Pregnancy is a subject that generates a lot of paper. Bookstores and libraries devote not just shelves but entire aisles to it. At your first prenatal visit, your doctor will likely load you down with armfuls of pamphlets that cover every test and trimester.

But despite all this information, pregnancy can take any soon-to-be parent by surprise.

What the Doctor May Leave Out

If your doctor hasn't mentioned the following topics during your visits, he or she isn't purposefully ignoring the information. More likely, your doctor hasn't brought them up because pregnancy affects women in different ways. For example, some pregnant women experience morning sickness in the morning, some feel it all day, and some never have it.

Or your doctor might not mention something because it doesn't have a medical focus — a doctor may not have any more insight into your increasing shoe size than your neighbor does! Also, some women may think questions about breast size or hemorrhoids are too personal or embarrassing to ask their doctors.

Any concerns you have about your or your baby's emotional or physical health, regardless of how unrelated or trivial they may seem, should be discussed with your doctor. He or she has seen many expectant parents, some less worried and some more worried than you, and can reassure you when there is no problem or give you more information when there is one.

And if your doctor doesn't take the time to listen to your concerns or doesn't seem to take them seriously, you should feel free to get a second opinion.

Altered States

Pregnancy doesn't just change your body — it affects the rest of you, too.

1. The Nesting Instinct

Many pregnant women experience the nesting instinct, a powerful urge to prepare their home for the baby by cleaning and decorating. Or perhaps you'll want to tackle projects you haven't had time to do, like organizing your garage or closets.

As your due date draws closer, you may find yourself cleaning cupboards or washing walls — things you never would have imagined doing in your ninth month of pregnancy! This desire to prepare your home can be useful because it will give you more time to recover and nurture your baby after the birth. But be careful not to overdo it.

2. Inability to Concentrate

In the first trimester, fatigue and morning sickness can make many women feel worn out and mentally fuzzy. But even well-rested pregnant women may experience an inability to concentrate and periods of forgetfulness.

A preoccupation with the baby is partially the cause, as are hormonal changes. Everything — including work, bills, and doctor appointments — may seem less important than the baby and the impending birth. You can combat this forgetfulness by making lists to help you remember dates and appointments.

3. Mood Swings

Premenstrual syndrome and pregnancy are alike in many ways. Your breasts swell and become tender, your hormones fluctuate, and you may feel moody. If you suffer from premenstrual syndrome, you're likely to have more severe mood swings during pregnancy. They can make you go from feeling happy one minute to feeling like crying the next. You may be irrationally angry with your partner one day, then a coworker may inexplicably irritate you the next.

Mood swings are incredibly common during pregnancy, although they tend to occur more frequently in the first trimester and toward the end of the third trimester.

About 10% of pregnant women experience depression during pregnancy. If you have symptoms such as sleep disturbances, changes in eating habits (a complete lack of appetite or an inability to stop eating), and exaggerated mood swings for longer than 2 weeks, you should talk to your doctor.

Unexpected Effects of Pregnancy

4. Bra Size

An increase in breast size is one of the first signs of pregnancy. Breasts usually become swollen and enlarged in the first trimester because of increased levels of the hormones estrogen and progesterone. That growth in the first trimester isn't necessarily the end, either — your breasts can continue to grow throughout your pregnancy!

In addition to the size of your breasts, your bra size may be affected by your rib cage. When you're pregnant, your lung capacity increases so you can take in extra oxygen for yourself and the baby, which may result in a bigger chest size. You may need to replace your bras several times over the course of your pregnancy.

5. Skin

Are your friends saying you have that pregnancy glow? It's only one of many skin changes you may experience during pregnancy due to hormonal changes and the stretching of your skin to accommodate a larger body.

Pregnant women experience an increase in blood volume to provide extra blood flow to the uterus and to meet the metabolic needs of the fetus. They also have increased blood flow to their other organs, especially the kidneys. The greater volume brings more blood to the vessels and increases oil gland secretion.

Some women develop brownish or yellowish patches called chloasma, or the "mask of pregnancy," on their faces. And some will notice a dark line on the midline of the lower abdomen, known as the linea nigra (or linea negra), as well as hyperpigmentation (darkening of the skin) of the nipples, external genitalia, and anal region. These are the result of pregnancy hormones, which cause the body to produce more pigment.

The body may not produce this increased pigment evenly, however, so the darkened skin may appear as splotches of color. Unfortunately, chloasma can't be prevented, but wearing sunscreen and avoiding UV light can minimize its effects.

Acne is common during pregnancy because the skin's sebaceous glands increase their oil production. And newly formed pimples might not be the only evolving spots on your face or body — moles or freckles that you had prior to pregnancy may become bigger and darker. Even the areola, the area around the nipples, becomes darker. Except for the darkening of the areola, which is usually permanent, these skin changes will likely disappear after you give birth. Many women also experience heat rash, caused by dampness and perspiration, during pregnancy.

In general, pregnancy can be an itchy time for a woman. Skin stretching over the abdomen may cause itchiness and flaking. Your doctor can recommend creams to soothe dry or itchy skin.