Although every baby develops differently, this guide will give you an idea of how your baby is growing and developing throughout your pregnancy.
The blastocyst, as the fertilized egg is called at this stage, completed its journey from your fallopian tube where it was fertilized to your uterus in the first week and has since settled into your nutrient-rich endometrial lining and been dividing and growing feverishly.
By the end of this month it has grown to about 1/4 of an inch long, and along with its extended tailbone that makes it look like a tadpole, it already has a head and mouth, eyes (partially covered by eyelid folds), buds that will become arms and legs, the beginning of lungs and a digestive tract, and a heart that will begin to beat at the end of this month. In the meantime, an early version of the placenta, the chorionic villi, and the umbilical cord - which delivers nourishment and oxygen to the baby - are already on the job.
Your little blastocyst is now 10,000 times larger than it was when fertilized!
You have missed your first period and hormones are surging through your body, preparing you for the coming months. You may also notice your breasts are swollen and tender.
Your baby is now just under one inch long (measured crown to rump), or about the size of a grape, and is considered an embryo. Its little heart is beating away and he or she is wriggling in your uterus, even though you will not be able to feel the movements for many more weeks.
If you are carrying a baby boy, his penis is beginning to appear, although it won't be big enough to see on an ultrasound for another couple months. Its liver is churning out large amounts of red blood cells, and will continue to until the bone marrow forms and takes over this function. Week eight marks the beginning of a very busy developmental stage: its face continues to change as the ears, eyes and the tip of the nose appear; the intestines start to form in the umbilical cord; and your baby's teeth begin to develop under the gums.
You may be experiencing one of the least-favorite symptoms of pregnancy: morning sickness. If so, keep some crackers by your bed and eat a few before getting up in the morning. Keeping a little food in your stomach at all times can help stave off the waves of nausea. Your breasts are probably still sore and your areolas and nipples have darkened, and you may have put on a few pounds (although some women don't and a few even lose a couple pounds during the first trimester due to morning sickness and lack of appetite). You're probably feeling tired and can't wait to climb into bed at the end of the day, and all those hormones raging through your body may have put you on an emotional roller coaster.
Take heart - the nausea, fatigue, and mood swings should all disappear by the end of next month as you near the beginning of your second trimester.
Your little fetus is about 2.5 inches long (crown to rump) and weighs nearly an ounce. His or her reflexes are functioning, and the digestive tract is active and secreting bile - all to prepare your baby for life outside of your body.
Stem cells, the "mother cells" that will become heart, brain, liver, bone, blood, nerve, and immune cells, continue to differentiate to form your baby's major organs. He or she now looks more like a little person and the head is the biggest part of its body - accounting for nearly 1/2 of its total size. He or she has eyes, a chin, bits of teeth, a nose, and a forehead and the fingers and toes are almost fully formed.
You may begin to regain some of your energy and appetite about now, and although you probably still don't look pregnant, your pants may be getting a little tight. You may also experience indigestion, bloating, and gassiness, thanks to all the progesterone your body is producing. To help relieve some of the discomfort, eat several small meals instead of three bigger ones.
Your little one is six to seven inches long and weighs about five ounces now, and is developing reflexes, such as sucking and swallowing and may begin sucking his or her thumb anytime now.
His heart pumps about 25 quarts of blood a day, his or her head is starting to become more erect, and the eyes have moved from the side of her head to the front of her face. You may be able to find out whether it's a boy or a girl during an ultrasound as the external sex organs are developed and visible. He or she is also big enough that you may begin to feel him wiggle and kick inside you.
Many women say their second trimester is the most comfortable, fun period of their pregnancy - past the fatigue and nausea of the first trimester, yet not cumbersome and uncomfortable as in the third. This is a great time to begin or resume your exercise routine. Regular, moderate exercise can keep you and your baby healthy, as well as ease some pregnancy symptoms and even ease labor.
Your baby is nearly a foot long and weighs almost one pound by the end of this month and is sleeping in regular intervals. He or she can hear your heart beat and other sounds outside your body and you may notice that he or she reacts to sudden noises like a door slamming.
Fine hair, called lanugo, covers your baby's body, as does vernix, a creamy coating that protects your baby's delicate skin from months of submersion in water.
You may be beginning to feel the stress of the added weight you're carrying, which can cause bowel problems, leg cramps, fatigue, and an increased heart rate. Calcium will help with leg cramps, drinking lots of water can help relieve constipation, and get enough rest - growing a new little person is hard work and you deserve a break!
Your baby is about 11 to 14 inches long (head to toe) and weighs a hefty 1.5 pounds. His or her eyelids begin to part and the eyes are open for short periods of time. Her lungs are continuing to develop and she is practicing breathing - she may even have her first case of the hiccups soon.
He or she has fingerprints, eyebrows, and eyelashes.
As your belly begins to bulge and the skin is stretched, you may begin to experience tight, itchy skin. Daily application of a moisturizing lotion can help relieve some of the discomfort. Your extremities may be increasingly swollen - especially by the end of the day or if you spend a lot of time on your feet. Wear supportive, low-heeled shoes and elevate your feet whenever possible. If you notice dramatic swelling over a short period of time, call your doctor. This may be a sign of preeclampsia.
By the end of this month, your baby is about 15 inches long and weighs a little over 2 pounds. His or her eyes are open fully now and you may notice that she'll turn toward a light source, such as a flashlight placed against your belly.
He or she now has taste buds and is putting on more layers of fat in anticipation of life outside of your cozy womb. As your baby packs on all this poundage and length, he or she is quickly running out of room and you may notice a decrease in the intensity of kicks and jabs, but you may be able to discern the shape of an elbow or heel through your belly!
You may begin to feel practice contractions, called Braxton Hicks . Don't panic - these aren't the real thing unless they occur regularly and you have more than four in one hour. Now that you're probably seeing your doctor on a bi-monthly basis, tell him or her if you notice any signs of preterm labor.
Your baby is getting ready for birth and is probably in the head-down position. He or she is approximately 17 inches long and weighs about 5 pounds.
Brain growth is dramatic this month while most of the other organs are ready to go, with the exception of the lungs, which still need a few more weeks of development. His or her little fingernails continue to grow and he may even need a trim after birth!
You may be feeling very tired and uncomfortable at this stage. Your baby is pressing up against your spinal column, which can give you a terrible back ache and make it impossible to get comfortable. Try sleeping with a body pillow to support your belly and your back. Your Braxton Hicks may also be increasing in strength and frequency and your breasts may begin leaking colostrum, all of which may add to your excitement about your baby's imminent arrival. The big day is almost here!
Your baby is approximately 20 inches long and weighs about 7 pounds, although he or she is still gaining about an ounce a day. He or she is preparing for birth this month by shedding most of the lanugo and vernix that has been covering and protecting his skin.
Your baby can survive outside your body now, even if he or she is born a little early (37 weeks is considered full-term). The lungs are still secreting surfactant, the substance that will keep the lungs from sticking to each other and inflate fully after she takes that first breath of air.
Scientists still don't know precisely what triggers labor to start, which could happen any time now. Most babies are born within two weeks before to two weeks after their due date. You are probably seeing your doctor on a weekly basis now (read more on your next ob appointment) and he or she will be checking your cervix for signs of effacement and dilation - two sure signs that your baby is on its way!