Your Pregnancy Week By Week: Weeks 1-4

The sections of this document that are underlined and in bold are part of the graphic organizer used in class. Many test questions will come from these highlighted areas.

This document also is used in coordination with the Powerpoint Presentation called “Pregnancy Powerpoint” which contains images and links to video that match up with the week by week information below.

Weeks 1 and 2

Baby: Your baby is still just a glimmer in your eye. Although it's confusing to think about a pregnancy starting before your child is even conceived, doctors calculate your due date from the beginning of your last cycle since it's hard to know exactly when conception occurred. Mom-to-be: At the beginning of a cycle, an egg will travel down the fallopian tube, where it awaits fertilization. This all takes place about 14 days before the end of your cycle. This is the time you're most fertile. Only about 400 sperm will survive the arduous ten-hour journey to the egg, and only one will succeed in burrowing through its outer membrane. (It takes about 20 minutes for the lucky winner to find his way in.) Your practitioner counts 280 days from the first day of your LMP to determine your due date. That's exactly 40 weeks. Your due date is just an estimate, however. Only 5 percent of babies are born on their due date.

Week 3 - IMPLANTATION

Baby: If your egg and your partner's sperm have joined successfully, you will have a growing embryo: a group of about 100 cells multiplying and growing rapidly. Mom-to-be: You have only about a 20% chance of getting pregnant each month, and now you are pregnant. You won't notice any changes. It's too soon. Remember, you haven't even missed your period yet.

Week 4

Baby: The embryo, probably in about its second week of development, has multiplied to about 150 cells. Your baby is being nourished by secretions from the uterine lining. Layers of cells already are specialized according to functions. The embryo is about the size of a poppy seed. Mom: May show some early signs of pregnancy, like morning sickness, bloating, and frequent urination.

Week 5

Baby: Heart, brain, spinal cord, muscle and bones are beginning to develop. The placenta, which will nourish your baby, and the amniotic sac, which provides a warm and safe environment where the baby can move easily, are still forming, too. The embryo is about the size of a sesame seed. Mom-to-be: You'll want to schedule a visit to your OB-Gyn as soon as you suspect you're pregnant. Good prenatal care is one of the best assurances of a healthy pregnancy and healthy baby.

Week 6

Baby: The eyes and limb buds also are forming. A heartbeat can sometimes be detected by an ultrasound around now. This is also an extremely important time in the development of your baby, since between 17 and 56 days the embryo is most susceptible to factors that can interfere with its normal growth. The embryo is now about the size of a lentil. Mom-to-be: You may have gained a few pounds by now, but if you're experiencing morning sickness you may have lost weight, which is also normal. You're starting to notice some changes in your body: clothes getting a little tighter around the waist, weight gain in your legs and breasts. With a pelvic exam, your practitioner will be able to notice a change in the size of your uterus. Make sure you're following good prenatal habits, like eating right and taking your prenatal vitamins. Since the neural tube (which is the beginning of the central nervous system) has formed by now, taking folic acid to prevent spinal cord defects such as spina bifida, has been crucial. If you haven't already, stop smoking and drinking. Week 7

Baby: Leg buds are starting to look like short fins, and hands and feet have a digital plate where fingers and toes will develop. The heart and lungs are becoming more developed. By now the brain and spinal cord are growing from the neural tube. The embryo is about the size of a blueberry. Mom-to-be: You're still not "showing," but by now you're really feeling the changes in your body. You still may be experiencing morning sickness and the other symptoms of early pregnancy.

Week 8

Baby: Your embryo, now about in its sixth week of development, is about the size of a kidney bean -- 0.56 to 0.8 inches from crown to rump. Eyelid folds and ears are forming and even the tip of the nose is visible. The arms have grown longer and bend at the elbows. Places where fingers and toes eventually will grow are becoming notched. About 1/3 of the weight of the baby comes from the head. Mom-to-be: Your uterus, once the size of your fist, is now about the size of a grapefruit. You may feel some cramping or pain in your lower abdomen or sides, but that's because your uterus typically tightens or contracts throughout pregnancy.

