In its report Born Equal?, published today, the observatory concluded there is 'room for improvement' in every PCT in London.
It shows that babies most at risk are born to mothers living in the most deprived parts of the capital. The highest infant mortality rates are in Haringey and Hackney. The lowest are in outer and west London, it says.
LHO director Dr Bobbie Jacobson said: 'The burden of infant deaths is concentrated in poorer households in east and north London double the rate of well-heeled areas.'
She said it was important to ensure all women, particularly from at-risk groups, were able to benefit from early access to maternity care.
'To target care and track progress effectively we need good-quality maternity data, and this has not been available across the board. We would like to see a big improvement in data collection from all acute trusts in the future,' Dr Jacobson added.
The report calls for renewed emphasis on some short-term goals to reduce inequalities in infant death in the capital. These include stop-smoking programmes in early pregnancy, initiation and maintenance of breast feeding and 'high quality, culturally appropriate antenatal care' that is accessible as early as possible.