Pregnancy has a big effect on a woman's body. Some things might surprise you.
It's a good idea to be informed about what to expect so that you can be supportive and understanding of what she's going through.
Here's ten changes you might notice in your partner's body over the nine months of her pregnancy.
1. She could get hairier
Body hair isn't your average conversation topic, so it's no wonder most dads-to-be are shocked when their partner's body begins to change in unexpected ways.
Even the most open-minded men might show surprise at this, but be careful not to criticise. Many women are sensitive about their changing appearance, and the last thing they need is you making werewolf jokes.
The best solution to all body changes is to enjoy them, and love them as much as possible. And if they really bother you, remember they're temporary and for a good cause.
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2. She might lose hair
After the birth, some women lose hair. There isn't usually one spot where hair vanishes, but there can be an overall loss of hair. You might find her body and head hair becomes thinner. As ever, you should be tactful, and remember that it will grow back.
"In preparation for providing milk you may find that your partner's breasts leak during the last two thirds of pregnancy."
3. She might become short-sighted
A woman's body doesn't just make room for a baby. It changes from the cellular level upward, with the major change being a shift in hormones.
This can cause a variety of eye problems during pregnancy. Any change usually resolves itself after birth, when the hormones settle down.
Although some problems can be expected, you should also be aware that vision impairment could be a sign of diabetes and high blood pressure, so don't become too complacent.
4. Only one in 10 women begin labour with their 'waters' breaking
When the uterine sack breaks, don't hold your breath.
We've all seen films where a woman's waters break, and before you know it the baby is sliding out with a few wheezy pushes.
In the real world, it isn't such a momentous event. Sometimes it doesn't break until labour is well established, or it could break hours before labour is fully established.
5. Her breasts may leak
Most men look forward to seeing their wife with larger breasts during pregnancy. Even if you prefer the more petite look, the change can be interesting.
In preparation for providing milk, however, you may find that your partner's breasts leak during the last two thirds of pregnancy.
For some women this is nothing more than an occasional, T-shirt-spoiling dribble. For others, it's constant dripping.
Try not to pull your face or look disgusted. Imagine if your body was changing in such dramatic ways, and be interested rather than horrified.
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6. She might dislike her self-image.
If all goes well, you'll love her changing body, and be enthralled with every new curve and bump.
She might not be quite as pleased. It's easy for women to feel bad about stretch marks, fat and a general feeling of being pumped up. Even the most positive women might feel like this from time to time.
Tell her that she's beautiful. Your words might appear to be falling on deaf ears, but they make a difference.
7. Nine months can feel like a lifetime
It doesn't sound like much time to save up money, or paint the nursery, but nine months can drag.
The last month or two can be particularly slow, with both of you keen to get to the interesting bit. It can also be difficult because the pregnancy is all your friends can family talk about.
She's pregnant and you're going to be a dad. Try to stay good-humoured.
8. She might not sleep well
Turning over in bed when you're fully pregnant is quite a task, and most women wake up each time.
You might wake up with her, given all that movement, leaving you both tired before the baby is even born.
9. Sweet dreams
Many women dream more frequently when pregnant.
Nobody is sure why, but it could be caused by hormonal changes or disturbed sleep patterns.
These dreams are often particularly vivid, with imagery that suggests fertility and birth, such as forests and oceans.
If your partner feels the need to tell you about her dreams in the morning, don't make the mistake of being bored by them.
You know how your partner reacts first thing in the morning, when you press on her bladder for laughs?
When she's pregnant the baby does that all the time, and many women feel a constant need to urinate.
It's important to keep drinking, so the only solution is for her to keep going to the toilet.
Don't plan too many long journeys.
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Last updated: February 2015