This week‑by‑week pregnancy calendar shows you some of the important developments taking place as your baby grows.

At this point in the pregnancy, all vital organs have been formed and are starting to work together. Congenital abnormalities are unlikely to develop after week 10.

If you saw a picture of your baby now, you'd think you had a genius on your hands — the baby's head accounts for about half of the body length!

Tiny fingernails and toenails start to form this week, which is the last of your first trimester.

As you begin the second trimester, your baby may be able to put a thumb in his or her mouth although the sucking muscles aren't completely developed yet.

Some fine hairs, called lanugo, have developed on your baby's face. This soft colorless hair protects the skin and will eventually cover most of your baby's body until it is shed just before delivery.

Muscle development continues, and your baby is probably making lots of movements with his or her head, mouth, arms, wrists, hands, legs, and feet.

Your baby can hold his or her head erect, and facial muscles now allow for a variety of expressions, such as squinting and frowning.

Your baby is still very tiny at about 5.1 inches from crown to rump this week.

Your baby's bones had been developing but were still soft. This week, they begin to harden, or ossify.

A waxy substance called vernix caseosa is covering your baby to help protect the delicate skin from becoming chapped or scratched.

You're now halfway through your pregnancy and possibly feeling your baby's first movements, which may begin between weeks 18 and 20.

Your baby's intestines are developed enough that small amounts of sugars are absorbed from the fluid your baby swallows and passed through the digestive system to the large bowel.

Brain and nerve endings are formed enough so that the fetus can feel touch, while you might be feeling irregular, painless Braxton Hicks contractions.

You may feel more forceful movements — your baby's daily workout routine includes moving the muscles in the fingers, toes, arms, and legs.

Your baby's inner ear has developed enough that your baby can know when he or she is upside down or right side up in your belly.

You may notice that your baby has resting and alert periods. Your baby's hearing has continued to develop, too — he or she may now be able to hear your voice!

Your baby now weighs a little less than 2 pounds and will gain weight steadily until birth.

This first week of the third trimester, your baby looks similar to what he or she will look like at birth - just smaller and thinner.

Your health care provider may tell you whether your baby is headfirst or feet- or bottom-first (called breech position). Don't worry if your baby is in the breech position right now — most babies will switch positions on their own.

Your active baby's first few flutters of movement have given way to hard jabs and kicks that may take your breath away.

Your baby continues to gain weight and layers of fat that will provide warmth after birth.

By now, the milk glands in your breasts may have started to make colostrum, the milk that will feed the baby in the first few days if you decide to breastfeed.

At this stage in the pregnancy, your baby's hair is developing, in the form of eyelashes, eyebrows, and on your baby's head.

Like a newborn, your baby sleeps much of the time and even has REM sleep, the stage when our most vivid dreams happen.

Your baby is probably in position for delivery — your health care provider can tell you if your baby is positioned head- or bottom-first.

Because of increasing size, your baby is now cramped and restricted inside the uterus. Fetal movements may decrease, but feel stronger and more forceful.

At this point, your appetite may return because the baby has dropped down into your pelvis, and is no longer putting as much pressure on your stomach and intestines.

This week, your baby continues to gain weight — at half an ounce a day!

At this point, you may be taking frequent trips to the bathroom. That's because your baby is engaged in your pelvis, so your bladder is extremely compressed.

Braxton Hicks contractions (also called "false labor") may become more pronounced, and your water may break.

During this week, your baby, or embryo, has two layers of cells that will develop into organs and body parts.

Your baby is here! Or maybe not — most women, especially first-time moms, don't deliver on their estimated due dates.

The umbilical cord has formed, and the mouth, nostrils, ears, and eyes are some of the facial features that become more defined this week. The arm bud now has a hand on the end of it, which looks like a tiny paddle.

Around this time, symptoms such as a missed period, nausea, extreme fatigue, or tight clothes may make the reality of pregnancy hit home.

Your baby measures about 0.6 to 0.7 inches from crown to rump and weighs around 0.1 ounces. Your baby may make some first movements as muscles develop, but you won't feel them for several more weeks.

Here's how to tell the difference between true labor and false labor -- and when to get medical care.

Where you choose to give birth is an important decision. Is a hospital or a birth center right for you? Knowing the facts can help you make your decision.

Choking is an emergency - so it's important to recognize the signs of choking and know what to do if happens.

When you first meet your newborn, you may be surprised by what you see. Here's what to expect.

Some women choose to give birth using no medications at all, relying instead on relaxation techniques and controlled breathing for pain. Get more information on natural childbirth.

During childbirth, a brachial plexus injury can happen if the baby's neck is stretched to one side.

