There is nothing boring about pregnancy. It’s an exciting and nerve-racking journey of change. From conception to delivery, the developing mother-to-be and the baby will experience extensive transformations.
Most people refer to a pregnancy length as nine months. In fact, a full-term pregnancy usually lasts closer to 10 months or 40 weeks, and these weeks branch into three trimesters. From week-to-week, there are amazing events happening inside a pregnant woman’s body. Embryos and fetuses follow similar patterns, and these changes are universal during a healthy pregnancy.
The development of the baby can be easier understood when using fruit and vegetable comparisons. When thinking of a grape, an apple, or a pumpkin, it’s easy to get the sense of the approximate weight and the length of the developing baby. When the question, “How far along?” comes up, the answer “A bell pepper,” is clear and totally relatable.
Within 10 months, a baby-to-be will transform from the size of a tiny seed to the size of a pumpkin. With each passing week, a baby in utero gradually develops into a tiny human, but using our progress chart will provide a better idea of just what each week entails.
Plus, frequent ultrasounds are not recommended during pregnancy, so our chart provides a picture of just how the baby is changing. Examining how the little one transforms is also a reminder of the awesome miracle that is growing within mom-to-be.
There are telltale signs to determine that a woman may be expecting a child before taking an official test. One indication of pregnancy is a missed menstrual period. Other signs are nausea, sore breasts, and frequent urination. Fatigue can also start as early as one week into the pregnancy. It’s partially caused by an increase in the hormone progesterone.
Many women choose to test for pregnancy with home tests first because they are fast, convenient, relatively inexpensive, and 97 percent accurate. Urine tests can detect pregnancy about one to two weeks after conception. A blood test should also be taken as blood tests are more sensitive than urine tests. If a pregnancy test or a pelvic exam reveals a baby is on the way, this marks the beginning of the first trimester.
The baby will develop quickly within the first month. The amniotic sac will surround the fertilized egg to protect it throughout the pregnancy. The placenta develops to transport nourishment from the bloodstream to the baby. The baby’s mouth, throat, blood cells, and circulation begin to develop. By week four, the baby—technically an embryo—is about 2 millimeters long. If an expecting mother is one-month pregnant, her baby is about the size of a tiny seed, such as a strawberry seed.
Womb, there it is! There’s a little person in there. Now that the baby is on board, it’s time to start prenatal care to ensure the safety of the developing child. For example, prenatal vitamins will be prescribed as multivitamins help a developing baby receive nutrients that are essential for healthy growth. This is one important reason to confirm a pregnancy as soon as possible because the first few weeks are a delicate time for the baby.
Next, the expecting parents will need to find out when the little one will arrive. The due date is an educated guess of when the mother-to-be will spontaneously go into labor. The calculation is pretty simple if she has made note of the date of her last menstrual period or the conception date. But, the most accurate way to determine the due date is based on the size of the fetus during the first ultrasound.
Although the baby is only about the size of a sweet pea or a lentil, an expanding uterus, and the increasing baby weight add constant pressure to the bladder and the urethra, causing urinary stress. This is why frequent urination is one of the first signs of pregnancy, starting in the first trimester around week six.
By the 7th or 8th week, the pregnancy starts to become noticeable, and the baby evolves rapidly. The baby’s brain, spinal cord, eye folds, nose, heart, and lungs are developing. The heartbeat is audible. The baby’s fingers and toes are webbed.
Reproductive organs have not yet developed, but this is the time that a gene will trigger the development of the either the testes or the ovaries. By week seven, the baby is about the size of a kidney bean.
This is also the time when the mother-to-be may start to feel pregnant. Hormone levels will change, so she may be affected mood swings. Her breasts will swell because her milk ducts are growing. These weeks are especially vulnerable to the development of the baby.
Illicit and legal substances, viruses, and toxic substances, such as pesticides, can cause birth defects, so taking care of the baby means taking care of the mother.
By week 9 of the pregnancy, the baby is moving around, but the mom-to-be won’t be able to feel it. Besides being more active, the baby begins to swallow and develop reflexes. Nails, teeth, and reproductive organs are forming. The web between the fingers and toes goes away. By week 10, the embryo becomes a fetus, and the tail goes disappears. This is the stage when the baby is about the size of a grape.