Week 9

Baby: The embryo measures about 0.9 inches to 1.2 inches from crown to rump, or the size of a grape. Your baby now moves its body and limbs, and this movement can be visible during an ultrasound, but you won't be able to feel it yet. Mom-to-be: Your uterus is continuing to grow, and you may begin to see your waistline thickening. But unless you tell people the good news, your pregnancy still won't be noticeable to others. Weight gain is still small, since you could be experiencing food aversions, cravings, heartburn, indigestion, nausea and bloating. Mood swings and weepiness similar to PMS symptoms are common, too. Tip for the Week: Eat plenty of foods that contain calcium -- such as cheeses, sardines and broccoli -- to provide sufficient calcium for the development of your baby's teeth and bones.

STOP AND WATCH VIDEO AFTER WEEK 9.

Week 10

Baby: The baby is now officially called a "fetus" and is about the size of a kumquat. You might be reassured to know that most physical malformations, when they occur, have occurred by the end of this week, so the most critical part of your baby's development is safely behind you. But other developmental processes, such as those affecting behavior and intelligence, will continue throughout pregnancy. Eyes are covered by skin that will eventually split to form eyelids. Mom-to-be: You still probably don't show, but you may be wearing looser clothes. You may even be starting to eye maternity clothes, although you probably still don't need them. You may continue to feel tired and moody, but take heart: These symptoms shouldn't last too much longer.

Week 11

Baby: Your fetus, about the size of a fig, measures about 1.75 to 2.4 inches from crown to rump and weighs about three-tenths of an ounce. About now the rapid "swooshing" noises of the heartbeat can be heard through a Doppler sound-wave stethoscope. External genitalia are developing but difficult to distinguish through ultrasound characteristics, and the baby is swallowing and kicking, although you still won't feel it. Mom-to-be: Your uterus is almost big enough to fill your pelvis and may be felt in your lower abdomen. You may also experience changes in hair, skin, fingernails or toenails. Week 12

Baby: The fetus now measures about 2.5 inches, from crown to rump and weighs between three-tenths of an ounce and half an ounce. It is fully formed, from tooth buds to toenails, and is about the size of a lime. The baby's job now is to continue getting larger and stronger for the rest of your pregnancy. With the most critical development behind the fetus, the chance of miscarriage drops considerably after this week. Mom-to-be: Nausea and energy start to improve. You may be experiencing occasional headaches, dizziness and fatigue from hormonal changes. If it's your first baby, you still could be wearing loose-fitting clothes, but if you've had other pregnancies, you'll probably start to show earlier and may be in maternity clothes. The typical weight gain by now is about three to five pounds. Fathers-to-be might also experience pregnancy symptoms, called couvade or "hatching," during the third month and at delivery, including nausea, abdominal pain, appetite changes and weight gain. Most women develop stretch marks on their abdomen, breasts, hips or buttocks sometime during their pregnancy. They won't go away, but they'll usually fade after pregnancy. Despite claims from manufacturers, creams and oils don't minimize them. It depends on your skin's natural elasticity. Gradual rather than rapid weight gain may help, as well as avoiding excessive weight gain during pregnancy.

Week 13

Baby: Your fully formed fetus, now in about its 11th week of development, measures 2.6 to 3.1 inches from crown to rump and weighs between half an ounce and seven-tenths of an ounce -- about the size of a large shrimp. The head is still disproportionately bigger than the body, but the rest of the body is starting to catch up. In fact, your baby is growing rapidly these days. The face is starting to look more human, with eyes moving closer together. Toes and fingers are clearly separate, and ankles and wrists have formed. External genitalia are becoming visible. Intestines are shifting into their proper place, too. Mom-to-be: Your uterus has grown a lot. It's filling your pelvis now and starting to grow upward into your abdomen. It probably feels like a soft, smooth ball. If you haven't put on any weight yet because of morning sickness, you'll begin to now as you start to feel better. Week 14

Baby: Your baby measures about 3.2 to 4.1 inches from crown to rump now and weighs almost an ounce, roughly the size of an medium lemon. The ears are shifting from the neck to the sides of the head, and the neck is getting longer and chin more prominent. Facial features and unique fingerprints are all now fully developed. Your baby is beginning to respond to outside stimuli. If your abdomen is poked, the fetus will try to wriggle away. Mom-to-be: You're probably wearing maternity clothes now. Your skin and muscles are starting to stretch to accommodate your growing baby. You may notice some constipation because pregnancy hormones relax the bowel.