Your baby's here! Find out what to expect on that special day first day of life.

Some women are more likely than others to go into labor early. Find out what doctors can do to help prevent or delay early labor.

Your tot's not a baby anymore! It's time for a big-kid booster seat. But how can you ensure that your child is still safe and secure in the car? Find out here.

Here are answers to some common questions about breastfed babies and sleep - from where they should snooze to when they'll finally start sleeping through the night.

Whether your baby comes home from the hospital right away, arrives later, or comes through an adoption agency, homecoming is a major event.

Find out what the experts have to say.

What's the right way to install an infant safety seat? Is your toddler ready for a convertible seat? Get the car seat know-how you need here.

Choking is an emergency - so it's important to recognize the signs of choking and know what to do if happens.

You have an important decision to make before you take your newborn son home: whether to circumcise him. Before deciding, talk to your doctor and consider the issues.

Colic is common in babies - but that doesn't make it easier for parents to handle. Learn what colic is, what causes it, and what you can do about it.

From birth, your newborn has been communicating with you. Crying may seem like a foreign language, but soon you'll know what your baby needs - a diaper change, a feeding, or your touch.

Constipation is a very common problem among kids, and it usually occurs because a child's diet doesn't include enough fluids and fiber. In most cases, simple changes can help kids go.

This harmless condition - the infant form of dandruff - causes rough, scaly patches on a baby's skin.

Diaper rash is a very common infection that can cause a baby's skin to become sore, red, scaly, and tender. In most cases, it clears up with simple changes in diapering.

Babies may use up to 10 diapers a day! Get the basics on how to diaper like a pro.

Find answers to common inquiries about introducing solids and whole milk to formula-fed babies.

Doctors use growth charts to figure out whether kids' height and weight measurements are "normal" and whether they're developing on track. Here are some facts about growth charts.

Find out what the experts have to say.

Find out what the experts have to say.

Find out what the experts have to say.

Once a baby arrives, it can seem as if the laundry doubles! Many parents think they need to use baby detergent to clean their baby's clothes, but in most cases, this isn't necessary.

When you first meet your newborn, you may be surprised by what you see. Here's what to expect.

You probably have lots of questions about your baby's health. When should you call the doctor, and what medical care should you expect for your baby at this age?

Because your baby begins to show his or her personality during these months, your questions may move from simple sleeping and eating concerns to those about physical and social development.

By the time you hold your new baby for the first time, you've probably chosen your little one's doctor. Learn about your newborn's medical care.

It may seem like all babies do is sleep, eat, and cry, but their little bodies are making many movements, some of which are reflexes.

Newborn screening tests look for health conditions that aren't apparent at birth. Find out which tests are done.

If you're a new mom, breastfeeding your baby can feel like a challenge. Check out this article for information on common nursing positions, proper latching-on techniques, and how to know if your baby is getting enough to eat.

Oral thrush, a very common infection in infants that causes irritation in and around the baby's mouth, often goes away on its own without medical treatment.

Considering adoption? Here are some things to know about the health and medical care of an adopted child, before, during, and after the adoption.

Newborn babies don’t yet have a sense of day and night. They wake often to eat – no matter what time it is.

Transitioning a baby from a bottle to a cup isn't always easy, as babies can become attached to their bottles. These tips can help parents make the switch.

Building a relationship with your child's doctor requires communication and reasonable expectations.

Teething can be a tough time for babies and parents. Here are the facts on teething, including tips for baby teeth hygiene and relieving pain.

Your baby's here! Find out what to expect on that special day first day of life.

Cutting your little one's nails can be a bit scary. Here's how to do it safely.

Weaning is when children make the transition from breast milk to other sources of nourishment. Here's how to make this change easier on you and your child.

The Apgar score is the very first test given to a newborn, done right after birth in the delivery or birthing room.

During the first 3 months of life, babies cry more than at any other time. Here's how to soothe them.

Why do newborns need a dose of vitamin K at birth? Find out what the experts have to say.

Find out what this doctor's checkup will involve a few days after your baby is born.

Find out what this doctor's checkup will involve after your baby arrives.

Immunizations protect kids from many dangerous diseases. Find out what vaccines your child needs to grow up healthy.

Your newborn is taking in first sights, sounds, and smells while learning to explore the world through the senses. What are your baby's responses to light, noise, and touch?

Colic is defined as crying for more than 3 hours a day, for more than 3 days a week, for at least 3 weeks.

Abusive head trauma is the leading cause of death in child abuse cases in the United States. It happens when someone shakes an infant.

Birthmarks that babies are born with, or develop soon after birth, are mostly harmless and many even go away on their own, but sometimes they're associated with certain health problems.

