Weekly Pregnancy Calendar the First Trimester: Your Baby and Your Development

A pregnancy is, on average, forty weeks. Each and every week is a new and exciting experience. The following is a week by week pregnancy calendar for each trimester to give a general idea of what to expect each week of your pregnancy, as well as how your baby will be growing.

Month One, Week One:

How your baby is growing:

Pregnancy is calculated from the first day of your last period and not from conception. During week one of your pregnancy your baby hasn't even begun yet. Your uterus has shed its lining and is preparing to release an egg. You're about to ovulate!

How you may be changing:

You will likely feel like you're on your period. Now is the time to stop any birth control methods and begin acting pregnant. How do you act pregnant, one might ask? This doesn't mean eat ice cream with pickles, but begin taking prenatal vitamin tablets and cease any drug and alcohol use. The condition of your body effects your new baby even before the baby has been conceived. Make sure Dad is also being health conscious at this point. The health of his sperm will also affect your baby.

Month One, Week Two:

How your baby is growing:

Your period has ended and your uterine lining has thickened. You may be ovulating. Sometimes ovulation will cause mittleschmerz, or pain in the side, but most women don't feel ovulation at all. There are a few ways to know if you're ovulating. You can watch the calender, ovulation often occurs half way through your menstrual cycle, which would be about two weeks after your last period began. You can also chart your basal body temperature. Body temperature will become low during ovulation and then rise immediately after, so by charting this effect every month you can get an idea which days you'll be ovulating. Cervical mucus will also increase just before ovulation and change consistency after ovulation. If all else fails you can just buy an ovulation predictor kit at your local store.

How you may be changing:

You're probably feeling much better now that your period is over, and that's a good thing because it's time to get busy in the bed room. If you've been taking your prenatal vitamins you may see some increase in nail and hair growth. You may also feel more energetic. Fathers to be should also continue taking good care of themselves, and switch to boxers. That's right, even the type of underwear your mate wears can affect sperm. "Tighty Whities" will overheat testicles and can significantly lower sperm count. During ovulation you want to expose your eggs to as much sperm as possible so take a break from reading and get busy.

Month One, Week Three:

How your baby is growing:

If you are pregnant your baby has just begun its journey to becoming an adorable bundle of love. Fertilization occurs in week three, or the meeting of your egg and your spouse's sperm. The baby is nothing more than a tiny bundle of cells in an egg. This is called a zygote. It will take four to seven days for your fertilized egg to reach it's new home in your uteran wall. Cell division began immediately following fertilization, your baby is already growing! Your genetics have already determined everything from eye color to height including well over two-hundred different characteristics. Once the zygote reaches your uterus it is medically referred to as a blastocyst, though you may want to start thinking up names yourself. At this point your baby is 0.1 to 0.2 millimeters in diameter.

How you may be changing:

You proved you know all about the birds and the bees last week and your egg should be fertilized! Congratulations! You're probably going to be a parent. How can you be sure? It's during week two that you will experience implantation bleeding if you've successfully become pregnant. Implantation bleeding is just a bit of spotting three to seven days after intercourse and it is perfectly normal. Your body has also begun to produce hormones that can be detected by a pregnancy test. Although, these hormones may not be strong enough to obtain a positive result just yet.

Month One, Week Four:

How your baby is growing:

If you are pregnant your baby has reached its destination in the uterus and is setting up shop. The chorionic villi, or hair like projections that will later form your placenta have now begun to grow. Until the placenta is fully formed your baby will live in a gestational sack, which is sort of like an egg yolk. This yolk will feed your baby for its first few weeks. A transvaginal ultrasound will be able to reveal this sack now. As cells continue to divide an amazing amount of important parts of your baby are beginning to form, including the heart!

How you may be changing:

Now is the time to break out that pregnancy test. By week four hormone levels are unquestionably high enough to receive a definitive yes or no and settle the question once and for all, are you pregnant? Many women begin to feel the first tell-tale signs of pregnancy at this point as well. You may feel more tired than usual, experience mood swings, find yourself having to pee far more frequently, and may have tender or swollen breasts. Not all women experience symptoms in week four, or at all for that matter. Those are the lucky ladies.

Month Two, Week Five:

How your baby is growing:

Week five is a busy week for baby as it develops the neural tube which will soon become a spinal cord. The brain begins to develop this week as well, and the heart finishes up and begins to beat. You'll be able to hear that heart warming "thump, thump" as well at your prenatal appointment. If you haven't begun prenatal care yet that's okay, many practitioners won't even see you until you've missed two periods. This cuts down spending on false pregnancies. Your pregnancy test revealed a positive, and you can have that aforementioned transvaginal ultrasound if you can get an appointment this early. The yolk is ninety percent complete and your baby is about 1.5 to 2.5 millimeters in length. This is roughly the size of a grain of rice.

