Things are changing fast. You’re reaching the home stretch of the first trimester (we know, finally!) at 12 weeks which means your hormones are likely to tone things down a bit -- which might make you feel a little less emotional! And it will probably help the symptoms subside a bit, too. One warning though: your morning sickness and fatigue might get replaced by headaches and dizziness. But we think that’s a reasonable trade-off. The other big change? Baby’s almost done developing her body’s important systems and parts, which means, it’s mostly about getting bigger and more mature from here on out. Around week 12, you might want to know more about baby, so you’re probably having genetic testing done to determine her risk of birth defects or other problems. This can be a little scary -- and confusing -- so be sure to ask your OB plenty of questions, and know that it’s much more likely baby’s A-OK than anything else.

your baby's the size of a plum! 

The average fetus at 12 weeks is about 2.1 inches long and .49 ounces. Now that she's got pretty much all her parts, her main job is to keep on growing.

Your baby at 12 weeks

• Most of her critical systems are fully formed!
• She's about to enter the growth and maturation stage, in which her organs and tissues will grow and develop rapidly.
• She's now developing her reflexes -- if you poke her body, she'll likely move.
• She's opening and closing her fingers and curling her toes, too.
• Her brain is developing fast!

Pregnancy symptoms at 12 weeks

• Your hormones should calm down a bit -- if not now, soon. That means less nausea and fatigue (yay!).
• More vaginal discharge, to protect your, um, lady parts from infection.
• A noticeably bigger belly. Do you look pregnant now?
• Headaches and dizziness may start to intensify around this time, which could be caused by hormones, vision changes, drops in blood sugar, dehydration or stress.

Your must-do's

• Schedule your monthly prenatal visit to the OB, if you haven't already.
• Understand the signs of dehydration, or make sure you are sufficiently hydrated.

Your nice-to-do's

• Tell your friends and family you're pregnant (if you haven't already revealed it!).
• If your ready, tell your boss, and talk about how your duties will be covered while you're on maternity leave.

 Source: pregnant.thebump.com