Wanna check if any mummy get pregnant while breaatfeeding and no menses yet . Is it harder?

Supposedly harder to get pregnant while breastfeeding and having no menses yet but there is no guarantee. According to studies, breastfeeding delays ovulation. So in order for breastfeeding to act as a contraceptive, you should be breastfeeding on demand, menses have not returned and baby younger than 6 months. Tips for delaying ovulation include: -nursing on demand -baby does not sleep through the night -baby should latch all the time -delay weaning until 6 months So I have met ALL the above 4 requirements and I got my period at barely 4 months post partum.