Re: enter into vs enter
A market where you go to shop is an actual physical thing which you would simply enter. You enter a building which houses a lot of different market stalls. The area/building is called a market.
When you are talking about "a new and undeveloped market", you are talking about a group of potential buyers or investors (in this case, the parents of newborn babies), then it is not a physical market so you would enter into that market.
Remember - correct capitalisation, punctuation and spacing make posts much easier to read.