The first trimester of pregnancy can be overwhelming. Understand the changes you might experience and how to take care of yourself during this exciting time.
During the first few months of pregnancy, amazing changes happen quickly. This part of pregnancy is called the first trimester. Knowing what physical and emotional changes to expect can help you face the months ahead with confidence.
The second trimester of pregnancy is often the most enjoyable. Find out how to relieve common symptoms — and consider ways to prepare for what's ahead.
The second trimester of pregnancy often brings a renewed sense of well-being. The worst of the nausea often is gone. And the baby isn't big enough to cause too much discomfort. Also, this is the trimester when you may feel the baby move.
The third trimester of pregnancy can be a challenge for the body and the mind. Here's help easing symptoms and anxiety as your due date approaches.
The final 12 weeks of a full-term pregnancy are known as the third trimester of pregnancy. The third trimester can be full of excitement. It also may challenge your body and mind.
Fetal development starts soon after conception. Find out how your baby grows and develops during the first trimester.
Highlights of fetal development during the second trimester may include finding out your baby's sex and feeling the baby move.
Fetal development continues in the third trimester of pregnancy. During these final weeks, babies gain more weight and prepare for delivery.
You’re pregnant. Congratulations! As your pregnancy goes on, you may wonder how your baby is growing and developing. Use this information to follow along with what’s happening week by week during the first 12 weeks of pregnancy, called the first trimester.
It might seem odd, but you're actually not pregnant the first week or two of what's counted as your pregnancy's 40 weeks. Conception typically happens about two weeks after the last period begins. But to find your estimated due date, your healthcare professional counts ahead 40 weeks from the start of your last period. That means the period is counted as part of your pregnancy timeline even though you weren't pregnant at the time.
The sperm and egg unite in one of the fallopian tubes to form a one-celled entity called a zygote. If more than one egg is released and fertilized, or if the fertilized egg splits into two, the result may be multiple zygotes and a twin pregnancy.
The zygote typically has 46 chromosomes. That includes 23 from each biological parent. The chromosomes help determine the baby's sex and physical traits.
Soon after fertilization, the zygote travels down the fallopian tube toward the uterus. At the same time, it begins dividing to form a cluster of cells called a morula. A morula looks like a tiny raspberry.
Once it reaches the uterus, the morula becomes what's called a blastocyst. The rapidly dividing ball of cells begins to burrow into the uterine lining. This process is called implantation.
Within the blastocyst, the inner group of cells will become the embryo. The outer layer will give rise to part of the placenta. The placenta nourishes the unborn baby throughout pregnancy.
The fifth week of pregnancy, or the third week after conception, the level of the pregnancy hormone human chorionic gonadotropin, also called HCG, quickly rises. That tells the ovaries to stop releasing eggs and make more of the hormones estrogen and progesterone. Higher levels of estrogen and progesterone stop the menstrual period and fuel growth of the placenta.
The embryo is now made of three layers. The top layer, called the ectoderm, will become the outer layer of skin, central and peripheral nervous systems, eyes, and inner ears
The heart and a primitive circulatory system will form in the middle layer of cells, called the mesoderm. This layer of cells also will serve as the foundation for the bones, ligaments, kidneys and much of the reproductive system.
The inner layer of cells, called the endoderm, is where the lungs and intestines will develop.
The sixth week of pregnancy, or four weeks after conception, the neural tube along your baby's back is closing. The brain and spinal cord develop from the neural tube. The heart and other organs also start to form.
Structures needed to form the eyes and ears develop. Small buds appear that will soon become arms. Your baby's body begins to take on a C-shaped curve.
Seven weeks into pregnancy, or five weeks after conception, your baby's brain and face are growing. Depressions that will give rise to nostrils become visible. The start of the eyes' retinas form.
Lower limb buds appear that will become legs. The arm buds now take the shape of paddles.
Eight weeks into your pregnancy, or six weeks after conception, your baby's leg buds take the shape of paddles. Fingers have begun to form. Small swellings outlining the future shell-shaped parts of the ears develop, and the eyes become noticeable. The upper lip and nose have formed. The trunk and neck begin to straighten.