STOP AND WATCH VIDEO AFTER WEEK 14

Week 15

Baby: Your 13-week-old fetus now measures about 4.1 to 4.5 inches from crown to rump and weighs about 1.75 ounces. Its body is covered by an ultrafine hair, called lanugo, which is usually shed by birth. Eyebrows and hair on the top of the head are beginning to grow. He may even be sucking his thumb by now. Bones are getting harder. The fetus is about the size of an apple. Mom-to-be : Amniocentesis, which tests a small sample of amniotic fluid withdrawn by an ultrasound-guided needle, is usually performed between now and 18 weeks. It may be recommended if you're 35 or older or if your AFP or quadruple marker screen test results were suspicious.

Week 16

Baby: You may be able to hear the baby's heartbeat in the doctor's office with a stethoscope instead of only by ultrasound. The baby is about the size of an avocado. Mom-to-be: Within the next few weeks you may start to feel your baby move, called "quickening." It's often like a gas bubble or subtle fluttering movement. As it happens more regularly, you'll know it's your baby. There are other physiological changes happening in your body. Increased blood volume to support your growing fetus may produce nosebleeds, and leg veins may become more apparent. Your uterus is shifting so you may not have to urinate so much.

Week 17

Baby: Your baby, now about in its 15th week of development, measures about 4.4 to 4.8 inches from crown to rump and has doubled in weight in the last two weeks to about 4-5 ounces, and is about the size of a turnip. Fat begins to form, helping your baby's heat production and metabolism. The lungs are beginning to exhale amniotic fluid, and the circulatory and urinary systems are working. Hair on head, eyebrows and eyelashes is filling in. Mom-to-be: You're showing more now, with an obvious swelling in your lower abdomen. A five- to 10-pound weight gain is typical by now. You also may be noticing an increase in appetite. Tip of the Week: Change positions slowly, especially when you move from a lying down position to sitting or from a sitting position to standing to avoid feeling dizzy or faint. If you feel lightheaded, sit down and lower your head, or lie down for a moment.

Week 18

Baby: Your baby measures 5 to 5.6 inches from crown to rump and weighs about 5.25 ounces, about the size of a yellow pepper. The rapid growth spurt is tapering off, but reflexes are kicking in. It can yawn, stretch and make facial expressions, even frown. Taste buds are beginning to develop and can distinguish sweet from bitter tastes. The baby will suck if its lips are stroked and it can swallow, and even get the hiccups. The retinas have become sensitive to light, so if a bright light is shined on your abdomen, baby will probably move to shield its eyes. Mom-to-be: Your uterus, about the size of a cantaloupe, can probably be felt just below your navel. You're most likely feeling the baby move by now. A mid-pregnancy ultrasound may be performed between now and 22 weeks to assess fetal growth and development and to verify the due date. If the baby is in the right position, the ultrasound may even be able to determine whether it's a boy or a girl. Your heart has to work 40 percent to 50 percent harder now to support your pregnancy.

Week 19

Baby: Your baby measures about 5.2 to 6 inches from crown to rump and weighs about 7 ounces, about the size of a tomato. Skin is developing and transparent, appearing red because blood vessels are visible through it. Creamy white protective coating, called vernix, begins to develop. Mom-to-be: As your baby continues to grow, you may be feeling some mid- pregnancy aches and pains by now -- lower abdominal achiness, dizziness, heartburn, constipation, leg cramps, mild swelling of ankles and feet, and a backache. Dilated blood vessels might cause tiny, temporary red marks on your face, shoulders and arms. Tip of the Week: Take care not to get overtired since rapid growth of the baby can compound the burden on your heart, lungs and kidneys.