The expecting mother continues to evolve as well. Not every pregnant woman experiences severe nausea, but 80 percent report moments of queasiness in the first trimester. The term “morning sickness” is a bit of a misnomer. Yes, nausea commonly occurs at the crack of dawn, but it can repeat all day long. So, 2 ½ months in, moments of nausea are probable.
Some women see relief within the second trimester, but others don’t have it so lucky, feeling ill effects all throughout pregnancy. Women usually don’t gain much weight in the first three months, but this may be the stage where women actually lose weight.
By week 11, the baby resembles a shrimp. By week 12, the baby is fully formed, measuring about the size of a lime. And, parents-to-be will be excited to hear a strong heartbeat during the routine checkup.
In the third month of pregnancy, women should also have their first ultrasound. This scan determines the baby’s age. Others screenings will test for birth defects.
Carrying a child is hard work that takes energy out of a woman’s body. Tiredness can start as early as week one, but by week 12, it’s common for expecting moms to suffer from chronic fatigue. Fortunately, as the bump grows, so does the motherly glow. A mom-to-be may notice an improvement in her hair and nails due to higher estrogen levels.
By the end of your first trimester, pregnant women should not be feeling as tired as they did in the previous month. Frequent trips to the bathroom and nausea should also subside.
Although an expecting mother will not yet be able to feel her baby’s kicks, the baby’s limbs are flailing. Around week 14, the baby weighs about 43 grams and measures roughly about the size of a lemon. The increased weight is partially due to the formation of the sex organs. In fact, an ultrasound may be capable of determining the baby’s gender at this stage.
While the baby’s genital formation is underway, changes continue to occur with the expecting mom. This is the stage where pregnant women experience a growth spurt. Women may start to gain weight rapidly from here on end.
On the inside and out, the breasts are becoming larger. The milk glands of the breasts engage when a woman becomes pregnant, which is why many women notice a significant enlargement in cup size as early as the first trimester. But because some moms-to-be respond early in pregnancy, some women can even start to leak a thick, yellowish liquid from their breasts in the second trimester. This liquid is known as colostrum.
Welcome to the second trimester! Month four is an exciting stage for an expecting mother. It’s when she may start to feel the baby kick or at least move slightly. If she feels movement, she should make note of the date to tell her doctor. Kicking can help determine the due date. By 15 weeks, the baby weighs about four ounces and is relatively about the size of an apple.
The ultrasound technician will definitely be able to identify reproductive organs and tell parents-to-be the gender of your baby. The roof of the baby’s mouth and the hair starts to develop. The baby’s fingers are defined, and thumb sucking is possible. Eyebrows and eyelashes are formed. The intestines are coming into place.
At this stage, an expanding waistline is probably making the pregnancy obvious. Expecting moms usually start to wear maternity clothes in the 4th month to feel more comfortable. A visible bump is an instant ice breaker, so she’ll need to be prepared for an infinite supply of advice here on end. A pregnant woman is a walking magnet for unsolicited advice, and generally, this is the stage where the world of motherhood opens up to the public.
Most pregnant women feel their babies move around the 17th week. After this time, the future baby can communicate through taps, rolls, and kicks. The expecting mother may even feel the baby’s hiccups. But most likely, the infant will become active when the mother is still. At 18 weeks, the baby is 7 ounces and 5 ½ inches long, and roughly about the size of a bell pepper.
Researchers have found that by the 18th week of pregnancy, babies in utero can hear, and they can be affected by the outside world. Of course, babies do not hear like humans in the outside world. The ears are filled with fluid, and the mother’s abdominal tissue limits audible information.
There are constant heartbeats, liquids are moving, and the mother’s stomach growls, so the womb is a noisy place to live. In that environment, everyone sounds like Charlie Brown’s teacher. Despite the muffled words, there is much information that can be deciphered. The infant may change positions or pokes the mom’s belly when she speaks. Dads can affect the baby, too, by talking close to mom’s bump.
Congratulations, parents-to-be! The halfway mark of the pregnancy has arrived. During this month, the baby will grow tremendously. With strength comes more activity in the womb, and regular jabs from the uterus will be a thing. This is known as quickening.