How you may be changing:

If you felt tired last week, you really are feeling it this week. Breast tenderness will also continue. You should invest in comfortable bras at this point and remember to leave a little growing room. Some women will also experience more cramping or even a feeling of fullness in the uterus during week five. The surge of hormones in your body can cause symptoms similar to those of the menstrual cycle. This can commonly include headache. Avoid aspirin if you do opt for pain relief. Aspirin can be harmful to your baby even at this early stage. Consult your health care provider before taking any over the counter medication, including herbal or home remedies.

Month Two, Week Six:

How your baby is growing:

Another busy week for baby. Almost all of the vital organs have now begun to form, this is why avoiding hazards to your babies' health, such as alcohol, is important from day one of your pregnancy. Your baby is now four to six millimeters from crown to rump, which is about the size of a skittle. It's inner ear and larynx are almost complete, as well as the development of the placenta. Although, the placenta won't take over the nutritional support for the gestational sack until around week twelve. Tiny buds have also formed on your baby which will later become arms and legs. Currently your baby resembles a tad pole and even has gills and a tail!

How you may be changing:

Week six is the wonderful week in which most mothers-to-be experience their first bout of morning sickness. Don't be confused either, morning sickness does not necessarily occur in the morning, but can hit at any time. Pregnancy is full of surprises! Your breasts may become more tender and tingly. The areola, or area around the nipple, may begin to increase in size and darken. Your blood pressure will also begin to drop which may cause light-headedness and you may also experience more of those fantastic head aches. Are you in need of a bit of positive life changes? It's not all bad, though sometimes it may seem that way. Also, if you happen to have a feline friend someone else officially has litter duty, not you. Cat feces can cause Toxoplasmosis, which causes flu like symptoms that can be very harmful to your baby.

Month Two, Week Seven:

How your baby is growing:

This week your baby becomes more humanoid in appearance. It is now forming hand plates, finger nail beds, a mouth, nostrils, and teeth buds. Vital organs continue to form with the lungs, liver, and digestive track finishing up. The genital tube is also now complete, though even with an ultrasound gender won't be visible yet. Your baby now weighs about as much as a chocolate chip and is seven to nine millimeters in length. This may seem small, but that's one-thousand times larger than the original fertilized egg! Your baby has really grown, and that tiny heart beat you may have heard last week is circulating blood through it's body. A body that can, at this point, move in response to cell communication due to brand spanking new nerve channels and muscle connections.

How you may be changing:

Your hormones are going to continue to go crazy in week seven, which may even cause acne flare ups. A mucus plug is forming in your cervix which will keep your new baby safe and sound in the uterus. This plug makes sex during pregnancy even safer, because it guards against infection. You may also start to notice your waist line diminishing, though some women don't begin to gain weight this early. If your experiencing cravings which are adding to this vanishing line, try changing brands of your prenatal vitamins. Pregnancy cravings are the bodies way of obtaining vitamins and minerals it's missing.

Month Two, Week Eight:

How your baby is growing:

The outer cells of the gestational sack have now connected to your blood supply and it's a good thing too, your baby is going to need all your bodies support this week as it grows in leaps and bounds. Toes, lips, outer ears, eyelids, intestines and gonads develop this week. That last one, the gonads, will be either ovaries or testicles meaning you officially have a girl or a boy now! Movement occurs for the first time this week as those nerves and muscles become more mature, and joints such as the elbow appear. You probably won't be able to feel these tiny movements yet because your baby is only eight to eleven millimeters in length and weighs less than an ounce. That's about the size of your average gum drop. Your babies bones are also beginning to harden, or ossify.

How you may be changing:

Morning sickness is in full swing for most women at this point, and you may also experience abdominal pain. This is because your uterus is becoming heavier and beginning to place strain on the round ligaments and muscles in the pelvis. The pain will be sharp and on either side of the lower abdomen, this is normal. However, if pain remains constant you should seek medical care. Light red or brown spotting is not a reason to reach for the phone in week eight, and is quite common. If the bleeding becomes heavy or clot-like you may be having a miscarriage so pay close attention to the flow. If you have questions regarding miscarriage, pregnancy, or parenting now is an excellent time to enroll in pregnancy classes which will cover everything from breast feeding to labor breathing techniques.