A cleft lip is when a baby's lip doesn't form properly during pregnancy. Most kids can have surgery to repair one early in life.

A cleft palate is when a baby is born with a cleft (gap) in the roof of the mouth. Most kids can have surgery to repair them early in life.

A cleft palate with a cleft lip is when a baby's lip and palate (roof of mouth) don't form properly during pregnancy. Most kids with cleft lip and palate are treated successfully with no lasting problems.

Colic is common in babies - but that doesn't make it easier for parents to handle. Learn what colic is, what causes it, and what you can do about it.

A baby with congenital cataracts has clouding in one or both eyes. Doctors do surgery to treat them.

Some babies are born with a thyroid gland that didn't develop correctly or doesn't work as it should. This is called congenital hypothyroidism.

Constipation is a very common problem among kids, and it usually occurs because a child's diet doesn't include enough fluids and fiber. In most cases, simple changes can help kids go.

This harmless condition - the infant form of dandruff - causes rough, scaly patches on a baby's skin.

Craniosynostosis is when seams between bones in the skull close too soon. When this happens, the skull can’t expand grow as it should, and it develops an unusual shape.

Diaper rash is a very common infection that can cause a baby's skin to become sore, red, scaly, and tender. In most cases, it clears up with simple changes in diapering.

Ebstein anomaly is a rare heart defect that affects the tricuspid valve. It can cause problems that range from very mild to very serious.

Febrile seizures are full-body convulsions caused by high fevers that affect young kids. Although they can be frightening, they usually stop on their own and don't cause any other health problems.

A fetal abdominal cyst is a bubble of fluid in a balloon-like bag in the belly of an unborn baby.

A fetal lung mass is an unusual lump that grows inside or next to an unborn baby’s lung. Some are treated before birth, while others are removed after the baby is born.

Babies can develop a flat spot on the back of their heads, usually from sleeping in the same position too long. Alternating your baby's sleep position and providing lots of "tummy time" can help.

Some babies are born with the metabolic disorder glactosemia. They must drink soy-based formula instead of breast milk or a cow's milk-based formula.

Goldenhar syndrome can cause incomplete development of bones in the face, affecting the ear, nose, soft palate, lip, and jaw. A cleft and craniofacial care team can help kids born with the condition.

Babies with this condition have trouble turning their heads, due to muscle tightness. Simple stretching exercises and physical therapy can help babies get better.

Malrotation is a type of obstruction caused by abnormal development of the intestines while a fetus is in the womb. Find out more about this condition and the complications it can cause.

Intussusception is the most common cause of bowel blockages in very young children. Quick treatment can help them recover without lasting problems.

Laryngomalacia is a common cause of noisy breathing in infants.

Maple syrup urine disease (MSUD) is a rare metabolic disorder that some babies are born with.

You probably have lots of questions about your baby's health. When should you call the doctor, and what medical care should you expect for your baby at this age?

Because your baby begins to show his or her personality during these months, your questions may move from simple sleeping and eating concerns to those about physical and social development.

Some babies are born with a meningocele, which is a sac that pushes through the gap in the spine. With surgery to fix the problem, most babies with a meningocele live a healthy, normal life.

Myelomeningocele is a type of spina bifida in which a baby is born with a gap in the bones of the spine.

During childbirth, a brachial plexus injury can happen if the baby's neck is stretched to one side.

If your child is allergic to nuts or peanuts, it's essential to learn what foods might contain them and how to avoid them.

A baby born with an omphalocele has an opening where the umbilical cord goes into the belly. Some openings close on their own, but many need treatment, including surgery.

Oral thrush, a very common infection in infants that causes irritation in and around the baby's mouth, often goes away on its own without medical treatment.

A cleft is when tissues of the mouth or lip don't form properly when a baby is developing in the womb. The good news is that orofacial clefts are treatable.

Phenylketonuria (PKU) is a metabolic disorder caused by a defect in the enzyme that breaks down an amino acid. PKU is treatable when it is found early.

For most kids, these birthmarks are no big deal — they're just part of who they are. Read about port-wine stains, how to care for them, and, if necessary, what treatments are available.

Gastroschisis is when a baby is born with the intestines, and sometimes other organs, sticking out through a hole in the belly wall near the umbilical cord. A gastroschisis silo allow the intestines to slowly move into the belly.

Sepsis is a serious infection usually caused when bacteria make toxins that cause the immune system to attack the body's own organs and tissues.

In spina bifida occulta, a baby is born with a gap in the spine's bones, but the spinal cord and its covering do not push through it.

