Table of Contents
Chapters
- Fertility Continues to Decline
- Contraceptive Use
- Contraceptive Method Mix
- Awareness and Availability of Contraception
- Other Direct Influences on Fertility
- Age at First Marriage
- Postpartum Insusceptibility
- Induced Abortion
- Infertility
- Comparing the Direct Influences
- Fertility Preferences
- Young Women
- Child Survival and Health
- Maternal Health
Highlights
- Is fertility decline slowing?
- The impact of contraception
- Intentions to use family planning
- Injectables becoming popular
- Desired family size falling
- Premarital sex: New findings
- How AIDS affects child survival
- Maternal care falls short
Published by the INFO Project, Center for Communication Programs, The Johns Hopkins University Bloomberg School of Public Health, 111 Market Place, Suite 310, Baltimore, Maryland 21202, USA
Volume XXXI, Number 2,
Spring 2003
Series M, Number 17
Special Topics
Other Direct Influences
on Fertility
Along with contraceptive use, several other factors influence fertility levels directly (17). These “proximate determinants” of fertility include women’s age at first marriage or first entry into any union (legal, consensual, or otherwise), the length of the period of postpartum insusceptibility to conception, and induced abortion.
These factors are especially important in explaining fertility levels and fertility declines where access to family planning information and services is poor and thus contraceptive use has not played an important role (15). Some researchers contend that, as contraceptive use becomes so widespread that substantial further increases are unlikely, the other proximate determinants will play relatively more important roles in future fertility changes (48).
In addition to these direct factors, of course, many other factors—social, economic, and cultural factors and family planning program effort—influence fertility. These, however, are indirect in their influence. They affect fertility by affecting one or more of the proximate determinants. For example, increases in women’s status and educational achievement are indirect factors. They often increase the age at first marriage and the use of contraception, two of the factors that affect fertility directly.
Age at First Marriage
The age at which a woman first experiences sexual intercourse and is thus at risk of pregnancy and childbearing has an important effect on fertility: the older her age, the lower her potential lifetime fertility. Although some childbearing occurs before marriage, the age at marriage (or, in some countries, age at the start of a consensual union) often represents the beginning of regular sexual activity.
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Caroline Jacoby In Nepal a young woman awaits her marriage ceremony. Women’s age at marriage is one of several important factors that, along with contraceptive use, affect fertility levels directly. |
Among surveyed countries, in North Africa and the Near East the average age at first marriage has risen from below 18 for the oldest women (ages 45 to 49 at the time of survey) to 20.6 for women ages 25 to 29 (see Table I). Less dramatic downward pressures on fertility are apparent in sub-Saharan Africa and Asia, but not in Latin America and the Caribbean, where the median age at first marriage seems to have been steady at almost exactly 20 years for two decades or more.
A rising age at first marriage helps lower the birth rate, especially where there is little control of fertility within marriage. While the precise relationship of age at marriage to fertility is difficult to measure, surveys reveal a strong inverse relationship between the average age at marriage and the TFR in a country.
Not every married woman is at risk of pregnancy, while some unmarried women are at risk of pregnancy because they are sexually active (see chapter 7.1, Sexual Activity). In a study of Nigerian women in 1990, for example, 36% of married women reported that they were not sexually active—over 80% due to postpartum sexual abstinence. At the same time, 38% of unmarried women reported that they were sexually active (26).
Postpartum Insusceptibility
Postpartum insusceptibility to pregnancy includes postpartum amenorrhea, which occurs between the birth of a child and the resumption of ovulation, and postpartum abstinence from sexual intercourse. The length of postpartum amenorrhea depends primarily on the intensity and length of breastfeeding (61, 105).
The period of postpartum insusceptibility is longest by far in sub-Saharan Africa; the median duration averages over 15 months. This long duration reflects mainly postpartum amenorrhea in all but 5 of 28 countries with data. The length of postpartum insusceptibility is much shorter in other regions (see Table J). In all surveyed countries outside sub-Saharan Africa, the period of postpartum amenorrhea is longer than the period of postpartum abstinence.
Worldwide, in 30 countries with data from two surveys since 1990, declines in the duration of postpartum insusceptibility to pregnancy have typically been small (averaging only one-half of one month). The changes have had little effect on fertility levels.
