In theory, the first trimester of pregnancy should be one of the happiest and most exciting times in a woman's life. But for many women it is, to quote Dickens, the best of times and the worst of times.
Pregnancy hormones, nausea, fatigue and the significant threat of miscarriage can conspire to turn this celebratory time into 12 weeks of purgatory.
My own experiences of the first trimester have not been great. The first was spent battling packed rush-hour Tubes and working long days while overwhelmed by nausea 24 hours a day; the second came to an abrupt end with a miscarriage discovered at seven weeks (on our two-year wedding anniversary).
In both instances, it was a time when I craved the support and understanding of those around me but societal pressures told me, for want of a better phrase, to keep mum.
There is a simple explanation for this: it is believed as many as one in five pregnancies end in miscarriage and the majority of these happen in the first trimester.
Miscarriage rates drop dramatically once a healthy heartbeat has been detected at the 12-week scan, so most women prefer to wait until this point, when statistics are on their side, before going public.
For some it's a matter of superstition.
"I just didn't want to tempt fate!" says Sarah, 29, a dental technician. "I knew there was a high risk of miscarriage in the first trimester and I felt that by telling all my friends and work mates I'd be somehow jinxing it."
For others it's a privacy issue.
"I'm generally quite a private person," says Amanda, 37, a press officer for a charity. "And although part of me wanted to shout it from the rooftops, it was the prospect of having to talk about it to anyone, other than immediate family and close friends, if something went wrong."
But there is a flaw in this plan. What if miscarriage - the reason we are so precious about this stage of pregnancy - is the very reason we need to be open. For while it's important to respect privacy when it comes to personal matters, it's equally important to respect the need to talk.
The '12 week' rule implies, whether you're enduring the horrors of severe morning sickness or the heartache of miscarriage, you should suffer in silence.
The implication is that sharing a newly discovered pregnancy – or a lost pregnancy – with anyone outside of your closest support network is 'over sharing' and somehow uncouth.
And the need to be open isn't confined to those who like to wear their hearts on their sleeves. Take those juggling difficult pregnancies with high-pressured jobs, for instance.
"I suffered severe morning sickness," says Sophie, 32, the marketing director of a major blue-chip company.
"On more than one occasion I threw up on the way to work – once in a bin on the street and once on a Tube station platform," she recalls.
"I sat through endless meetings and presentations, smiling through gritted teeth, my face glimmering with sweat, praying I would make it through to the end without vomiting.
"It was like trying to conceal the mother of all hangovers – but every day for months."
Like many women in the same position, Sophie felt she couldn't talk about what she was going through to her colleagues and bosses.
"I work in a male-dominated industry and in my company – particularly at this level of seniority – it is deemed highly inappropriate to bring your personal life into the office.
"I felt that discussing my pregnancy would be viewed as a sign of weakness. I see now that this was largely down to the backward culture I was working in and have since resigned and moved on.
"But I do think the '12 week' rule was also a large part of the problem. I felt there was a lot of pressure to remain tight-lipped as though that were more dignified."
Similarly, the workplace can be a forbidding environment for those dealing with miscarriage.
"My miscarriage was a long drawn out process. I was bleeding heavily for almost three weeks," says Dawn, 34, an account executive at an advertising agency.
"I wanted to come back to work to take my mind off things but it was a miserable and isolating experience sitting at my desk, miscarrying a baby, without anybody knowing.
"In the end, I caved in and told a couple of close work friends. But I didn't feel comfortable telling my boss – a young man with no children – as I felt this shone a light on the fact I was trying for a baby and would therefore give the impression I was less focused on my career."
Dealing with a situation like this can be challenging enough when it's an isolated incident. But imagine the long-term impact the '12 week' rule can have on the thousands of couples battling infertility issues – often dealing with failed fertility treatments and multiple miscarriages over the course of months, even years.
"My husband and I have been through two unsuccessful rounds of IVF treatment and have suffered three miscarriages over the past six years," says Jane, 29, a retail manager.
"Thankfully, we now have a beautiful 12-month-old daughter but over the years our fertility issues have had an impact not just on our work lives but on our friendships, too," she adds.
"Reasonably close friends, who have known about our IVF treatments, have been thrilled for us when the treatment has been successful but have been notable by their absence when things haven't gone according to plan – when we've needed them most."
Jane believes this is a cultural issue rather than an individual lack of empathy.
"I think the problem is that with so many people keeping their pregnancy a closely-guarded secret until the hallowed 12-week scan, people don't know whether they're 'allowed' to ask before that point."
While I have every respect for those women who would prefer to keep their pregnancies private, for the sake of those facing difficulties during those early weeks – whether it's challenging side effects, a miscarriage or ongoing fertility issues – it's about time we lifted the lid on this 'secret' trimester.