By the end of this week, your baby might be about 1/2 inch (11 to 14 millimeters) long from the top of the head to the bottom of the tailbone. This measurement is called crown to rump.
In the ninth week of pregnancy, or seven weeks after conception, your baby's arms grow, and elbows appear. Toes are visible and eyelids form. The head is large, and it doesn't have a clearly formed chin.
By the end of this week, your baby might be a little less than 3/4 inch (16 to 18 millimeters) long from crown to rump.
By the 10th week of pregnancy, or eight weeks after conception, your baby's head has become rounder. And the elbows can now bend. Toes and fingers lose their webbing and become longer. The eyelids and the outer parts of the ears continue to develop.
At the 11th week of pregnancy, or the ninth week after conception, your baby now is called a fetus. At this point in pregnancy, the face is broad, the eyes widely separated, the eyelids fused, and the ears are set low on the side of the head. Buds for future teeth appear. Red blood cells are beginning to form in the liver. By the end of this week, the outer genitals start developing.
By now, your baby might measure about 2 inches (50 millimeters) long from crown to rump. Your baby may weigh about 1/3 ounce (8 grams).
Twelve weeks into your pregnancy, or 10 weeks after conception, your baby is sprouting fingernails. Your baby's face has taken on a more developed profile. The intestines are in the abdomen.
By now, your baby might be about 2 1/2 inches (61 millimeters) long from crown to rump and weigh about 1/2 ounce (14 grams).
As pregnancy moves into the second trimester, your baby may begin to seem more real. At four weeks of pregnancy, your baby was a cluster of cells. At 11 weeks, the unborn baby became a fetus. Now, the organs, nerves, and muscles are starting to work. Use this information to follow along with what’s happening week by week during the second trimester.
As you track your pregnancy, remember that to find your estimated due date, your healthcare professional counts ahead 40 weeks from the start of your last period. That means you’re actually not pregnant the first week or two of what’s counted as your pregnancy’s 40-week timeline.
Thirteen weeks into pregnancy, or 11 weeks after conception, bones start to harden in your baby's skeleton, especially in the skull and long bones of the arms and legs. The skin is thin and transparent. But soon it will start to get thicker.
Fourteen weeks into pregnancy, or 12 weeks after conception, your baby's neck has become more defined. And red blood cells are forming in the spleen. Your baby's sex likely will become clearer this week.
By now, your baby might be almost 3 1/2 inches (87 millimeters) long from the top of the head to the bottom of the tailbone, called crown to rump, and weigh about 1 1/2 ounces (45 grams).
Fifteen weeks into your pregnancy, or 13 weeks after conception, your baby is growing quickly. Bone development continues. Soon you'll be able to see bones on ultrasound images. Your baby's scalp hair pattern also is forming.
Sixteen weeks into pregnancy, or 14 weeks after conception, your baby's head is upright. The eyes can move slowly, and the ears are close to reaching their final position. The skin is getting thicker.
Limb movements are becoming coordinated and can be seen during ultrasound exams. But those movements likely are too small for you to feel.
By now, your baby might be about 4 3/4 inches (120 millimeters) long from crown to rump and weigh about 4 ounces (110 grams).
Seventeen weeks into your pregnancy, or 15 weeks after conception, toenails start developing.
Your baby is becoming more active, rolling and flipping. Although you might not be able to feel those movements yet, you may feel your baby hiccuping, which causes small jerking movements.
Eighteen weeks into pregnancy, or 16 weeks after conception, your baby's ears start to stand out on the head. Your baby also might begin to hear sounds. The digestive system has started working.
By now, your baby might be about 5 1/2 inches (140 millimeters) long from crown to rump and weigh 7 ounces (200 grams).
Nineteen weeks into your pregnancy, or 17 weeks after conception, growth slows.
A greasy, cheeselike coating called vernix caseosa starts to cover your baby. The vernix caseosa helps protect your baby's delicate skin from scrapes, chapping, and hardening that can happen from being in contact with amniotic fluid.
Your baby also is starting to release urine that now makes up most of the amniotic fluid.
Halfway into your pregnancy, or 18 weeks after conception, you might be able to feel your baby's movements. This sometimes is called quickening. Your baby is regularly sleeping and waking and might be wakened by noises or your movements.
