Introduction: The purpose of our study was to investigate the factors that favour teenage pregnancy. This was a case-control study of adolescent girls aged 13 to 19 who were sexually active. It was conducted over a period of 5 months in the Gynecology and Obstetrics Department of the Yaounde Gynaeco-Obstetrics and Pediatric Hospital (YGOPH) and Yaoundé Central Hospital (YCH). We compared teenage girls seen at prenatal consultations (cases) to those coming for gynecological consultations (controls). The variables analyzed were sociodemographic data, risk behaviours, family data, data related to education and sexuality, and contraception. Data analysis was done using the Epi Info software version 3.5.4 and SPSS version 20.

Results: We recruited 170 teenage girls, 85 cases and 85 controls. Predictors of pregnancy occurrence among adolescents found in univariate analysis were: co-habitation (OR = 4), in a semi-urban setting (OR = 2.2), with her husband / fiance ( OR = 3.02), having only one sexual partner (OR = 15.16), having sisters (OR = 3.3), having a mother who conceived in adolescence (OR = 2.05), having her first sexual intercourse before age 16 (OR = 2.2), knowing family planning (OR = 2.98) and considering FP counseling as useless (OR = 3.3), not discussing sexuality with peers (OR = 2.27), does not search for information about sexuality in magazines / newspapers (OR = 4.7) or on the internet (OR = 5.4), does not know about abstinence (OR = 2.2) , coitus interruptus (OR = 8.2) or the morning-after pill (OR = 5.18).

Conclusion: The independent predictors of teenage pregnancy in our setting were premarital sex before age 16 and non-use of contraceptive methods.