following the menarche (first menstrual period), which normally occurs between age 11 to 12. After menarche, sexual intercourse (especially without contraception) can lead to pregnancy. The pregnant teenager may then miscarry, have an abortion, or carry the child to full term. Pregnant teenagers face many of the same issues of childbirth as women in their 20s and 30s. However, there are additional medical concerns for younger mothers, particularly those under 15 and those living in developing countries. For example, obstetric fistula is a particular issue for very young mothers in poorer regions. For mothers between 15 and 19, risks are associated more with socioeconomic factors than with the biological effects of age. However, research has shown that the risk of low birth weight is connected to the biological age itself, as it was observed in teen births even after controlling for other risk factors (such as utilisation of antenatal care etc.). Worldwide, rates of teenage births range widely. For example, sub-Saharan Africa has a high proportion of teenage mothers whereas industrialized Asian countries such as South Korea and Japan have very low rates. Teenage pregnancy in developed countries is usually outside of marriage, and carries a social stigma; teenage mothers and their children in developed countries show lower educational levels, higher rates of poverty, and other poorer "life outcomes" compared with older mothers and their children. In the developing world, teenage pregnancy is usually within marriage and does not carry such a stigma. Legal issues Sexual conduct between adults/adolescents and adolescents younger than the local age of consent is generally illegal, aside from close-in-age exemptions or in jurisdictions where only sex between married couples is legal, such as those in some Islamic countries. In many jurisdictions, sexual intercourse between adolescents with a close age difference is not prohibited. Around the world, the average age-of-consent is 16, but this varies from being age 13 in Sudan, age 16 in Spain and Canada, and age 16–18 in the United States. In some jurisdictions, the age-of-consent for homosexual acts may be different from that for heterosexual acts. The age-of-consent in a particular jurisdiction is typically the same as the age of majority or several years younger. The age at which one can legally marry is also sometimes different from the legal age-of-consent. Sexual relations with a person under the age-of-consent are generally a criminal offense in the jurisdiction in which the act was