Week 20

Baby: The fetus measures about 5.6 to 6.4 inches from crown to rump and weighs about 9 ounces, about the size of a banana. Your baby can hear sounds by now -- your voice, heart and your stomach growling, as well as sounds outside your body. It will cover its ears with its hands if a loud sound is made near you, and it may even become startled and "jump." The baby is moving often, too -- twisting, turning, wiggling, punching and kicking. Mom-to-be: Congratulations! You're at about the midpoint of your pregnancy. Your uterus is just about even with your navel. Your waistline has pretty much disappeared, but only temporarily! The risk of bladder infections increases because the smooth muscles in the urinary tract relax. Your breathing will become deeper and you may perspire more than usual from a more active thyroid gland.

STOP AND WATCH VIDEO AFTER WEEK 20. Week 21

Baby: Your baby measures about 7.2 inches from crown to rump and weighs about 10.5 ounces, about the size of a carrot. The fetus is steadily gaining fat to keep warm. Growth rate is slowing down but organ systems, like digestion, are continuing to mature. A waxy film, called the vernix caseosa, is being produced by your baby's oil glands and covers the skin to keep it supple in the amniotic fluid. Buds for permanent teeth are beginning to form. Mom-to-be: Friends, relatives, even strangers can probably tell you're pregnant by now. Your uterus is starting to extend above your navel. You've probably gained between 10 and 14 pounds by now.

Week 22

Baby: Your baby measures about 7.6 inches and weighs about 12.3 ounces, about the size of spaghetti squash. The muscles are getting stronger every week now, and the eyelids and eyebrows are developed. Your baby's acrobatics are pretty constant, and since he responds to sound, rhythm and melody, you can try singing and talking to him. After he's born, the same sounds will soothe him. Mom-to-be: Your uterus is continuing to grow, but you're probably feeling pretty good. Usually by now there is no more morning sickness, and your abdomen isn't so large that it's getting in the way very much. You may still be getting leg and foot cramps, as well as mild swelling of ankles and feet. To reduce cramping, increase your intake of calcium and potassium. Have a glass of milk before bedtime or snack on potassium-rich foods, such as grapefruits, oranges and bananas.

Week 23

Baby: Your baby is about 8 inches from crown to rump and weighs almost 1 pound, close to the size of a mango. The body is becoming proportioned more like a newborn, but skin is still wrinkled because your baby still has more weight to gain. Lanugo hair on the body sometimes turns darker. Mom-to-be: Your round belly is definitely noticeable by now. Weight gain will be about 12 to 15 pounds. You may still have aches in the small of your back. Lying down, massages and applying a heating pad or hot water bottle to the area can help.

Week 24

Baby: Your baby, now about in its 22nd week of development, is 8.4 inches from crown to rump and weighs about 1.2 pounds, about the size of an ear of corn. It is starting to produce white blood cells, mostly for combating disease and infection, and may respond to your touch or sounds. If you haven't felt hiccups yet, you might feel some jerking motion now. Mom-to-be: Your uterus is about 1.5 to 2 inches above your navel. Expect to gain about a pound per week this month. Glucose screens for detecting gestational diabetes are given between this week and 28 weeks. Dad-to-be might be able to hear the baby's heartbeat by putting his ear to your abdomen.

Week 25

Baby: Your developing baby now measures about 8.8 inches from crown to rump and weighs 1.5 pounds, roughly the size of rutabaga. Skin now becomes opaque instead of transparent. Its body is still covered with folds like a puppy dog that need to grow into its skin. Mom-to-be: Besides your uterus growing upward, it may be getting bigger on the sides of your abdomen. You may be experiencing hemorrhoids, which are dilated blood vessels in the rectal area caused by increased blood flow, constipation, indigestion and heartburn.

Week 26

Baby: Your baby measures about 9.2 inches from crown to rump and weighs almost 2 pounds now, about the size of a cucumber. Its hearing is fully developed. As the fetus reacts to sounds, its pulse increases. Your baby will even move in rhythm to music. Lungs are still growing but are not yet mature. Patterns of your baby's brain waves appear like a full-term newborn. It also has patterns of sleeping and waking. Mom-to-be: The baby's constant movements should be reassuring. You may be feeling some rib pain as your baby grows and pushes upward on your rib cage. The pressure may also be causing indigestion and heartburn. You may even be feeling stitch-like pains down the sides of your abdomen as your uterine muscle stretches.

