Many experts still cannot agree on the definitive answer to this “when a postnatal Mum can or should run” as all human beings are different and all births are different. Mum activity, including running, has grown in popularity in the last 15 years, however most logged research has been based on elite athletes, (Paula Radcliffe and team mates) not a ‘general Mum’ running a slow 100m stretch in a BuggyFit class, or for 30 minutes around a park on a Saturday morning..
If you are keen to get back to running, the key considerations for any postnatal woman are stabilisation and rehabilitation. New Mums need to regain full joint and pelvic stability, realign muscular rebalance, altered biomechanics, and heavy breasts and there could be a change in gait/foot strike. Your precious cargo is something to consider if you wish to run with a buggy too.