"Need", in this context, has its usual meaning. The key here is the use of "seem". This makes it Deirdre's opinion about the woman's state of mind (what she needs) and not a statement of fact. For example:
Hello, can I help you? You seem to be lost.
I don't know if the person is actually lost, but that seems to be my perception of their state of mind. I could alternately ask:
Hello, are you lost? You seem to need a guide.
Again, I don't know if they think they need a guide. That's just my interpretation of the situation.
In the same way Deirde is interpreting the woman's personality, particularly her desires and motivations, while at the same time offering useful advice.
Because the sentence includes "seem", there's no way this would be interpreted as a recommendation. If Deirde meant to give her advice, she would have written it differently:
You need to ask yourself if you're ready to be a mum.
Side note: Be aware that Deirdre Sanders is apparently not a licensed therapist or professional counselor. Moreover The Sun is well known as a tabloid newspaper, meaning that it tends to focus on the sensational and provocative, and many of its stories may not be entirely true. People do seem to find her advice useful and entertaining, as she's been doing this for over 30 years, but her editors seem to deliberately select letters by their lurid subject matter, more than their general applicability.
Which is to say, don't take anything written in this column (or, indeed, the entire publication) too seriously.