title: The association between sequences of sexual initiation and the likelihood of teenage pregnancy.
abstract: OBJECTIVE
  Few studies have examined the health and developmental consequences, including unintended pregnancy, of different sexual behavior initiation sequences. Some work suggests that engaging in oral-genital sex first may slow the transition to coital activity and lead to more consistent contraception among adolescents.
  
  
  METHODS
  Using logistic regression analysis, we investigated the association between sequences of sexual initiation (i.e., initiating oral-genital or vaginal sex first based on reported age of first experience) and the likelihood of subsequent teenage pregnancy among 6,069 female respondents who reported vaginal sex before age 20 years and participated in waves I and IV of the National Longitudinal Study of Adolescent Health.
  
  
  RESULTS
  Among female respondents initiating vaginal sex first, 31.4% reported a teen pregnancy. Among female respondents initiating two behaviors at the same age, 20.5% reported a teen pregnancy. Among female respondents initiating oral-genital sex first, 7.9% reported a teen pregnancy. In multivariate models, initiating oral-genital sex first, with a delay of at least 1 year to vaginal sex, and initiating two behaviors within the same year were each associated with a lower likelihood of adolescent pregnancy relative to teens who initiated vaginal sex first (odds ratio = .23, 95% confidence interval: .15-.37; and odds ratio = .78, 95% confidence interval: .60-.92, respectively).
  
  
  CONCLUSIONS
  How adolescents begin their sexual lives may be differentially related to positive and negative health outcomes. To develop effective pregnancy prevention efforts for teens and ensure programs are relevant to youths' needs, it is important to consider multiple facets of sexual initiation and their implications for adolescent sexual health and fertility.
authors: Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27516-2524, USA. bmreese@live.unc.edu
authors: Bianka M
authors: BM
authors: Reese
authors: Abigail A
authors: AA
authors: Haydon
authors: Amy H
authors: AH
authors: Herring
authors: Carolyn T
authors: CT
authors: Halpern
mesh_terms: D000293:Adolescent; D005260:Female; D006801:Humans; D016015:Logistic Models; D015999:Multivariate Analysis; D011247:Pregnancy; D011253:Pregnancy in Adolescence; D011446:Prospective Studies; D012307:Risk Factors; D012725:Sexual Behavior; D014481:United States