Even among young married women, many births are unintended. Often the marriage was precipitated by an unintended pregnancy. For example, in Chile 35% of married women ages 15 to 20 reported their first births as unintended, and 42% of those pregnancies were premaritally conceived (204). Surveys in six African countries report that between one-fourth and one-half of first births to married women ages 15 to 19 were unintended (119, 120, 122, 124, 126, 127). Unintended pregnancies are not rare even where early marriage and childbearing are the norm. For example, in Pakistan 34% of current pregnancies among ever-married young women were unintended, as were 24% in Egypt (see Table 6). In India among ever-married young women, 16% of current pregnancies and births in the preceding four years were unintended (583).

A young woman's pregnancy is more likely to be unintended if she is unmarried. For example, in Kenya the percentage of current pregnancies among women ages 15 to 19 reported to the DHS as mistimed or unwanted was 7% among married women and 74% among unmarried women. In Peru 51% of current pregnancies among young married women were unintended compared with 69% among unmarried women. Other Latin American surveys indicate that 44% to 76% of first pregnancies among young unmarried women are unintended (338). Among never-married women ages 15 to 24, 59% in Costa Rica and 65% in Brazil reported their first pregnancies as unintended. In Jamaica 76% of all first pregnancies were unintended. Unintended pregnancies often ends in abortion, even where abortions are unsafe (54) (see Chapter 2.4, Unintended Pregnancy and Complications of Unsafe Abortion).

The majority of young women in the developing world still have their first child within marriage. Therefore median age at first birth still closely follows median age at marriage (519) (see Tables 2 and 5). In developed countries and parts of Asia and the Near East, where most women marry after age 20, fertility rates among women ages 15 to 19 are low. In countries where most women still marry young, fertility rates among women ages 15 to 19 remain high—reaching close to or over 200 per 1,000 women in such places as Mali and Niger (see Table 7).

As age at marriage rose during the late 1970s and 1980s, fertility rates among women under age 20 declined in many countries (298, 441, 490). The decline was especially dramatic in much of Asia (298, 490). Another indicator of declining fertility among young women is a drop in the percentage of women who gave birth before age 20. In most countries except those in sub-Saharan Africa, smaller percentages of women ages 20 to 24 at the time of a recent survey were mothers before age 20 than in previous generations (see Table 2). In nearly all countries rural women and less educated women are the most likely to have a child by age 20 (490, 579). Rural/urban differences are greatest among the younger women in this age group because urban women ages 15 to 17 are less likely to be married and more likely to be attending school than their rural counterparts (370, 490).

Even as overall fertility rates are declining, births to young women increasingly occur outside marriage in many regions (54, 185). For example, an analysis of DHS data for Burundi, Ghana, Kenya, Liberia, Mali, Togo, and Zimbabwe showed that the percentage of women who gave birth before marriage had increased in all seven countries (166). Premarital childbearing was more common among literate than nonliterate women in all these countries except Zimbabwe. This increase appears to result not from earlier sexual activity but rather from later marriage, since literate women in most of these countries began sexual intercourse at later ages than nonliterate women but also delayed marriage. Thus these young women spend more time exposed to the risk of premarital pregnancy and are more likely to give birth before marriage (166).