Month Two, Week Five:

How your baby is growing:

Week five is a busy week for baby as it develops the neural tube which will soon become a spinal cord. The brain begins to develop this week as well, and the heart finishes up and begins to beat. You'll be able to hear that heart warming "thump, thump" as well at your prenatal appointment. If you haven't begun prenatal care yet that's okay, many practitioners won't even see you until you've missed two periods. This cuts down spending on false pregnancies. Your pregnancy test revealed a positive, and you can have that aforementioned transvaginal ultrasound if you can get an appointment this early. The yolk is ninety percent complete and your baby is about 1.5 to 2.5 millimeters in length. This is roughly the size of a grain of rice.

How you may be changing:

If you felt tired last week, you really are feeling it this week. Breast tenderness will also continue. You should invest in comfortable bras at this point and remember to leave a little growing room. Some women will also experience more cramping or even a feeling of fullness in the uterus during week five. The surge of hormones in your body can cause symptoms similar to those of the menstrual cycle. This can commonly include headache. Avoid aspirin if you do opt for pain relief. Aspirin can be harmful to your baby even at this early stage. Consult your health care provider before taking any over the counter medication, including herbal or home remedies.

Month Two, Week Six:

How your baby is growing:

Another busy week for baby. Almost all of the vital organs have now begun to form, this is why avoiding hazards to your babies' health, such as alcohol, is important from day one of your pregnancy. Your baby is now four to six millimeters from crown to rump, which is about the size of a skittle. It's inner ear and larynx are almost complete, as well as the development of the placenta. Although, the placenta won't take over the nutritional support for the gestational sack until around week twelve. Tiny buds have also formed on your baby which will later become arms and legs. Currently your baby resembles a tad pole and even has gills and a tail!

How you may be changing:

Week six is the wonderful week in which most mothers-to-be experience their first bout of morning sickness. Don't be confused either, morning sickness does not necessarily occur in the morning, but can hit at any time. Pregnancy is full of surprises! Your breasts may become more tender and tingly. The areola, or area around the nipple, may begin to increase in size and darken. Your blood pressure will also begin to drop which may cause light-headedness and you may also experience more of those fantastic head aches. Are you in need of a bit of positive life changes? It's not all bad, though sometimes it may seem that way. Also, if you happen to have a feline friend someone else officially has litter duty, not you. Cat feces can cause Toxoplasmosis, which causes flu like symptoms that can be very harmful to your baby.

Month Two, Week Seven:

How your baby is growing:

This week your baby becomes more humanoid in appearance. It is now forming hand plates, finger nail beds, a mouth, nostrils, and teeth buds. Vital organs continue to form with the lungs, liver, and digestive track finishing up. The genital tube is also now complete, though even with an ultrasound gender won't be visible yet. Your baby now weighs about as much as a chocolate chip and is seven to nine millimeters in length. This may seem small, but that's one-thousand times larger than the original fertilized egg! Your baby has really grown, and that tiny heart beat you may have heard last week is circulating blood through it's body. A body that can, at this point, move in response to cell communication due to brand spanking new nerve channels and muscle connections.

How you may be changing:

Your hormones are going to continue to go crazy in week seven, which may even cause acne flare ups. A mucus plug is forming in your cervix which will keep your new baby safe and sound in the uterus. This plug makes sex during pregnancy even safer, because it guards against infection. You may also start to notice your waist line diminishing, though some women don't begin to gain weight this early. If your experiencing cravings which are adding to this vanishing line, try changing brands of your prenatal vitamins. Pregnancy cravings are the bodies way of obtaining vitamins and minerals it's missing.

Month Two, Week Eight:

How your baby is growing:

The outer cells of the gestational sack have now connected to your blood supply and it's a good thing too, your baby is going to need all your bodies support this week as it grows in leaps and bounds. Toes, lips, outer ears, eyelids, intestines and gonads develop this week. That last one, the gonads, will be either ovaries or testicles meaning you officially have a girl or a boy now! Movement occurs for the first time this week as those nerves and muscles become more mature, and joints such as the elbow appear. You probably won't be able to feel these tiny movements yet because your baby is only eight to eleven millimeters in length and weighs less than an ounce. That's about the size of your average gum drop. Your babies bones are also beginning to harden, or ossify.

How you may be changing:

Morning sickness is in full swing for most women at this point, and you may also experience abdominal pain. This is because your uterus is becoming heavier and beginning to place strain on the round ligaments and muscles in the pelvis. The pain will be sharp and on either side of the lower abdomen, this is normal. However, if pain remains constant you should seek medical care. Light red or brown spotting is not a reason to reach for the phone in week eight, and is quite common. If the bleeding becomes heavy or clot-like you may be having a miscarriage so pay close attention to the flow. If you have questions regarding miscarriage, pregnancy, or parenting now is an excellent time to enroll in pregnancy classes which will cover everything from breast feeding to labor breathing techniques.

Be sure to read all about your next two trimesters to learn more tips, advice and forewarning to come.