Not only will the baby be moving, but the little one will be quite active, especially when the expecting mother lays down to rest. Still, the fetal movement may only be noticed by experienced mothers. First-timers may not feel the tiny kicks for weeks to come.
By week 20, the developing baby is about the size of a banana from the head to the bottom and weighs about 0.5 lbs. Vernix caseosa covers the skin; this is a greasy, white substance that covers a baby’s skin at birth. Lanugo also starts to form; this is a fine hair grown on the shoulders and the back. The baby’s hair is also sprouting on the head and in the eyebrow region.
By 21 weeks, the little one weighs about ¾ lbs. Measuring 10 ½ inches long, the baby is as long as a carrot from head to heel. This carrot-sized cutie is the reason mothers will really notice their pregnant bodies expanding. At this stage, expecting women gain about 5-15 lbs, and develop breasts two cup sizes larger.
The mother-to-be will also notice an increase in fetal movement. Some babies kick less often and some kick more, but every baby has an individual pattern of activeness. Even if there are no obvious problems, the obstetrician will want the expecting mom to make note of fetal movements. She will be asked to keep track of the number of times the baby stirs within a specific time. She will also be asked to keep track of how long 10 movements take.
The activity can also depend on the day, but less than normal movement should be brought to the attention of the obstetrician or midwife.
Rapid growth continues in month six for both the mother-to-be and the baby. In this stage, the little one is almost fully formed and resembles a tiny human being. At over 11 inches long, a mango is a good description of the relative size and length of the baby.
At this stage, the baby weighs over 1 lb. The baby’s taste buds develop. The veins show through the baby’s almost see-through skin. Babies can survive under intensive care if born after 23 weeks. From this point on, the mom-to-be will gain about 1 lb a week. At the next screening, the doctor will perform a test for gestational diabetes.
In the 6th month, an expecting mom is noticeably pregnant, and her body will be working overtime to provide for the baby. Her heart and lungs will work 50 percent harder. Unfortunately, because of the baby’s weight, she may experience a shortness of breath, and a pain in her rib cage. It’s amazing that a baby the size of a mango can produce all of these effects.
From head to heel, the little one now measures 13 ½ inches long. The baby weighs as much as an average rutabaga at 1 ½ lbs. At this stage, the baby’s hearing is well-developed and will acknowledge external sounds. When the infant is at 25 weeks gestation, the little one can identify the voice of her mother, and echo the rhythm of the mother’s voice with movement. Just speak, then wait for a reaction.
Scientific evidence shows that the stimulation of reading enhances the infant’s intellectual development. Naturally, the baby-to-be won’t comprehend words, but listening to a voice will ignite an enthusiasm for sounds, and help cultivate listening skills.
What’s truly amazing is that babies in their third trimester remembered the stories they were read, up to a month after birth. While a regular dose of Dr. Suess may not create a famous writer, the baby will notice and remember when he or she listens to the story again after birth.
Welcome to the third trimester! The mom-to-be will probably notice stretch marks on her thighs and her abdomen. Also, her belly button will pop out soon enough if it hasn’t already. This growth at 27 weeks can be attributed to the baby who weighs between 2-4 lbs, rivaling the head of a cauliflower in weight.
At this stage of pregnancy, some women feel Braxton Hicks contractions. These are non-productive contractions that are generally painless. The reason they occur is to give your uterus a dry run for labor.
Unfortunately, 75 percent of soon-to-be mothers also experience lower back pain. Pregnancy back pain is the result of hormonal changes that soften and thin out ligaments, joints, and muscles to prepare for dilation during labor. Plus, weight gain causes an expecting mother’s center of gravity to shift.
To compensate for the baby’s growing weight in the uterus, a pregnant woman has a tendency to push her weight forward, creating an arch at the base of the spine. Poor sleeping positions can further strain the back. Chronic pain can plague a pregnancy, but if the expecting mother is receiving an adequate supply of calcium, this condition should be less of a problem.
The baby is now the average size of a large cabbage. Tipping the scales at 2 ½ lbs and measuring 15 inches long from head to heel, the little one begins to fill all of the wrinkly crevices of the body as fat deposits grow under the baby’s skin.
