It is true that breastfeeding is considered the best supression of ovulation due to the increase in prolactin level. However, as lactation is reduced, the prolactin level returns to its normal state. This is not immediate and, therefore, if pregnancy is not desired, contraceptive protection is recommended.
In addition, we should not forget that, although it is rare, there may be female periods in which there is ovulation but no menstruation.
Therefore, even without menstruation, there is a possibility of pregnancy after childbirth, although it is low.
Read the full article on: Menstrual periods after childbirth – when will they start again? ( 80).
Read the full article on: Ovulation after pregnancy and childbirth: when will it happen? ( 29).
Bachelor's Degree in Biotechnology from the Polytechnic University of Valencia. Master's Degree in Biotechnology of Human Assisted Reproduction from the University of Valencia along with the Valencian Infertility Institute (IVI). Postgraduate course in Medical Genetics.