A 13-year-old girl is highly fertile. Women are at their peak fertility between ages 13 and 30.
Peak Fertility in Teenagers
Nicole Noyes highlights that the odds of conceiving within a year are significantly higher for teenagers compared to older women. She states, "The odds of conceiving in a given year are about 75% at age 30—but if you're a teenager, it's 90%." [Source: Numerous articles cited including those from Northwell Health and others referencing this statistic] This indicates a much greater chance of pregnancy for a 13-year-old girl with unprotected sex.
Menstruation and Fertility
Menstruation typically begins between the ages of 9 and 13, signifying the start of a woman's reproductive years. [Source: BBC Article on Fertility Changes with Age] Once menstruation begins, ovulation (release of an egg) can occur, making pregnancy possible.
Important Note: Risks
While a 13-year-old is capable of becoming pregnant, it is crucial to remember that teenage pregnancy carries increased health risks for both the mother and child. Studies show that the youngest girls who get pregnant have the highest risk of poor outcomes. [Source: University of Maryland Medical School News on Teenage Pregnancy Risks]
Conclusion
A 13-year-old girl possesses high fertility. This does not negate the risks associated with teenage pregnancy.