If you are experiencing leaks at the leg, this is usually due to poor fit of the nappy. Ensure you tuck the leg elastics into the knickerline.
If the inserts are saturated, then you need more absorbency; bamboo and hemp are excellent for this. Please note that you should expect to change a day nappy every 2-4 hours (and sometimes more frequently with a newborn).
Leaks when using the car seat, sling or buggy are usually due to compression. Avoid microfibre, and stick to bamboo, hemp, or a fitted nappy and wrap for these situations.
Using liquid detergent or certain nappy creams can coat fibres in nappies, leading to leaks over time. In this case, a strip wash is needed.