© Amélie Benoist / Science Source

Breastfeeding is like a hike through the woods: Natural, but not always simple. In fact, it can be challenging, breathtaking, and full of the unexpected.

Here are the big breastfeeding surprises moms reported to us:

The hormones can be intense

It's the ultimate paradox. Here's this odd-looking creature sporting a belly-button stump, acne, and peeling skin. He can't even hold a decent conversation, let alone get you a cup of coffee – and yet whenever you nurse him, you're filled with head-over-heels devotion. What's up with that? We have one word for you – oxytocin.

This powerful hormone is responsible for breast milk "letting down," or moving to the front of the breasts. And it also happens to be the same chemical released in the brain when a person falls in love, says Laura Viehmann, assistant professor of pediatrics at Brown University and spokesperson for the American Academy of Pediatricians. No wonder you couldn't care less about all that spit-up and poop! You're too busy swooning.

Another hormonal effect of nursing – particularly in the newborn period – is a feeling of deep relaxation, which can easily tip over into drowsiness. "It's the same kind of sleepiness people feel after a big meal," Viehmann says. And just like that post-Thanksgiving sedation, it's difficult to resist. "I can be wide awake and full of energy, but I sit down to breastfeed and I'm half passing out," says one mom.

Viehmann's advice? Recognize that the drowsiness has a purpose and give in to it, even if only for a ten-minute catnap. "Research shows that mothers who take advantage of these small naps will achieve an extra one to two hours of sleep per day," Viehmann says. Just make sure you nurse in a safe place where your baby can't fall or get trapped in a cushion if you doze off.

Unfortunately, not all the hormonal effects of nursing are positive. Some women report uncomfortable sensations before or during letdown, such as an uneasy feeling in the stomach, weakness, sweating, and even an odd sense of melancholy. These feelings are often temporary and can be replaced by more positive ones.

But if you're concerned about how you're feeling, or if you're having problems with breastfeeding, don't hesitate to check in with your doctor.

Breastfeeding helps (some) women lose their pregnancy weight

As your baby grows from a fragile-boned newborn into a delicious butterball, you may notice your own weight dropping. You can thank nursing for transferring those pounds.

"Breast milk is a high-fat, high-caloric food," says Robert Wool, associate professor of obstetrics and gynecology at Tufts University. "And the baby basically sucks those calories right out of the mother's body." Hence, the incredible shrinking mommy. As one mom says, "The weight just fell off."

However – and unfair as this seems – the nursing weight-loss plan doesn't work for everyone. Some moms find their metabolism slowing to a frustrating crawl. "I nursed my son for 27 months and it didn't help me lose weight. Then I lost 15 pounds within about two weeks after weaning," one mom reports.

In fact, in a poll of BabyCenter moms, 40 percent say breastfeeding didn't help them drop pounds while 60 percent say it did. Is there a physiological difference between the two groups?

Possibly, says Viehmann, although there's not a lot of research data in this area yet. "One of the breastfeeding hormones is also involved in digestion. For some nursing women, this hormone may become more efficient, so they don't need as many calories," she says.

Your breasts can leak – a lot

When it comes to leakage, your breasts may seem to have tiny minds of their own, particularly in those early postpartum weeks. Like an internal alarm clock, they may dribble – or spray – milk when it's time for a feeding, says nurse and lactation consultant Claudia Perry. They may also leak whenever you hear your baby cry or, for that matter, when you hear any baby cry. Photographs, videos, or just thoughts of your baby can get that dairy faucet pumping.

"Even baby animals and babies on television can set me off," one mom reports. Another says, "At first, I couldn't leave the house without nursing pads because I knew the second I saw or heard another baby, or even thought about my baby, I'd leak everywhere."

Once again, oxytocin – the hormone responsible for your letdown reflex – is the culprit. Like a good party host, your body knows that it's better to have too much food available than not enough. While those wet spots on your blouse can be a bit embarrassing, think of the leaking as nature's way of making sure your baby always has enough to eat.

Some women, says Perry, have occasional leaking long after they've weaned their babies – sometimes even a year later! It just goes to show that we should never underestimate the power of those hormones.

You can be lopsided

Feeling a little uneven? It's not your imagination. Many moms find that one breast consistently produces more milk than the other. If this is the case for you, you can chalk it up to the fact that you have a different number of milk-making ducts on each side. "Humans aren't perfectly symmetrical," says Perry. "Just as one foot can be bigger than the other, one breast can have more ducts than the other."

Of course, what this means is that the more productive breast may be bigger as well as fuller. Again, this is normal. "I am completely lopsided! Righty is way bigger than lefty – probably at least a cup size. I call the right side the workhorse," says one mom.

You can also cause uneven milk production if you feed your baby more from one breast than the other. (The breast you use more will produce more milk.) But if you're giving each breast equal time and still noticing a difference in output, it's likely a duct issue.

You can't change the number of ducts you have. The fuller side will probably remain more productive the entire time you nurse your baby – and it will likely be more productive for your next baby as well.

Your breast milk is perfectly tailored to your baby

Imagine if every single time you were hungry, you were served a delectable, satisfying meal that contained the perfect balance of electrolytes, fats, and nutrients for your body at that particular time. Welcome to your baby's world.

"The joke is that breast milk is a 'soup to nuts' meal," says Miriam Labbock, pediatrician and director of the Carolina Global Breastfeeding Institute at the UNC School of Public Health, meaning it's a full-course feast. "The first milk is more watery, so it addresses the baby's thirst. As the feeding continues, the milk becomes higher in fat. It's like starting with broth and ending with a hot fudge sundae." This setup allows your baby to get her electrolyte needs met at the beginning of the feeding and her energy needs met with the creamier milk at the end.

In addition, says Labbock, starting with the watery part is easier on the baby. "This allows the infant to avoid having to fight with the heavy cream right away," she says. "The cream comes only after the milk is flowing nicely."

Amazingly, your breast milk gives your baby exactly what she needs immunologically as well. "The components of the milk shift so that it always complements whatever antibodies the baby is low on at that particular time," Labbock says. This is why breastfeeding can actually keep your baby from getting sick.

As if this weren't enough, your breast milk changes throughout the day, with more sedating properties being released in the evening. It also changes as your baby grows older to meet her ever-changing nutritional needs. In short, it's the perfect food. And judging from the look of drunken satisfaction on a well-fed baby's face following a feeding, it tastes pretty good, too.