TRENDS IN BIRTH SPACING

Monday, 25th of June 2012

• TRENDS IN BIRTH SPACING

By Shea Rutstein; full text is at http://www.measuredhs.com/pubs/pdf/CR28/CR28.pdf

Executive Summary

The purpose of this comparative report is to examine the levels and trends of birth intervals asdocumented in the Demographic and Health Surveys (DHS). The interval between births has been shown in numerous studies to substantially affect the mortality, birth size and weight, and nutritional status of children, and the risk of pregnancy complications for mothers. This report presents information on the lengths of actual and preferred birth intervals, trends in actual and preferred birth intervals, the difference between actual and preferred birth intervals, and trends in the difference. Additionally, the report gives information on the desire for more children and met and unmet need for contraception for spacing births, at the time of the survey.

Using the birth history information from the DHS woman’s questionnaire, the study calculates the number of months between births, based on the birth date. This report covers 72 countries with DHS surveys representing 371,768 birth intervals. The latest surveys range in date from 1985 to 2008. Overall, the median birth interval is 32.1 months.

Children born after intervals of less than 24 months are considered at a higher risk for childmortality and undernutrition, and mothers with those intervals are at a higher risk of birth complications.

Overall, almost one in four births occurred after an interval of less than 24 months. Children born after intervals of less than 36 months are also considered to have an elevated risk of mortality and malnutrition.

More than half (57 percent) of children are born after such intervals. Long birth intervals also entail increased risk for perinatal and neonatal mortality and for pregnancy complications. Overall, 12 percent of children were born after an interval of 60 or more months. Birth intervals between 36 and 59 months entail lower risk. No country has more than half of births occurring in this lower-risk category. Among the most recent DHS surveys in each country, the average percentage of births in the lower-risk interval is 31 percent. Thus more than two-thirds of non-first births occur in a higher-risk category.

Forty-six countries have more than one DHS survey, which allows for the examination of trendsin birth intervals. The trends are based on comparing the first DHS survey for a country with the latest survey. For the 46 countries together, the median length of the birth interval increased by 3.1 months between the first and last surveys. On a per year basis, this increase was one-quarter of a month. The increases in median interval length are accompanied by decreases in the proportions of children born after intervals of less than 24 months and less than 36 months, and increases in the proportions born after intervals of 60 or more months. For the 46 countries combined, the rate of change in the proportion of intervals of less than 24 months is -0.38 percentage points per year, -0.69 percentage points per year for intervals shorter than 36 months, and +0.40 percentage points per year for intervals of 60 or more months.

In the DHS, to ascertain preferred birth intervals, women were asked at the time of the surveywhether they wanted another birth. Women who did want another birth were asked how long they would want to wait until they had the next birth. Women who were pregnant at the time of interview were asked how long after the birth of the child of the current pregnancy they would want to wait to have another birth. For all the countries together, the most recent surveys indicate that mothers would prefer a median birth interval of 41.5 months, over 9 months longer than their actual median interval in the five years preceding the surveys. Only 16 percent of mothers prefer an interval shorter than 24 months, but 9 percentage points more of them have such a short interval. Overall, only 14 percent of mothers had their latest birth within 3 months of their preference. More than 6 of 10 mothers preferred a birth interval longer by 4 or more months than their actual interval but about one in four women preferred an interval shorter than their actual interval.

The length of birth intervals that women prefer has not changed much over time. On average, themedian preferred interval increased by 0.15 months implying an average increase of 1.5 months per decade.

The demand for contraception for spacing births includes current use of contraception by marriedwomen who want another birth in two or more years from the date of the survey, plus women with an unmet need for spacing. Over all the surveys, about one-quarter (25.5 percent) of currently married women have a demand for contraception in order to space the next birth. The demand for contraception for spacing has increased at an annual average rate of 0.22 percentage points (+2.2 points per decade).

While almost half of the demand is unsatisfied (46.3 percent), the percentage unsatisfied has declined at a per decade rate of 12.1 percentage points.

While substantial proportions of births still occur after intervals that are too short for the health of infants and their mothers and more than half of births occur less than three years after the mother’s previous birth, this proportion has decreased over time, at a rate of about 7 percentage points per decade.

Preferred birth intervals are still much longer than actual intervals, but the rate of increase in the length of actual intervals exceeds the increase in preferred intervals, so the gap between the two is shrinking.