Sexual behaviour and early coitarche in a national sample of 17 year old Swedish girls

Objective: To evaluate sexual behaviour in 17 year old girls, using data from a national survey on adolescent sexuality. Method: The study was based on two samples of 17 year olds, comprising 2% of the population born in 1973 and carried out in 1990. A school sample and a sample of school non-attenders were recruited in a two step procedure. Data were collected by anonymous self administered questionnaires. 2583 questionnaires were distributed. Response rates from students was 92%, fur school non-attenders 44%. 1121 female students and 118 female school dropouts responded. Results: 64% of the student girls had experienced their first intercourse; 16% were "early starters" with coitarche before age 15. STD and pregnancy were reported by 15% of early starters and pregnancy by 14%, p<0.001 and 0.002 respectively when compared with later starters. The number of coital partners, experience of first date intercourse, and of oral and anal sex was higher in the early starters, p<0.001. Early starters reported menarche at age 11 or earlier more often than the later starters (OR 2.30, 95% CI 1.48-3.56), as well as a perceived social age exceeding the chronological by 2 years (OR 1.94, 95% CI 1.34-2.80). Sexual abuse was reported by 20% of the early and 11% of the later starters, p=0.002. Among school non-attenders no significant differences were found with regard to age for coitarche. A majority of 83% of the girls had experienced voluntary intercourse, and 49% were early starters. Five girls were mothers. STD was reported by 19% and induced abortion by 14%. Sexual abuse was alleged by 28%. Conclusion: Coitarche before age 15 is related to early menarche and high perceived social age. High number of partners and first date intercourse make early starters at increased risk for STD and unintended pregnancy. Sexual abuse is alleged more often by early starters.