,2014.9%12,46927.5%3,8878.6%1,2132.7%919,77943.6%
19912,2505.0%12,12826.8%3,9978.8%1,2792.8%719,66143.4%
19922,1644.7%12,13926.6%4,2029.2%1,3813.0%1019,89643.5%
19932,0314.4%12,33926.8%4,61810.0%1,6213.5%1720,62644.9%
19942,1164.5%12,34426.3%4,92410.5%1,7743.8%121,15945.1%
1987 - 199416,7904.7%96,74727.1%31,6178.8%10,2272.9%45155,42643.5%
Note: N.S. - Not Stated.
Percentage of live births in the specific year(s) and maternal age group.
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  • The focus of this section is on women aged 35+ who are first-time mothers. Risks of adverse maternal and infant complications, although, in many cases found to increase in older mothers regardless of parity, are generally even greater among older mothers giving birth for the first time.
  • During 1987 - 1994, there were 155,426 first live births in British Columbia, nearly 44% of all live births.
  • From 1987 to 1994, a rapid increase occurred in numbers and rates of first live births to women aged 35 and older. In 1994, the percentage of first live births to women aged 35+ was 1.8 times the rate in 1987, an increase from 2.1, per 100 first live births, in 1987 to 3.8 in 1994.
  • First live birth rates for women aged 30 to 34 followed a similar pattern to that of the older women. For women aged 20 -29, the corresponding annual rates declined.

Table 12
Age Specific Fertility Rates and Total Fertility Rates in British Columbia, First Live Births,
1987 to 1994

Age of Mother
15-1920 - 2930 - 3435 - 44
YearNo.ASFR*No.ASFR*No.ASFR*No.ASFR*TFR
19871,87117.711,75545.23,17523.29034.0695.58
19882,06719.412,05746.83,40424.31,0094.2728.79
19892,18220.612,09046.73,66125.41,1234.5741.37
19902,22020.812,60148.43,94126.51,2274.6766.46
19912,27821.212,28047.24,07226.71,2974.7758.64
19922,17920.112,27847.44,28127.71,3994.9762.51
19932,05118.612,42948.14,75230.31,6885.7783.26
19942,12918.912,45447.85,08531.61,8636.1792.00
Note: Age specific fertility rate (ASFR) - first live births per 1,000 women in specific childbearing age group.
Total Fertility Rate (TFR) - sum of ASFRs (14 to 44 years) multiplied by the number of years in each age group.
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Figure 7
Age Specific Fertility Rates in British Columbia, First Births,
1987 to 1994

Age Specific Fertility Rates in British Columbia, First Births
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  • In 1994, the age specific fertility rate of first live births to women aged 35 - 44 was 1.5 times the rate in 1987, an increase from 4.0 per 1,000 women aged 35 - 44 in 1987 to 6.1 in 1994.
  • A similar trend was observed in annual age specific fertility rates of first live births to women age 30-34. The corresponding rates for women younger than 30 increased from 1987 to 1990 but decreased from 1991 to 1994.

Table 13
First Cesarean by Age of Mother
British Columbia, 1987 to 1994

Age of Mother
<2020 - 2930 - 3435+N.S.Total
YearNo.%No.%No.%No.%No.No.%
198725013.6%2,48021.4%88328.4%31836.0%03,93122.6%
198831715.5%2,54021.3%95628.8%36236.6%14,17622.8%
198934316.0%2,65822.5%1,03929.2%44140.6%04,48124.1%
199031014.1%2,81822.6%1,14029.3%42334.9%94,70023.8%
199133214.8%2,65421.9%1,09427.4%44334.6%74,53023.0%
199229213.5%2,55521.0%1,10626.3%49435.8%104,45722.4%
199329214.4%2,49120.2%1,18625.7%52732.5%174,51321.9%
199426112.3%2,40219.5%1,21824.7%55731.4%14,43921.0%
1987 - 19942,39714.3%20,59821.3%8,62227.3%3,56534.9%4535,22722.7%
Note: N.S. - Not Stated.
Percentage of first live births in the specific year(s) and maternal age group.
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  • From 1987 to 1994, cesarean rates for first live births for women in all age groups, declined.
  • The rate for women aged 35+ increased from 36.0 per 100 first live births in 1987 to 40.6 in 1989 then fluctuated but generally decreased during the next 5 years.
  • By 1994, the first cesarean rate for mothers 35+ was 31.4, a 9.2 percentage point decline compared with the rate in 1989, and a 4.6 percentage point drop compared with the rate in 1987. Similar trends were observed for maternal age groups <20, 20 - 29, and 30 - 34.

