Final answer:
Lactating does not fully prevent pregnancy, and ovulation can occur even without menses, making it a true statement that breastfeeding is not a foolproof contraceptive method.
Step-by-step explanation:
Lactating does not prevent pregnancy, even if menses has not yet resumed is a true statement. While breastfeeding can have some contraceptive effects, known as the amenorrheic effect, it is not fully reliable for preventing pregnancy. Ovulation can occur even before the return of menstruation, which means a woman can become pregnant. Therefore, relying solely on lactation as a method of contraception can lead to unintended pregnancies.