Having a baby, whether by accident or design, impacts on your life and work like nothing else. Without children it is easy to sustain the fantasy that you are invincible, that hard graft and commitment will always be rewarded with success, that other women who fall by the wayside simply don't have what it takes.
But pregnancy brings you down to earth with a bump, and you realise that the eternal truths of work and motherhood apply as much to you as anyone. Employers instantly register you as a diminishing return rather than an asset; male colleagues pat your tummy and tell you how you will feel different about coming back once it has arrived - never mind the mortgage and your penniless partner. It can all end very messily, as in the case of Sara Mitchell, who claimed recently that her high-flying business career was stymied when her boss suggested she abort her baby to save her job.
So is there ever a good time to have a baby without wreaking havoc on your promotion prospects? According to Lucy Daniels, corporate affairs adviser at WFD, a consultancy which advises employers on how to help their staff balance home and work commitments, motherhood is best embarked upon either when you are starting out or when you have reached a senior position. Having a child when you are young will not do as much damage as it might a few years on, while waiting means you are likely to have more money and autonomy.
"The very worst time in a career to have a baby is when you have little control over your time and you're at the beck and call of your manager," she says, citing the example of a woman who had four children after becoming a partner in her law firm. "At that stage she could delegate more and had greater control over how her time was spent. She was past having to prove herself by working lots of extra hours, and had the income to back her up."
But author and broadcaster Rosalind Miles believes early motherhood is your best bet. Having met her husband during her first week at university, she married and had her first child at 21. "The downside was that I was very young and inexperienced. I was an articulate graduate when I had my baby, but it didn't help when I was naked to the waist with my feet in stirrups. The consultant sweeps in with 17 students and says `Don't worry, Mrs Miles, we're not embarrassed.' Now I would have just told them to get lost."
But Miles believes first-time motherhood is the pits no matter how old you are. "People make the mistake of trying to slot a baby into their lives, but it does and should change things. It's much easier when you're younger, and your life and career are more flexible."
The trouble with waiting until you are a hard-hitting barrister or chief executive officer is that your life is highly organised and you are accustomed to having your own way, she believes; having a baby throws a very unpredictable element into the works. "When you're older a baby's life impinges far more on yours, and there is nothing more excruciating than a collision between your duty to your employer and your love for your child." Not to mention your lesser physical strength.
"Motherhood is the most physically exhausting thing there is," she says, "Even in my twenties, I would still pass out at dinner parties from sheer fatigue."
Waiting for the right time to have a baby may be entirely fruitless anyway, believes Rachel, an accountant who finally had a son when she was 38. "I had a pregnancy scare when I was 25 and sat in the clinic saying `I can't be pregnant', over and over again. When the nurse asked why, I said it wasn't the right time. She just looked at me and said it's never the right time."
Sixteen years on Rachel agrees. Joining her firm at 32, she worried that a baby would spoil her plans - she wanted to see how far she could get. It was not until her new boss arrived that she decided her career was not going anywhere and threw away her cap. But by then it was too late, and Rachel had to undergo IVF to conceive. "I should have taken this biological clock stuff more seriously; I didn't believe you went off the boil as quickly as you do."
While Rachel can see that it might have been better to cut her losses and move on, sticking it out at her firm and having a baby later in life at least enabled her to achieve a measure of success and security. "If I'd had a baby during my two-year stint as a secretary after university, I'd probably still be typing letters now. Anyway, a late baby is an immense face-saver if your career has ground to a halt or you're hitting your head against the glass ceiling. You don't have to feel ashamed you're not still climbing up that ladder."
Ultimately it is impossible to predict where motherhood will lead; what looks like a disaster at the time can turn out to be a blessing five years on. My boss's prehistoric attitude towards working mothers finally propelled me into freelancing with a fat redundancy cheque in my pocket, and I've never looked back. Daniels, too, found that her baby provided a catalyst for change from a high-powered, but exhausting, job in marketing.
"I was one of those women who said that having a baby wouldn't change me, back in the office two weeks after the birth with the baby sleeping on the boardroom table while I worked." But after her second, she felt compelled to give it up. "It was a choice of working like a slave to pay for a full-time nanny and never seeing the children, or stopping altogether. I really regretted it, I felt I'd never get such an interesting job again."
After attending a course on setting up your own business, however, Daniels became so angry about the lack of support for women returning to work that she helped establish a national support group, Parents at Work, which eventually led to her job at WFD.
"Babies are seen as a negative thing, and indeed they can bring problems with the workplace to a head - but this can act as a spur for a complete change of direction, and what is seen as a sad ending is often a wonderful new beginning. I've carved myself an exciting new career, but ultimately I owe it all to my kids"n
Lessening the impact
Choose a company offering family-friendly policies. Employers are waking up to the fact that women will vote with their feet if they do not feel they will be treated equably.
Talk to other women about their experiences. Companies which sound wonderful may only pay lip service to equal opportunities. Good policies are one thing, but employers must ensure that managers and bosses do not make life difficult for mothers.
Be strategic. Do your homework on your employment rights and company policies. Think through all the implications for yourself and your job before suggesting something like a job share. Work out ways you can sell the benefits to your boss.
Don't do yourself down. Try not to be browbeaten by managers who denigrate your skills and experience. Hold your head high and insist you are a valuable asset.