According to medical research there is a direct link between the baby crying for the mother milk , for the baby’ s survival and in turn when a mother breast feeds the baby acts a natural contraceptive and prevents pregnancy. Breastfeeding acts as a natural contraceptive during the first six months after birth, stopping women from menstruating. According to Professor David Haig, of Harvard University who explains the  babies’ instinctive urge to keep their mums awake, breastfeeding at all hours, is  a natural way of contraception and the baby’s survival instincts.

He said that the time of life when babies are most likely to wake often in the night, around six months, corresponded to the time when mothers were most likely to be becoming fertile again. The research was published in the Journal Evolution, Medicine and Public Health today.