Week 27

Baby: Your baby measures about 9.6 inches from crown to rump and weighs a little more than 2 pounds, about the size of a head of cauliflower. Hands are active and muscle coordination is such that he can get his thumb into his mouth. Thumb-sucking calms the baby and strengthens his cheek and jaw muscles. Your baby can cry now. Mom-to-be: You may see stretch marks as your uterus continues to expand. Most women have gained about 16 to 22 pounds by now. Balance and mobility also may be changing as you grow larger.

Week 28

Baby: Your baby measures about 10 inches from crown to rump, or a total length of about 15.75 inches from head to toe, and weighs about 2.4 pounds, close to the size of Chinese cabbage. Brain waves show rapid eye movement (REM) sleep, which means your baby may be dreaming. Eyelids are opening. Branches of lungs are developing, so there's a good chance that baby would survive if born prematurely now. Mom-to-be: As baby gets bigger and stronger this month, you may be experiencing leg cramps and mild swelling of ankles and feet, difficulty sleeping, shortness of breath, lower abdominal achiness, clumsiness or scattered Braxton Hicks contractions (hardening and relaxing of the uterus, like rehearsals for labor). You may also be urinating more frequently again as the uterus continues to push on your bladder. Week 29

Baby: Your baby measures about 10.4 inches from crown to rump, or a total length of about 16.7 inches from head to toe, and weighs about 2.7 pounds, about the size of butternut squash. At this stage a fetus's eyes are almost always blue and can distinguish bright sunlight or artificial light through the uterine wall. Baby is performing fewer acrobatics as conditions in the womb become more cramped, but still doing a lot of kicking and stretching. Mom-to-be: Your uterus is about 3.5 to 4 inches above your navel. Weight gain is probably between 19 and 25 pounds. If you do experience premature labor, your doctor often can stop labor from progressing with bed rest, muscle relaxants or other drugs, possibly requiring hospitalization.

Week 30

Baby: Your baby measures about 17 inches from head to toe and weighs about 3 pounds, about the size of large cabbage. Baby is growing plumper and beginning to control its own body temperature. Eyebrows and eyelashes are fully developed, and hair on the head is getting thicker. Head and body are now proportioned like a newborn's. Hands are now fully formed and fingernails are growing. Mom-to-be: Your uterus is about four inches above your navel, and it's hard to believe you still have about 10 weeks to go as baby continues to push on your ribs. You may be feeling more discomfort in your pelvis and abdomen.

Week 31

Baby: Your baby measures about 18 inches long from head to toe and weighs about 3.5 pounds, the size of four oranges. Rather than hearing vibrations, baby's nerve endings in his ears are connected now so that he can hear very distinct sounds, like familiar voices and music. Mom-to-be: Your uterus now fills a large part of your abdomen, and you've probably gained between 21 and 27 pounds. You're probably feeling increasing excitement and anxiousness about the birth -- it won't be long now. Week 32

Baby: Your baby measures about 18.9 inches long from head to toe and weighs almost 4 pounds, the size of jacamar. It fills almost all the space in your uterus now, either lying with the head up or sometimes still with enough room to do somersaults. A layer of fat is forming underneath the thin, wrinkly skin. Baby's practicing opening his eyes and breathing. Mom-to-be: Although you've only been seeing the doctor monthly, now you'll probably start seeing your practitioner every two weeks until the last month, when you'll probably switch to weekly visits. You may continue to get backaches and leg cramps.

Week 33

Baby: Your baby measures about 19.4 inches from head to toe and weighs about 4.4 pounds, the size of a pineapple. The next few weeks will mark lots of growth in the baby. The fetus will gain more than half its birth weight in the next seven weeks. Baby begins to move less now as it runs out of room and curls up with knees bent, chin resting on chest and arms and legs crossed. Mom-to-be: The uterus is about 5.2 inches above your navel, and you've gained between 22 and 28 pounds. Of the pound a week you're gaining now, roughly half is going to your baby. Tip of the Week: It's medically safe to continue having sex with your partner, but you may be too uncomfortable. Talk with your spouse about other ways to remain intimate, including backrubs and foot massages.