Teething can be a tough time for babies and parents. Here are the facts on teething, including tips for baby teeth hygiene and relieving pain.

For some newborns, the first few breaths of life may be faster and more labored than normal because of a lung condition called transient tachypnea of the newborn (TTN).

An umbilical hernia shows up as a bump under the belly button. If a hernia doesn't go away by age 4 or 5 or causes problems, doctors may recommend surgery.

Learn what a NICU visit will be like for your little one, what you can do to help, and how to find support for yourself.

Find out what the experts have to say.

Find out what the experts have to say.

Find out what the experts have to say.

Find out what the experts have to say.

Find out what the experts have to say.

This recipe is especially for pregnant and breastfeeding women, but can be a nutritious part of almost anyone's diet.

This recipe is especially for pregnant and breastfeeding women, but it can be a nutritious part of almost anyone's diet.

Find out what the experts have to say.

Expecting another child? Things will be a little different this time. Here's how to prepare for your new addition.

Where you choose to give birth is an important decision. Is a hospital or a birth center right for you? Knowing the facts can help you make your decision.

Your tot's not a baby anymore! It's time for a big-kid booster seat. But how can you ensure that your child is still safe and secure in the car? Find out here.

What's the right way to install an infant safety seat? Is your toddler ready for a convertible seat? Get the car seat know-how you need here.

You might think of babies and toddlers when you hear the words "babyproofing" or "childproofing," but unintentional injury is the leading cause of death in kids 14 and under.

Choosing baby products can be confusing, but one consideration must never be compromised: your little one's safety.

Baby bathtubs give parents a safe way to wash a wet, slippery baby. Here's how to choose and use one.

Babies love and need close contact, and infant carriers are ideal for nestling them against their parents. Here's how to use one safely.

Babies can get hurt if they fall off changing tables, so they should always be watched closely. Here's what else to know.

When you choose a crib, check it carefully to make sure that your baby's sleep space is safe. Here's how.

Gates placed at the top of stairs or in doorways are used to keep toddlers away from hazardous areas of the home. Here's what to look for.

Regular infant seats simply allow young babies to sit up. Never substitute any type of infant seat for a child safety seat (car seat).

Playpens are popular because parents can put their baby in one knowing that their little one can't wander off. But they're no substitute for adult supervision.

Strollers come in a variety of sizes and styles. When you're searching for that perfect stroller that's light and portable, keep safety in mind.

All toys you select for your baby or toddler should meet safety standards. These tips can help you find safe toys for your little one.

More kids are injured in auto collisions than in any other type of accident, but you can protect them by learning the proper use of car seats and booster seats.

Newborn screening tests look for health conditions that aren't apparent at birth. Find out which tests are done.

Parents of twins (or more!) can feel as if they've left the hospital and arrived home on a different planet. Here's how to cope.

Find out what tests may be offered to you during the first trimester of pregnancy.

Find out what tests may be offered to you during weeks 27 through 40 of pregnancy.

If your daughter is pregnant and planning to have the baby, many changes await your family. How can you support her through the challenges to come?

It's best for babies not to be born before they're due. Learn what you can do to prevent early labor.

A fetal echocardiogram (also called a fetal echo) uses sound waves to create pictures of an unborn baby's heart.

Fetal magnetic resonance imaging (also called a fetal MRI) uses a magnetic field and radio waves to create detailed pictures of an unborn baby.

Newborn screening tests look for health conditions that aren't apparent at birth. Find out which tests are done.

This test takes a sample of the amniotic fluid. In the second trimester, it can show signs of chromosomal disorders, genetic problems, and neural tube defects. In the third trimester, it can check for infection and Rh incompatibility, and reveal if a baby's lungs are strong enough to breathe normall

A contraction stress test measures the fetal heart rate to ensure that a baby can handle contractions during labor.

The first trimester screening (or first trimester screen) includes a blood test and an ultrasound exam. It's done to see if a fetus is at risk for a chromosomal abnormality or birth defect.

Glucose screenings check for gestational diabetes, a short-term form of diabetes that some women develop during pregnancy.

This test checks to see if the baby responds normally to stimulation and is getting enough oxygen. It's done to check on the health of the fetus in a high-risk pregnancy or when the due date has passed.

This quick test examines fetal blood directly from the umbilical cord. It's used to detect disorders in the fetus.

Find out what tests may be offered to you during the first trimester of pregnancy.

Find out what tests may be offered to you during weeks 27 through 40 of pregnancy.

Some women are more likely than others to go into labor early. Find out what doctors can do to help prevent or delay early labor.

If your daughter is pregnant and planning to have the baby, many changes await your family. How can you support her through the challenges to come?