Number one baby gets new clothes, regular baths and organised outings. But when it comes to numbers two and three, Fiona Gibson throws her good intentions out of the window.

My mother-in-law came to visit last week. She smiled an indulgent granny smile as Erin, our six-month-old daughter, ground a breadstick into the carpet. Then Erin turned and grinned at her grandmother. My mother-in-law’s jaw dropped. ‘The baby’s er…’ ‘Crawling already?’ I butted in, proudly. ‘Yes, she’s coming along so…’ ‘No, not that,’ she said. ‘It’s her face.’

Mother-in-law scrabbled in her handbag, extracted a tissue and licked it. By the time she had finished her deep-cleansing exercise, I hardly recognised my own daughter. It was weird, seeing her cheeks so shiny and with no sweet potato attached. I had forgotten she was pink underneath.

Dirty child: bad mother? Not quite. The purée-smeared child is more likely to be the second (or subsequent) child. We’ve done the baby stuff before. We know that our child will not be snatched by social workers if her nose is not wiped the second it runs. And does she really need a fresh, snow-white bib every mealtime?

First time around, we ensured a steady supply of bibs of dazzling brightness. We felt immense pressure to be perfect. New parents dare not take a child out in public in mismatched socks in case word flies around the NCT group that this mother is ‘not coping well’. A friend admits: ‘When Chloe – now four – started nursery, you had to put your kid in a fashionable and spotlessly clean outfit. It was like some mini fashion parade, and if she splattered herself with paint, poor Chloe would be in tears.’

So would I. Some of those dresses set her mother back £40. But my friend has found rearing her second child (now a grubby-fingernailed two-year-old boy) a very different experience: ‘It’s unrealistic to expect him to stay smart and clean’ she says. ‘Even on the five-minute walk to playgroup, he’s bouncing in and out of hedges and prising a lump of old chewing gum off the pavement. I’ve been forced to relax my standards,’ she admits. ‘It’s a relief, actually, and much cheaper.’

I can identify with this. When the boys were babies I haunted Baby Gap. But Erin is dressed almost entirely in hand-me-downs. When she splatters her T-shirt, I bung another on top, then a cardigan and jumper until, by bath time, she looks like a Michelin baby. Call it neglect if you like. Her fingernails grow a tad too long sometimes, and she is not bathed every day. I don’t chart her progress against age/stage guidelines in a baby manual, and we visit the clinic so rarely the health visitor assumes something horrific has happened when we do put in an appearance.

It’s not that I care for Erin any less than her big brothers. But child number three (or four or five) is required to muck in – literally – with an already lively household. And my daughter seems as happy twiddling her brothers’ Duplo bricks as they used to be, while gazing at the hand-painted seahorse mobiles we’d constructed from papier mâché.

In the past, fellow first-timers and I would huddle in corners at toddler groups and fret that our infants weren’t being stimulated enough. I met one woman whose two-year-old was regularly whisked from painting class to music group to tea with friends (where, no doubt, they would fashion an entire menagerie of home-cooked Play-doh animals). Another mother used to lay out an array of interesting objects to greet her child every time he woke from his nap. No wonder she barely had time to go to the toilet.

So yes, it’s a relief not to strive for perfection. I have opted out of the great parenting race (Whose child will be first to crawl/take steps/recite the Cyrillic alphabet?). And you know what? No one has told me off. I see no wagging finger of disapproval when, at bath time, a varied assortment of crumbs is discovered nestling down the front of Erin’s vest.

Parents often report that second and subsequent children are more easy-going than their first. A result of a slob-mother attitude, or mere coincidence? Perhaps babies simply like being allowed to lick banana porridge from their sleeves. Mind you, with a mother-in-law like mine around, she’ll have to be quick about it.