Figure 8 Rate of First Cesarean vs All Cesarean British Columbia, 1987 - 1994

Rate of First Cesarean vs All Cesarean
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  • During the 8 years, the cesarean rates of first live births increased with maternal age.
  • The increase with mother's age in cesarean rates for first live births was more pronounced than the increase of cesarean rates for all live births. This may indicate that women who delay their first childbearing are at an even greater risk of cesarean section and that increases of the proportion of C-section among older women is more than a function of the "once a section, always a section" philosophy.

Assessment of Pregnancy Outcomes

Table 14
Rate of Selected Maternal and Infant Complications by Maternal Age, Primiparas*
British Columbia, 1987 - 1994

Maternal age ( in years)
20 - 2930 - 3435+
I.Maternal Complications:No.RateNo.RateNo.Rate
1.Antepartum haemorrhage (6400- 6419)9679.943813.522221.1
2.Hypertension/Eclamsia (6420 - 6429)3,18332.51,12334.746844.5
3.Diabetes mellitus and Gestational diabetes (6480, 6488)1,58616.292928.744142.0
4.Multiple gestation (6510 - 6519)1,76818.184426.132430.8
5.Malposition and malpresentation of fetus, disproportion
and obstructed labour (6520 - 6539, 6600 - 6609)13,014132.95,444168.21,923183.0
6.Abnormality of reproductive organs ( 6540 - 6549)4664.836411.220319.3
7.Fetal abnormality affecting mother (6550 - 6569)6,02261.52,42474.996191.4
8.Abnormality of forces of labour and prolonged labour
(6610 - 6619, 6620 - 6621)3,18732.51,38142.750648.1
9.Complications of umbilical cord (6630 - 6639)1,12211.535210.911310.8
10.Obstetrical trauma (6640 - 6659)7257.42848.8716.8
11.Postpartum haemorrhage (6660 - 6663)1,03310.532910.2979.2
Total with one or more of above26,713272.711,250347.54,342413.2
II.Perinatal Complications:
1.Slow fetal growth, SGA*, and fetal malnutrition* (7640 - 7649)1,96420.167620.928427.0
2.Birth trauma (7670 - 7679)3103.21163.6353.3
3.Intrauterine hypoxia and birth asphyxia (7680 - 7689)18,154185.46,132189.42,088198.7
4.Respiratory conditions of fetus and newborn (769, 7700 - 7709)5505.61554.8514.9
5.Isoimmunization disorders and perinatal jaundice (7730 - 7747)400.490.380.8
Total with one or more of above21,109215.57,116219.82,481236.1
IIICongenital Anomalies
1.Congenital anomalies of brain, nervous system
and spinal cord (7400 - 7429)1161.2300.980.8
2.Congenital anomalies of ear, face and neck ( 7440 - 7449)850.9270.860.6
3.Congenital anomalies of heart (7450 - 7469)961.0290.9151.4
4.Congenital anomalies of respiratory system (7480 - 7489)270.330.180.8
5.Musculoskeletal anomalies (7540 - 7569)6726.92277.0686.5
6.Chromosomal anomalies (7580 - 7589)700.7381.2232.2
7.Total with one or more of all anomalies (7400 -7799)38,431392.413,519417.64,648442.3
IV.Cesarean Section21,055215.08,895274.83,647347.0
V.Newborn outcome
1.Low birth weight (<2500 g)6,03161.62,31471.595891.2
2.Pre-term ( <37 weeks gestation)6,67968.22,77285.61,105105.1
3.Stillbirth6556.72357.310510.0
Note: Small for Gestational Age (SGA) code(s) applied to infants with inappropriate weight for their gestation (based on Lobchenko growth chart, Lobchenko, 1963) and/or manifestation of malnutrition.
Rate per 1,000 total first births in the specified maternal age group.
Individuals with more than one condition within a category counted only once in that category.
However, an individual with conditions in more than one category were counted in each category. within a category counted only once in that category.
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Table 15
Rate of Selected Maternal and Infant Complications by Maternal Age, Multiparas*
British Columbia, 1987 - 1994