Week 34

Baby: Your baby measures about 19.8 inches from head to toe and weighs about 5 pounds, the size of cantaloupe. Baby is probably settling into the head-down position, although it might not be final. Organs are now almost fully mature, except for lungs, and the skin is pink instead of red. Fingernails reach the ends of fingers, but toenails are not yet fully grown. Baby might have lots of hair. Movements are less frequent because of the tight fit. Mom-to-be: Your pelvis has expanded and may ache, especially at the back. The uterus is pushed hard against your lower ribs and your rib cage may be sore, and your navel is probably pushing out as a result of your abdomen being stretched.

Week 35

Baby: Your baby measures about 20.25 inches from head to toe and weighs more than 5.5 pounds, the size of honeydew melon. Lungs are almost fully developed, but if born now the baby would probably be put in an incubator. It still doesn't have enough fat deposits beneath its skin to keep warm outside your womb. Mom-to-be: Your uterus is about six inches above your navel. By now your weight gain is probably between 24 and 29 pounds. You may be getting more uncomfortable and not sleeping very well. You also may be getting more anxious about the labor and delivery, and you may even be moodier and more irritable.

Week 36

Baby: Your baby measures about 20.7 inches from head to toe and weighs about 6 pounds, the size of Crenshaw melon. The baby may drop lower in your abdomen, usually assuming the head-down position after having frequently assumed other positions during early pregnancy. The brain has been developing rapidly, and your baby is practicing blinking. Mom-to-be: Your uterus has grown bigger these last few weeks and is probably up under your ribs. But you're in the home stretch; after this week you'll be seeing your doctor weekly. You may be alternating between fatigue and extra bursts of energy. You may also be experiencing increased backache and heaviness, constipation, heartburn and discomfort in your buttocks and pelvis.

Week 37

Baby: Your baby is about 21 inches from head to toe and weighs almost 6.5 pounds, around the size of a stalk of Swiss chard. Baby is getting rounder every day, and skin is getting pinker and losing its wrinkly appearance. Baby's head is usually positioned down into the pelvis by now. Mom-to-be: Your uterus may stay the same size as it was for the last week or two. Your weight gain should be about as high as it will go, about 25 to 35 pounds. About this time, your doctor might perform a pelvic exam to help judge the progress of your pregnancy.

Week 38

Baby: Your baby is about 21 inches from head to toe and weighs about 6.8 pounds and as long as a leek. Most of the baby's downy hair, lanugo, and whitish coating, vernix, is disappearing. Your baby is getting its antibodies from you to protect against illness. Baby's growth is slowing, but fat cells under skin get plumper for life outside the womb. Almost ready for birth, your baby would do well if born now.

Mom-to-be: You're probably not getting any bigger, but you may be feeling more uncomfortable. Make sure you have a bag packed. It won't be long now -- 95% of all babies are born within two weeks of their mother's due date.

Week 39

Baby: Your baby is about 21.5 inches long from head to toe and weighs a little more than 7 pounds, the size of a mini watermelon. Toenails and fingernails have grown to tips of toes and fingers. Muscles of your baby's arms and legs are strong, and he's practicing lung movements. Baby's head has dropped into the mother's pelvis if he's head-down, which allows you to breathe a little easier. Mom-to-be: You're probably feeling quite large and uncomfortable. Your uterus has filled your pelvis and most of your abdomen, pushing everything else out of the way. Your center of gravity has shifted, so you may be clumsier than usual. Week 40

Baby: Your baby's length is about 21.5 inches from head to toe and it weighs about 7.5 pounds, the size of a pumpkin. Boys often tend to weigh a little more than girls. Reflexes are coordinated so the baby can blink, close his eyes, turn his head, grasp firmly and respond to sounds, light and touch. More lanugo falls out, but some may remain at birth on shoulders, folds of skin and backs of ears. Mom-to-be: Birth should be soon now, but don't worry if your due date comes and goes. Only 5% of all babies are born exactly on the due date. It may be more difficult for you to get a good night's sleep because it's hard to find a comfortable position, but try to rest as much as possible, with your feet up if you can.