By now, your baby might be about 6 1/3 inches (160 millimeters) long from crown to rump and weigh about 11 ounces (320 grams).
Twenty-one weeks into pregnancy, or 19 weeks after conception, your baby is completely covered with a fine, downy hair called lanugo. The lanugo helps hold the vernix caseosa on the skin.
The sucking reflex also is developing, so your baby may be able to suck a thumb.
Twenty-two weeks into pregnancy, or 20 weeks after conception, your baby's eyebrows and hair are visible.
In the male reproductive system, the testes have begun to move down into the scrotum. In the female reproductive system, the uterus and ovaries are in place, and the vagina is developed.
By now, your baby might be about 7 1/2 inches (190 millimeters) long from crown to rump and weigh about 1 pound (460 grams).
Twenty-three weeks into your pregnancy, or 21 weeks after conception, your baby starts to have rapid eye movements. Ridges also form in the palms of the hands and soles of the feet that will create the foundation for fingerprints and footprints.
The lungs are starting to make a substance called surfactant. It allows the air sacs in the lungs to inflate and keeps the lungs from collapsing and sticking together when they deflate.
Twenty-four weeks into pregnancy, or 22 weeks after conception, your baby's skin is wrinkled and see-through. The skin tends to have a pink or red tint due to blood moving through the blood vessels.
By now, your baby might be about 8 1/4 inches (210 millimeters) long from crown to rump and weigh more than 1 1/3 pounds (630 grams).
Twenty-five weeks into your pregnancy, or 23 weeks after conception, your baby might move in response to familiar sounds, such as your voice.
At this point, your baby spends most sleep time in rapid eye movement. That's when the eyes move quickly even though the eyelids are closed.
By 26 weeks into your pregnancy, or 24 weeks after conception, eyebrows and eyelashes have formed. Your baby's eyes also are developed, but they may not open for another two weeks.
By now, your baby might be 9 inches (230 millimeters) long from crown to rump and weigh nearly 2 pounds (820 grams).
This week marks the end of the second trimester. At 27 weeks, or 25 weeks after conception, your baby's nervous system is continuing to mature. Your baby also is gaining fat, which helps the skin look smoother. This fat gain will continue into the third trimester.
The end of your pregnancy is near! By now, you’re likely eager to meet your baby face to face. But there’s still a lot happening to the baby, called a fetus, during the last weeks of pregnancy. Use this information to follow along with what’s going on during the third trimester week by week.
As you track your pregnancy, remember that to find your estimated due date, your healthcare professional counts ahead 40 weeks from the start of your last period. That means you’re actually not pregnant the first week or two of what’s counted as your pregnancy’s 40-week timeline.
Twenty-eight weeks into pregnancy, or 26 weeks after conception, your baby's eyelids can partially open. The central nervous system can control body temperature. It also can trigger breathing movements, which can be seen on an ultrasound.
By now, your baby might be nearly 10 inches (250 millimeters) long from the top of the head to the bottom of the tailbone, called crown to rump, and weigh about 2 1/4 pounds (1,000 grams).
Twenty-nine weeks into your pregnancy, or 27 weeks after conception, your baby can kick, stretch and make grasping movements.
Thirty weeks into pregnancy, or 28 weeks after conception, your baby's eyes can open wide. Your baby might have a good head of hair by this week. Red blood cells form in the bone marrow.
By now, your baby might be more than 10 1/2 inches (270 millimeters) long from crown to rump and weigh nearly 3 pounds (1,300 grams).
Thirty-one weeks into pregnancy, or 29 weeks after conception, your baby has finished most major development. Now it's time to gain weight quickly.
Thirty-two weeks into your pregnancy, or 30 weeks after conception, your baby's toenails are visible.
The layer of soft, downy hair that has covered your baby's skin for the past few months, called lanugo, starts to fall off.
By now, your baby might be 11 inches (280 millimeters) long from crown to rump and weigh about 3 3/4 pounds (1,700 grams).
Thirty-three weeks into pregnancy, or 31 weeks after conception, your baby's pupils can change size in response to light. Bones are hardening, but the skull still is flexible and soft.
