Pregnancy Changes: Your Baby, Your Body

A trimester-by-trimester look at how you and your baby are growing.

Congratulations, you're pregnant! And you're probably curious and a little anxious about what's going to happen with your body and your baby over the next nine months. Here are some highlights.

For most women, especially first-time moms, it's almost impossible for anyone to tell they're pregnant during the first trimester. As a brand-new expectant mother, you're not showing much, if at all, and the only telltale outward sign might be that smile you just can't suppress.

But inside, both your baby and your body are already working at top speed, like the Apple factory before a new iPad launches. During the next 13 weeks, your baby will:

Grow from a tiny cluster of cells called a blastocyst (about the size of the head of a carpenter's nail) at week three of pregnancy to about 3 inches long (think the length of your car key) by week 12.Develop pigment in her eyes (still hidden behind sealed lids), form a tiny tongue with taste buds, and build a full four-chambered heart beating at about 180 beats per minute.Form all of her major organs and body systems -- a critical time of structural development. The period between eight and 10 weeks' gestation is perhaps the single most crucial time for fetal development, says Annette Perez-Delboy, MD, assistant professor of obstetrics and gynecology at Columbia University Medical Center and a maternal-fetal medicine specialist.

Meanwhile, there's a lot going on with you, too:

Your heart is rerouting much of its effort toward baby's temporary digs, your uterus. By the end of the first trimester, a significant amount of your cardiac output goes to the uterus.Your uterus is expanding from the size of a closed fist at conception to about the size of a small melon at 13 to 14 weeks.You may be noticing some of the first physical signs of pregnancy: breasts that are sore or tingle at the slightest touch, skin that's drier or oilier than usual, and "morning sickness" -- which may or may not restrict itself to the morning hours. As many as 70% to 80% of pregnant women have it, but not feeling morning sickness doesn't mean there's anything wrong with the baby.

Doctors often call this the "honeymoon trimester." Many women have put the nausea, sore breasts, and fatigue of the first trimester in the rear-view mirror. You're big enough to proudly show off a growing belly but not yet so ungainly that turning over in bed requires help.

During this trimester, your baby will:

Triple in length -- more or less -- from about 6 inches at week 14 or 15 to about 14 inches at 27 weeks. At the start of this trimester, she'll be about the size of a peach. By the end, she'll be more like an eggplant.Begin to hear the cacophony of sounds inside your uterus -- your pounding heart, swooshing blood as it rushes through your veins, and the gurgles of your stomach digesting lunch.Develop fine, downy hair called lanugo, which usually shows up first around the eyebrows and upper lip.

You're changing, too -- inside and out:

Most pregnant women begin to "show" during the second trimester. You likely gained less than 5 pounds during your first trimester, but now the number on the scale is edging relentlessly upward. As your second trimester proceeds, you'll gain an average of 1 to 2 pounds per week.Your internal organs will relocate to accommodate your growing uterus. Your rib cage will move upward by as much as 2 inches.Delivered right to your inbox, get pictures and facts on
what to expect each week of your pregnancy.

6 Post-Pregnancy Body Changes No One Tells You About

The top 6 post-pregnancy body changes that you never saw coming.

When you found out you were pregnant, you knew you were in for sleepless nights and countless diapers. But your female friends and family members who have walked the motherhood road before you forget to mention a few things, like bigger feet, a saggy belly, and little to no sex drive.

Here is expert insight into the post-pregnancy body changes you never saw coming.

Combine sleepless nights with the shock of motherhood and a drop in estrogen, and your sex drive takes a serious dive.

“It can take up to a year to feel like you are really back in the mood for sex,” says Hope Ricciotti, MD, an associate professor of obstetrics and gynecology at Harvard Medical School and a practicing obstetrician at Beth Israel Deaconess Hospital in Boston. “You are so focused on your child and your family that you have little to no time for yourself, and that includes sex.”

You’re also exhausted, stressed, and have almost no opportunity for romance for the first few months after baby is born to even think about the act that conceived your child, she says.

Mix these with estrogen levels that bottom back to normal post-childbirth, and sex drops to the tail end of your priority list.

“Estrogen levels rise during pregnancy, and fall abruptly after you give birth,” says Silvana Ribaudo, MD, an obstetrician at Columbia Medical Center in New York. “The change in estrogen levels means a woman’s sex drive is probably pretty low. It rebounds, but it does take time.”

"Elephant belly" is what Elizabeth Turkenkopf of Albany, N.Y., not-so-affectionately calls her midsection after having twins. Granted, she had two babies in her uterus instead of one, but her belly change isn’t uncommon.

“A lot of women experience loose skin on their belly after childbirth, after their uterus returns to its normal size,” Ricciotti says.

The uterus increases about five times its normal size during pregnancy, she says, so the skin needs to stretch to accommodate an organ the size of a small watermelon -- or two, in Turkenkopf’s case.

The problem is that stretched skin might stay stretched out.

“Its not the same as stretch marks, which lots of women try to prevent using creams,” Ricciotti says. “It’s loose skin, and it’s cosmetic.”

Turkenkopf's doctor told her the only way to get rid of it was through surgery. Now you have one less surprise post-baby, albeit an unpleasant one.

You give birth, you lose your belly, right? Not so fast.

“After you give birth, lots of women expect that their belly will return to its normal size almost immediately,” Ribaudo says. “That doesn’t happen. In fact, it takes about 6-8 weeks before the uterus is back to its prepregnancy size.”