Age at First Birth

 

Percentage of women who gave birth by specific exact ages

 

Definition

 

1)     Percentages of women age 15-49 who had a first birth by specific exact ages.

2)     Percentage of women age 15-49 who have never given birth.

 

Coverage:

Population base: All women age 15-49 (IR file)

Time period: Current status at time of survey

 

Numerator:

1)     Number of women whose first birth was before specific exact ages (v212 < specific age)

2)     Number of women who have never gave birth (v201 = 0)

 

Denominator: Total number of women including those without a birth

 

Variables: IR file.

v201

Number of children ever born

v212

Age at first birth

v005

Woman’s individual sample weight

 

Calculation

 

Age at first birth (v212) is the difference between the birth date of the first-born child and birth date of the woman (in CMC format) grouped into categories of age at first birth in years.

 

Numerators: Number of women who gave birth by specific exact ages (15, 18, 20, 22, 25) includes women who gave birth before earlier specific ages, e.g. the number of women who gave birth before age 18 includes those who gave birth before age 15. Number of women with no births (v201 = 0) are included in a separate category.

 

Denominator: Number of all women, irrespective of marital status or whether they ever had a birth. Ever-married sample denominators are adjusted by the all women factors.

 

Numerators for each exact age category are divided by the overall denominator and multiplied by 100.

 

Handling of Missing Values

 

Not applicable—Birth dates of children and women are imputed if missing; therefore, birth dates do not have missing values.

 

Notes and Considerations

 

Percentages are not calculated for the exact ages at first birth categories by cohorts of women where the youngest member of the cohort has not yet reached the exact age of the category. For example, percentages for the cohort of women age 20-24 at the time of the survey will not be calculated for exact age categories 22 and 25 because some women without births are still in or below the exact ages and could still have first births before the specific age.

 

Resources

 

DHS-7 Tabulation plan: Table 5.9

 

API Indicator IDs:

FE_BBAG_W_A15, FE_BBAG_W_A18, FE_BBAG_W_A20, FE_BBAG_W_A22, FE_BBAG_W_A25, FE_BBAG_W_NEV

(API link, STATcompiler link)

 

MICS6 Indicator TM.2: Early childbearing

(Percentage of women age 20-24 years who have had a live birth before age 18)

 

 


 

Median age at first birth

 

Definition

 

Median age in years at birth of the first child.

 

Coverage:

Population base: All women age 15-49 (IR file)

Time period: Current status at time of survey

 

Median: Median for completed time periods

 

Variables: IR file.

v201

Number of children ever born

v212

Age at first birth

v005

Woman’s individual sample weight

 

Calculation

 

Age at first birth: Difference between birth date of first-born child and birth date of woman (in CMC format), truncated to single years of age (v212).

 

Numerators: Number of women within single age group categories. Women with no births (v201 = 0) are included in a separate category at the tail of the distribution.

 

Denominator: Number of all women, irrespective of marital status or whether they ever had a birth. Ever-married sample denominators are adjusted by the all women factors.

 

Numerators for each single age group category are divided by the same denominator and multiplied by 100 to obtain percentages.

 

Medians are calculated from cumulated single year of age percent distributions of age at first birth. Median is linearly interpolated between the age values by which 50 percent or more of the women had a first birth. See Median Calculations in Chapter 1.

 

Handling of Missing Values

 

Not applicable—Birth dates of children are imputed if missing; therefore birth dates do not have missing values.

 

Notes and Considerations

 

Since the difference in mother’s and child’s birth dates are truncated to years, difference between them is taken as including up to next completed year of age (cumulated percentage for women with a difference of 19 years includes all women below 20 years of age at first birth). Therefore an adjustment is made to the interpolated median by increasing the interpolated value by one year.

 

Since the median is based on all women including those without a birth, there may not be a median for younger cohorts of women (since fewer than 50 percent of the cohort may have had a birth).

 

Resources

 

DHS-7 Tabulation plan: Tables 5.9 and 5.10

 

API Indicator IDs: FE_AAFB_W_M20, FE_AAFB_W_M25

(API link, STATcompiler link)