This is a randomised trial of two modern single electric breast pumps allocated to mothers who are exclusively breast feeding their healthy term infants. Mothers will be recruited when their infants are around a month old, they will be randomised either to use one of two state of the art modern single electric breast pumps or to act as controls with no breast pump (but will receive a baby care voucher of similar value). If allocated to a breast pump, mothers will be asked to take part in a physiological study when their babies are 6 weeks old. In this test the mothers will be asked to express breast milk for 10 minutes on each breast. The primary hypothesis is that the total weight of milk produced in a 20 minute period and the weight of milk produced at 1 minute intervals at age 6 weeks will be greater for mothers using one of the pumps. A small sample of breast milk (~5ml) will be collected for analysis, the remaining expressed milk will returned to the mother.

Each month between the age of 3 and 6 months, all the mothers will be asked to complete online questionnaires about their breast-feeding and the use of their breast pumps (if they have one). At the end of the six months the mothers will be given a small voucher for a child-care store as a way of saying 'thank-you' for the inconvenience caused.

Inclusion Criteria:

Mothers who have delivered healthy, term, singleton infants with no contra-indications for successful breast feeding.

Mothers who are exclusively breast feeding and are willing to be randomised to either use a breast pump or to continue breastfeeding without using a breast pump.

Not already using a breast pump. Can speak, read and write in English (or Chinese for Beijing centre or Russian for Moscow centre)

Exclusion Criteria:

Mothers are ineligible to join the study:

If they are mixed or formula feeding. Have an illness that may prevent them from expressing breast milk. Are not willing to be randomly assigned to the pump or the control group Already expressing milk regularly.

-