It's 10 p.m., and your tummy is screaming for a handful of frosted animal crackers and a tall glass of chocolate milk. Or maybe it’s a schmear of pimiento cheese on a big dill pickle. Or even some sauerkraut and pickled pigs' feet. Rest assured, Mom-to-be, you're in good company.

A majority of U.S. women crave specific foods during pregnancy, research shows. Sweets, fruits, fast foods, pizza and the fabled pickles and ice cream often top the list.

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"My craving? Tomatoes and cotton candy, ideally eaten together," one mom recalled. "With my second, I craved birthday cake!" said another. "I could eat a whole cake." Added a third: "I would eat so many Oreos they made me ill — I promised no more and would eat them again the next day."

What's causing my cravings?

Exactly why expectant moms have food cravings is a matter of continuing debate. It used to be thought that a hunger for a particular food was a sign that a woman lacked the nutrients the food contains.

As researchers dig deeper, though, that theory has largely fallen out of favor. Changing hormones are a likely culprit, affecting the way some foods smell and taste.

A recent study in the journal, Nature Metabolism, noted that just like people, pregnant mice have food cravings. Researchers linked theirs to specific kinds of brain activity and the chemical messenger dopamine, which plays a role in experiencing pleasure.

Will my food cravings ever stop?

A University of North Carolina - Chapel Hill team that conducted focus groups with 68 pregnant women reported that cravings for specific tastes, textures or food combos start early in pregnancy and peak during the second trimester. For the most part, moms viewed them as biologically based and, therefore, out of their control.

If it's all a matter of biology, isn't it OK to give in to my food cravings?

Moderation is the key. If you're craving a lot of unhealthy foods, such as candy or chips, go easy to avoid excessive weight gain, dental problems and most importantly gestational diabetes. Nemours KidsHealth points out that you only need about 340 to 450 extra calories a day during pregnancy, roughly the amount in a cup of cereal and 2% milk.

Are food cravings ever dangerous?

Some women crave non-food items like clay, cornstarch, laundry starch, dirt or even soap. That's called pica and may be a sign that you have an iron or zinc deficiency. Be sure to let your health care provider know immediately if this happens to you.

How can I overcome my food cravings?

Eating regular, healthy meals can help prevent sudden attacks of hunger, so keep your pantry stocked with nutritious nibbles, PregnancyBirth&Baby recommends. Limit high-sugar, high-salt snacks in your pantry. Don't shop for groceries when you're hungry, and choose foods that will keep you full longer, such as whole grain breads, baked beans, rolled oats and fresh fruit. Drink plenty of water.

Among strategies cited by participants in the UNC study were eating frequently to prevent hunger, exercising, sleeping and substituting a healthier food (think: carrot, celery sticks or fresh fruit) when a craving for sweet or crunchy strikes.

Considering the health implications on your baby can be helpful, too. (In the mouse study, persistent craving behavior had long-lasting health effects on offspring, especially males, including excess weight and increased susceptibility to eating disorders.)

I feel guilty when I indulge. Should I?

If all else fails, rest assured you won't be the only mother-to-be who gives in to these strong cravings. "The most common strategy reported was consuming the craved food item," the UNC study noted, adding, "Women stated that resisting the craved food was ineffective, and that the craving would intensify, causing them to eventually consume more of the craved food." Again, try to go easy to avoid excess weight gain. But don't beat yourself up when you slip.

One more thing: Are there foods I should always avoid while I'm pregnant?

Yes, these include raw or unpasteurized dairy products, juices and cider; premade ham, chicken or seafood salad from the deli; raw or undercooked sprouts; and undercooked meat and poultry. Be selective with meat spreads or pâté and never eat unbaked dough or batter, advises. And remember, alcohol is always a big no during pregnancy.