Introduction:
Adolescent motherhood is associated with a high risk of health problems due to the unfinished process of biological development of the body.

Aim:
To compare the course of labour among adolescent mothers (aged up to 17 years) and young women (aged 18–19 years).

Material and methods:
The study was performed on the basis of a retrospective analysis of medical records from 2010 to 2018 in one of the clinical hospitals in Poland. The analysis included the births given by 133 adolescent mothers and 169 young women.

Results and discussion:
There was a downward trend in the percentage of births given by adolescent mothers and young women over a 9-year period. The placenta of adolescent women was lighter, by 25 g on average (P = 0.011), and had a smaller size (P = 0.038) than the placenta of young women. In adolescent women, pregnancy-related complications were significantly more often associated with pregnancy-induced hypertension (P = 0.037), and in young women with gestational diabetes (P = 0.003). The rapture of membranes was observed significantly more often at the first stage of labour among mothers aged 18–19 years than in mothers aged up to 17 years (P = 0.043).

Conclusions:
A decrease in the number of births given by adolescent mothers and young women over 9 years was demonstrated. Among adolescent mothers a pregnancy-related complication was pregnancy-induced hypertension. The placenta of adolescent mothers was significantly lighter and smaller than of young women. The rapture of membranes (in the first stage of labour) concerned more often women aged 18–19 years.