Maternal age ( in years)
20 - 2930 - 3435+
I.Maternal Complications:No.RateNo.RateNo.Rate
1.Antepartum haemorrhage (6400 - 6419)1,21111.789813.147816.2
2.Hypertension/Eclamsia (6420 - 6429)1,07710.488812.957219.4
3.Diabetes mellitus and Gestational diabetes (6480, 6488)1,36813.31,62323.61,10237.3
4.Multiple gestation (6510 - 6519)2,27822.11,55922.759720.2
5.Malposition and malpresentation of fetus, disproportion
and obstructed labour (6520 - 6539, 6600 - 6609)5,17350.14,02358.61,92665.2
6.Abnormality of reproductive organs ( 6540 - 6549)6,61164.14,95972.22,33879.2
7.Fetal abnormality affecting mother (6550 - 6569)3,24931.52,27433.11,18040.0
8.Abnormality of forces of labour and prolonged labour
and obstructed labour (6610 - 6619, 6620 - 6621)1,26512.393813.744114.9
9.Complications of umbilical cord (6630 - 6639)1,05010.272710.633111.2
10.Obstetrical trauma (6640 - 6659)4684.53435.01464.9
11.Postpartum haemorrhage (6660 - 6663)1,0119.85117.41946.6
Total with one or more of above19,905192.915,217221.67,582256.8
II.Perinatal Complications:
1.Slow fetal growth, SGA*, and fetal malnutrition* (7640 - 7649)1,45914.184712.341914.2
2.Birth trauma (7670 - 7679)1781.71001.5481.6
3.Intrauterine hypoxia and birth asphyxia (7680 - 7689)14,490140.49,792142.64,416149.6
4.Respiratory conditions of fetus and newborn (769, 7700 - 7709)4154.02333.4883.0
5.Isoimmunization disorders and perinatal jaundice (7730 - 7747)790.8430.6200.7
Total with one or more of above16,647161.311,048160.95,006169.6
IIICongenital Anomalies
1.Congenital anomalies of brain, nervous system
and spinal cord (7400 - 7429)1151.1691.0240.8
2.Congenital anomalies of ear, face and neck ( 7440 - 7449)970.9430.6210.7
3.Congenital anomalies of heart (7450 - 7469)991.0440.6260.9
4.Congenital anomalies of respiratory system (7480 - 7489)270.3170.290.3
5.Musculoskeletal anomalies (7540 - 7569)4864.73455.01354.6
6.Chromosomal anomalies (7580 - 7589)800.8861.3953.2
7.Total with one or more of all anomalies (7400 -7799)33,987329.323,201337.810,692362.2
IV.Cesarean Section18,598180.214,197206.77,056239.0
1.First cesarean section4,93347.83,63853.01,99767.6
2.Repeat cesarean section13,665132.410,559153.85,059171.4
V.Newborn outcome
1.Low birth weight (<2500 g)5,34251.83,34948.81,59253.9
2.Pre-term ( <37 weeks gestation)6,39762.04,07559.32,11471.6
3.Stillbirth6035.83925.72358.0
Note: Small for Gestational Age (SGA) code(s) applied to infants with inappropriate weight for their gestation
(based on Lobchenko growth chart, Lobchenko, 1963) and/or manifestation of malnutrition.
Rate per 1,000 total second+ births in the specified maternal age group.
Individuals with more than one condition within a category counted only once in that category.
However, an individual with conditions in more than one category were counted in each category. within a category counted only once in that category.
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Notes to Tables 14 and 15

