Adolescent pregnancy is pregnancy in girls age 19 or younger.

The rate of adolescent pregnancy has steadily declined since reaching an all-time high in 1990, mostly due to the increased use of condoms.

Since no form of contraception is completely effective, abstinence (not having sexual intercourse) is the only sure way to prevent pregnancy. A sexually active teenager who does not use contraception has a 90% chance of becoming pregnant within a year.

Why teenagers have sex, and do so without effective methods of contraception, is a topic of debate. Suggested reasons include:

• Adolescents become sexually mature (and fertile) approximately 4-5 years before they reach emotional maturity.
• Adolescents today are growing up in a culture in which peers, TV and movies, music, and magazines transmit subtle and obvious messages that unmarried sexual relationships (specifically those involving teenagers) are common, accepted, and even expected.
• Education about responsible sexual behavior and specific, clear information about the consequences of sexual intercourse (including pregnancy, sexually transmitted diseases, and psychosocial effects) are frequently not offered. Therefore, much of the "sex education" that adolescents receive filters through misinformed or uninformed peers.

When compared with other industrialized nations, the United States has the highest rates of pregnancy, abortion, and childbirth among teenagers, despite similar or higher rates of sexual activity in the other countries.

Teens are more likely to become pregnant if they:

• Begin dating early (dating at age 12 is associated with a 91% chance of being sexually involved before age 19, and dating at age 13 is associated with a 56% probability of sexual involvement during adolescence)
• Drop out of school
• Grow up in poverty
• Have a mother who was 19 or younger when she first gave birth
• Have been a victim of sexual abuse or assault
• Have no support system or few friends
• Lack involvement in school, family, or community activities
• Live in a community or attend a school where early childbearing is common and viewed as normal rather than as a cause for concern
• Think they have little or no opportunity for success
• Use alcohol and/or other drugs, including tobacco products

Pregnancy symptoms include:

• Abdominal distention
• Breast enlargement and breast tenderness
• Fatigue
• Light-headedness or actual fainting
• Missed period
• Nausea/vomiting

The adolescent may or may not admit to being involved sexually. If the teen is pregnant, there are usually weight changes (usually a gain, but there may be a loss if nausea and vomiting are significant). Examination may show increased abdominal girth, and the health care provider may be able to feel the fundus (the top of the enlarged uterus).

Pelvic examination may reveal bluish or purple coloration of vaginal walls, bluish or purple coloration and softening of the cervix, and softening and enlargement of the uterus.

• A pregnancy test of urine and/or serum HCG are usually positive.
• A pregnancy ultrasound may be done to confirm or check accurate dates for pregnancy.