Here I am on my 29th birthday, 5 months pregnant with my first and looking for new, non alcoholic ways to celebrate.  We hired a boat on the Thames and picnicked.  You might spot the Jo Jo Bebe Maman bag, the birthday presents have shifted slightly, to mark my mum-to-be status

I think it is fair to say I was an early adopter to pregnancy amongst my closest friends.  Shortly after this my husband and I decided to leave behind our life and friends in London to set up business and home in Nottingham.  I decided to leave teaching and to be a full time mum for a few years. Looking back it was a pretty huge transition.  I approached it alot like freshers week at university and joined as many antenatal or baby related groups as I could.  I soon made lots of wonderful new mum friends, many of which I see on a weekly basis 5 years on.

But what about my friends of old,my school friends, the gang of girls I went to university with and then gravitated to London with?  I missed them hugely, I didn't see them as often and sometimes, especially when I had to say no to things, because I was still breastfeeding, because I didn't feel ready to leave my babies or because I was tired or strapped for cash, I felt our lives had moved in different ways. But, despite missing a few birthdays, not keeping up on gossip and feeling a little like I was missing out on their child free fun, we are still going strong.

One bonus of friends who don't have children is they have a different perspective to mum friends. I was concerned about boring my old friends about my babies, but in actual fact I couldn't answer their questions about pregnancy, birth and babies fast enough.  They were genuinely fascinated and made me feel proud of the huge learning curve I had been on. They weren't juggling their own children so gave generous amounts of time to mine. They would come and visit for a weekend, cook lovely food, play with my children, then take me out.  It was this distraction from the world of babies that was so important, it reminded me of the hopes, dreams, passions and ideals that make me who I am.  They have been incredibly perceptive about how Penny as a person translates into Penny as a mother, and whenever I have felt I am losing the balance of self and motherhood, they have helped me regain it. As time went on I made friends locally who don't have children, or children the same age, but share some of my interests beyond children: theatre, writing, creativity, self employment. It was important to nurture those sides of me, as well as supporting me as a mother.

My friends who don't have children often have more time, which means they organise the most fantastic events which I am permitted to simply pay for, and turn up to. Camping trips, weekends in cottages with hot tubs, festivals, pampering evenings, amazing creative events.  Although, after my second child I was so desperate to be part of our annual May bank holiday camping trip, I organised a tipi in our back garden.  This meant I could still breastfeed, my friends could see my children, but my husband could also whisk them off, so I still had a whole weekend with the girls. It was a little thank you for being there for me, but I know I owe them a few more visits to London now the babies are so much bigger.

Now my friends are beginning to have babies, and I'm realising one downside of having babies earlier was I missed out on the baby shower trend, (although I lasted all of about 2 mins with a sympathy balloon up my jumper at my friend's shower). I can see I am probably going to need to step in as social secretary at some point, and be as patient with them as they were with me, as they navigate the new territory that is parenthood. What goes around comes around. And I better start remembering every detail of my pregnancy, birth and newborn days, because they want to know how it's done. I used to quiz my sister in law about newborns as she ran after her 18 month old, and I couldn't believe she couldn't remember.  But it's true, each new stage takes some of the memories of the previous stage.  Having two sisters in law has led to two new and exciting friendships too, and having children has definitely been a big part of our bond.

20% of women don't have children, so I also know I will have friends with whom I won't share parenthood in common, and friendships where we will always look at each others lives and ponder the what ifs of having and not having children.  These people's lives are so full and rich, their facebook timelines full of world events, travel, intellect and stimulation instead of baby milestones and photos. I love how my friends without children help keep me up to date with a much bigger world out there and how willing they are to share it with my children when they visit too.

And my mum friends? Just the most supportive network who will come round with casseroles in a crisis, provide tea and sympathy and whip up a childcare rota to enable everyone to do their Christmas shopping in peace.  They are a constant source of fun things to do with kids, a hand me down chain and a walking encyclopaedia of parenting wisdom. Over the years, we've found common ground as women as well as mothers.

Have you noticed your friendships changing through pregnancy, birth and parenthood?