Aside from the physical transformations, the baby will begin a routine of waking and sleeping cycles. A nap may occur for 30-90 minutes, followed by an active session of kicks and jabs.
For the mom-to-be, puffy feet and swollen ankles are common in the third trimester of pregnancy. Again, hormonal changes are a factor. To boot, expecting women retain more water and carry extra weight. All of these elements put a burden on the veins, which reduces blood flow back to the heart.
As a result, the legs, ankles, and feet can balloon. The swelling can be uncomfortable, but it often disappears after childbirth.
Around this time, the baby will gain about 0.5 lbs from now until birth. The belly of the mom-to-be may look bigger than a coconut, but that is roughly the size of the baby. At 3 ¾ lbs and almost 16 ¾ inches in length, the baby begins to crowd the uterus.
The development of the sense of taste actually begins in utero. At 32 weeks gestation, babies can taste the fluid flowing through the amniotic sac. The tastes and flavors are not nearly as concentrated for the baby because the mother has the added sense of smell. The baby will still get a taste and even begin to identify certain foods.
In fact, studies show an expectant mother can literally shape her baby’s tastes from the food and drinks she consumes during pregnancy.
Research also shows that infants are born with only one taste bud. The taste receptors for sweet develop during pregnancy and are present at birth. It’s no wonder why babies prefer milk to all other food.
Mom-to-be is in the home stretch now. Start packing the hospital bag because the baby is almost here. At 34 weeks pregnancy, the baby weighs about 4 ¾ lbs. From head to heels, the pineapple-sized preemie measures almost 18 inches long.
At this stage, the baby’s brain develops quickly. Lanugo starts to shed from the skin. The internal organs are completely developed, except the lungs are still immature. The baby may hiccup, and the future mom may notice the baby kicking more often.
For the future mom, it’s common to feel tired and anxious for labor. It’s also common for women at this pregnancy stage to have difficulty sleeping. The increasing weight and the fetal activity of the baby often keep her up at night. Unfortunately, women may also urinate a little while sneezing, laughing, or coughing because of the pressure of the baby’s weight rests on the bladder.
Plus, the center of gravity is probably making mom-to-be feel a little off kilter. Practicing good posture will not only protect her balance, but it will also help with body aches.
The parents-to-be are now down to the wire. After months of waiting, the baby will soon be born. Without a doubt, preparing for a baby requires more than Pampers and paint. It also requires a great deal of patience.
By week 36, the baby weighs almost 6 lbs. The not-so-little baby is comparable to the size of a honeydew melon, measuring over 18 ½ inches long. That’s also about the size as a head of romaine lettuce. With only a few weeks to go, the womb becomes crowded, leaving the baby little room to maneuver. Hopefully, the baby is already positioned upside down in mom’s uterus so the little one is not in a breech presentation.
The final weeks of pregnancy are a thrilling yet nerve-wracking time for a soon-to-be mom. Sleep deprivation can set in, causing nervousness and anxiety. Physically, this is an uncomfortable time for pregnant women. Throughout 9 or 10 months, 35 pounds is the average weight gain, and this increasing weight causes body strains. The good news is that the pregnancy is ending.
It is common for pregnant women to give birth between week 39 and week 40, but the exact length varies. Mother Nature has her own schedule, but delivery usually happens within two weeks on either side of the due date, with twins and triplets arriving a little earlier. By week 40, the baby weighs about 7-8 lbs.
The baby’s lungs are just about developed. The pupils can dilate to adjust to the light. Lanugo and vernix caseosa are almost gone, but lanugo can linger on a newborn’s skin for a few months after birth. Also at this stage, the baby’s position will change as the head usually drops towards the pelvis. Nearing birth, the baby is about the size of a small pumpkin.
No pregnant woman escapes the clutches of unpleasant symptoms, such as heartburn, backaches, swollen feet, and mood swings. But sometimes, the hardest part of the pregnancy is the wait. While the delivery day approaches, mothers-to-be can do more than twiddle their thumbs.
Expecting moms should attend weekly prenatal appointments to check the vital signs of the babies. And, while waiting for labor to begin, they can practice breathing techniques. In the final stages of pregnancy, the key is to try to keep the worries at bay because, in no time, mom and dad will be holding a precious, little newborn baby in their arms.