Having a baby is supposed to be one of the most exciting and joyful experiences you'll ever have.

But often the reality feels quite different. Immediately after birth a woman's body may feel as if it's run a marathon, particularly if she has had a C-section or a long labour.

Furthermore, it seems everyone feels that it is their right to give their own bit of advice, as she and her partner learn to care for their new baby, who doesn't know night from day.

When the partner returns to work it is mum who is generally on call all the time, perhaps with little or no support and often missing the companionship of friends at work.

There may even be a growing sense of anti-climax, fuelled by lack of sleep ? sounds great doesn't it?

Little wonder, therefore that for many women the first few days, weeks and maybe even months of new motherhood can be a time of emotional high and lows.

After the birth of a baby, about half of all mothers suffer a period of mild depression commonly called the baby blues. Typically they start on the third or fourth days after birth and last for hours or at most a few days and then disappear.

The blues are characterised by the mother feeling very emotional and upset, crying for no particular reason, feeling very anxious and tense, tired and lethargic.

It seems that the blues may have several causes, some biological and some emotional.

When a baby is born there are very sudden changes in the mother's hormone levels. Some hormones required only during pregnancy, drop suddenly, while others like those which start the production of milk, rise ? these rapid changes may act to trigger the blues.

Many mothers are unprepared for the extreme weariness which often follows a birth.

It is made up of a combination of factors: apprehension about the birth, physical exertion of the birth itself, constant care of the baby, feeding difficulties and so on.

Generally the blues don't need any treatment, just plenty of loving support and understanding until is passes.

Having someone to listen to your anxieties and to reassure you that what you are experiencing is normal and will not last forever is helpful. Rest is important too.

If the symptoms of the blues go on for more than a few days then postnatal depression (PND) might be an issue.

PND affects about 10 percent of mothers who have recently given birth. Although, interestingly sometimes it does not exhibit itself until months after the birth, when you might least expect it.

I personally suspect that many women have a low level of PND but don't know it ? thinking that what they are feeling is 'normal' ? and it is only recognised as depression in retrospect.

In fact, one of the difficulties of diagnosing PND is that many of its symptoms may be considered 'normal' for a woman trying to get the hang of new motherhood with all its up and downs, exhilarations and frustrations.

Postnatal depression is more likely to affect women who:

Have been having relationship problems before their baby was born.

Had a very stimulating job and find it hard to adjust to motherhood.

May be experiencing rekindled grief from a previous loss or bereavement.

Experienced a difficult birth.

Have previously suffered from depression.

Are extremely tired because their baby sleeps badly or is extra demanding.

Have other difficulties or problems and not enough support.

Most women who have the illness find that they are less able to cope with the demands of the baby and the home.

But once again it is worth remembering that even for women without PND there will be days when they feel overwhelmed and exhausted. Some mothers feel very sad and cry frequently.

Some are anxious and fearful, they worry about their own health and that of the baby.

They may suffer from panic attacks and feel tense and irritable all the time. Most depressed mothers feel tired and lack energy, they may have problems sleeping and often feel unable to concentrate and they find even simple tasks are confusing and demand too much energy.

But as I said before, those can also be occasional characteristics of a woman struggling with new motherhood (or old motherhood!). Often mothers who have this illness feel guilty that they are not 'coping' as well as they should be and will soldier on in silence for fear of being labelled a bad or inadequate mother.

Here is an excerpt from Babyshock by Elizabeth Martyn, written by a mother who herself experienced PND:

"To start with I put my feelings down to tiredness. Finlay was a fretful baby right from the birth and I often felt that I wasn't coping very well. As time went by, I realised I was feeling worse rather than better. Although Finlay was becoming more settled, I still had this terrible churning feeling inside all the time, and had spells where everything seemed totally bleak.

"The crunch came when he was about four months old. My husband came home one evening. Finlay was crying, and I shoved him into my husband's arms and ran down to the end of the garden. I remember screaming and crying 'Take him away, take him away'.

"When I'd calmed down I knew that this was a crisis ? I had to get help, and I saw my doctor the next day."

So it is really important that the depression is recognised (often it is those that are close to the women who notice what is happening) and help sought, not least because it can interfere with the growing relationship between mother and baby.

As with the blues, hormone changes and tiredness caused by lack of sleep can play a part in the depression, as do feelings of isolation. For this reason, sometimes just being listened to is enough, what some might call 'talking treatments'.

This can be with a professional but a good friend might also be able to provide the safe, secure, non-judgmental environment that a depressed woman needs to talk through her feelings.

It can also be helpful to get the right sort of practical support so that the overwhelming feelings of being sole caregiver and homemaker are diminished as the mother is able to rely on others to take on the demands of the house and baby.

Getting out for some personal time and exercise can also be beneficial, as is having adequate rest. These simple but essential things can make all the difference and slowly the mother may notice that the bad days get fewer and the good days more numerous.

Another excerpt from the same book but a different woman: "The big change for me came when I told Matt that I thought I was suffering from depression and needed help. He'd been worried, but hadn't known what to do.

"We saw our doctor together and just acknowledging that there was a problem and having it taken seriously helped me enormously. My doctor referred me to a psychiatrist who visited me twice at home.

"I poured out everything to her and it was as if a weight lifted off me as I talked. In between her first and second visit, I knew that the depression was receding, and after a couple more weeks the bad days had stopped altogether."

Sometimes, however, these self-help measures don't work and anti-depressants may be needed for a period of time.

If correctly prescribed these medicines are not addictive, are safe if the mother is breastfeeding and most importantly, do not mean that she is mad. They are simply another way of getting her back on her feet so she can enjoy her baby and being a mother.

It may surprise you to know that up to a quarter of dads get PND too.

The life changes that go with new parenthood, obviously don't just affect the mother and most men need time to work out their place and role in the new family.

If a man feels he's falling apart, he's just as likely to suffer depression but they often show it differently. He may be irritable, anxious or sleep badly, but he may equally drink too much, be aggressive or antisocial, or take on more work ? staying on longer at the office ? to mask empty, disconnected feelings.

Many couples who have been through an episode of PND are fearful of experiencing another if they go on to have more children. There is no accurate research available on the real likelihood of recurrence. Some women/men do and some don't.

Professional support organisations advise women to make plans in case they do become depressed again and to arrange for plenty of support to be available when they are most likely to need it. Being alert for symptoms and getting treatment swiftly will help to make any depression that does occur last for a shorter period.

It is so important to remember that depression after childbirth is surprisingly common and its diagnosis does not reflect badly on the sufferer in anyway.

In our present maternal climate, where it is important to so many to be able to 'have it all' and always to be seen to be coping, it is often hard for women to admit that they are not.

So if you see a friend struggling or your partner is having a hard time, try and address the topic sensitively. There is help available ? no one should have to fight their way through each day. Remember, the sooner help is sought, the sooner recovery can begin.