  • Of the 11 selected categories of maternal complications, older mothers showed higher rates in 8 of the listed conditions. The higher rates were more pronounced among primiparas age 35+. Overall, in terms of total selected conditions, 35+ primiparas experienced a 52% higher rate and 35+ multiparas had a 31% higher rate than the respective 20-29 year old mothers.
  • With the exception of multiple gestation* among multiparous mothers, the rates of antepartum haemorrhage;hypertension/eclamsia; diabetes; multiple gestation; malposition and malpresentation of fetus, disproportion and obstructed labour; abnormality of reproductive organs; fetal abnormality affecting mother; and abnormality of forces of labour and prolonged labour increased with maternal age. Increases by mother's age of these maternal complications were more pronounced in primiparous women.
  • For primiparous women aged 35 and older, the rate of abnormality of reproductive organs was about 4 times the rate for primiparous women aged 20 to 29, an increase from 4.8 to 19.3 per 1,000 age group specific total births. Similar differences were also observed among multiparous women although the increase in rate was much smaller (64.1 vs. 79.2).
  • The multiple gestation* rate for the primiparous group was 18.1 for women aged 20 - 29, 26.1 for women aged 30 - 34, and 30.8 for women aged 35 and older. No substantial changes were observed for multiparas. This higher risk of twins or triplets+ among older women having their first child may reflect a greater use of fertility drugs.
  • Diabetes, hypertension and toxemia (eclampsias) may manifest early in the pregnancy and require careful and more frequent monitoring. These conditions also complicate the delivery process and threaten the health of the infant. With increasing maternal age there were higher rates of diabetes and hypertension/eclampsias. For elderly primiparas, the rate of diabetes was 2.6 times the rate of the 20-29 primiparas (42.0 vs. 16.2). With a rate of 44.5, hypertension/eclampsias among primiparous mothers age 35+ was 1.4 times the rate for women age 20-29. Higher rates of both these condition categories were also noted among elderly multiparas relative to the 20-29 age group.
  • Higher incidence rates, for both slow fetal growth and fetal malnutrition and intrauterine hypoxia and birth asphyxia, were only observed in primiparas aged 35 or older. With the exception of birth asphyxia, rates of the selected perinatal conditions were relatively small.
  • The rates of chromosomal anomalies, of which most of the cases were Down's syndrome, were higher among older women. The rate increased from 0.7 for primiparas aged 20 - 29 to 2.2 for primiparas aged 35 and older, and from 0.8 for multiparas aged 20 - 29 to 3.2 for multiparas aged 35 or older. That is, regardless of parity, women age 35 and older were 3 to 4 times more likely than a mother age 20-29 to have an infant with a chromosomal defect. This may also indicate that the risk of chromosomal anomalies increases along with both maternal age and number of parity. However, for all age and parity groups, the actual incidence was small.
  • The rate of congenital anomalies overall increased slightly with mothers age regardless of parity. However, for many of the more serious defect categories, there was no or very little increase. This may reflect the use and availability to older mothers of amniocentesis and possible abortion.
  • A noticeable association between maternal age and cesarean birth was observed in both parity groups. For single parity, the rate was 215.0 per 1,000 total first births among women aged 20-29, 274.8 for women aged 30 - 34, and 347.0 for women aged 35 and older. That is, at least 1 out of 3 first-born infants of women age 35+ were delivered by cesarean compared to just under 1 in 5 for women age 20-29. Similar results were noted for the multiparous group.
  • The overall rate of C-section was higher for primiparas than for multiparas within all age groups. However, for multiparas, the rate of repeat cesarean was almost 3 times the first C-section rate for all age groups. That is, to a large degree, repeat section accounts for the high rate among multiparous older mothers.
  • The stillbirth rate was higher for maternal age 35 and older compared with the rate for maternal age 20 - 29. The rate increased from 6.7 for primiparas aged 20 - 29 to 10.0 for primiparas aged 35+ and from 5.8 for multiparas aged 20 - 29 to 8.0 for multiparas aged 35 or older. Women aged 30 - 34 did not appear to be at increased risk for stillbirth regardless of parity.