Thirty-four weeks into your pregnancy, or 32 weeks after conception, your baby's fingernails have reached the fingertips.
By now, your baby might be nearly 12 inches (300 millimeters) long from crown to rump and weigh more than 4 1/2 pounds (2,100 grams).
Thirty-five weeks into pregnancy, or 33 weeks after conception, your baby fills most of the space in the amniotic sac and has less room to move. But you'll probably still feel lots of stretches, rolls and wiggles.
Thirty-six weeks into pregnancy, or 34 weeks after conception, your baby's skin is becoming smooth as more fat is added under the skin. The limbs start to look chubby.
Most babies have turned head down by this point. If your baby isn't head down, your healthcare professional may talk with you about ways to move the baby in that direction. That's usually done around week 37.
Thirty-seven weeks into your pregnancy, or 35 weeks after conception, your baby can grasp things firmly.
To get ready for birth, your baby's head might start going down into your pelvis. At this point, your baby is considered early term.
Thirty-eight weeks into pregnancy, or 36 weeks after conception, the measurement around your baby's head and around the belly are about the same.
Your baby's toenails have reached the tips of the toes. At this point, most of the lanugo is gone.
By now, your baby might weigh about 6 1/2 pounds (2,900 grams). But size varies quite a bit. Some babies may weigh nearly 9 pounds (4,000 grams) or more by this point in pregnancy.
Thirty-nine weeks into your pregnancy, or 37 weeks after conception, your baby is considered full term.
The chest is getting larger. Fat is being added all over the body to keep your baby warm after birth.
Forty weeks into pregnancy, or 38 weeks after conception, your baby might have a crown-to-rump length of around 14 inches (360 millimeters) and weigh about 7 1/2 pounds (3,400 grams). But remember that healthy babies come in lots of sizes.
Don't be worried if your due date comes and goes with no signs of labor starting. The due date is simply an estimate of when your pregnancy will be 40 weeks along. It doesn't predict exactly when your baby will arrive. Many people give birth before or after their due dates.
Having a baby is an exciting time that often inspires women to make healthier lifestyle choices and, if needed, work toward a healthy body weight.
Pregnant women should eat a balanced diet.
Nutrition is about eating a healthy and balanced diet so your body gets the nutrients that it needs.
Most women should gain somewhere between 25 and 35 pounds (11 and 16 kilograms) during pregnancy.
For women who are thinking about getting pregnant, following a health care provider’s advice.
Prenatal care is the health care you get while you are pregnant.
Gestational diabetes is high blood sugar (glucose) that starts or is first diagnosed during pregnancy.
Gestational diabetes is high blood sugar (glucose) that starts or is first diagnosed during pregnancy.
Gestational diabetes is diabetes, defined by high blood sugar (glucose), that starts during pregnancy.
Gestational diabetes is diabetes, defined by high blood sugar (glucose), that starts during pregnancy.
Gestational diabetes is high blood sugar (glucose) that starts during pregnancy.
Gestational diabetes is high blood sugar (glucose) that starts during pregnancy.
During pregnancy, it is harder for a woman's immune system to fight infections.
During pregnancy, it is harder for a woman's immune system to fight infections.
Newborn head molding is an abnormal head shape that results from pressure on the baby’s head during childbirth.
Newborn head molding is an abnormal head shape that results from pressure on the baby’s head during childbirth.
Be aware of urgent maternal warning signs and symptoms during pregnancy and in the year after delivery.
Be aware of urgent maternal warning signs and symptoms during pregnancy and in the year after delivery.
If you have never given birth before, you may think you will just know when the time comes.
Childbirth is the process of giving birth to a baby.
Most women will remain in the hospital for about 24 hours after vaginal delivery.
Each pregnancy and delivery is different, and problems may arise.
Labor that begins before week 37 is called "preterm" or "premature."
A premature infant is a baby born before 37 full weeks of gestation (more than 3 weeks before the due date).
Your baby is staying in the hospital NICU. NICU stands for neonatal intensive care unit.
Premature babies need to receive good nutrition so they grow at a rate close to that of babies still inside the womb.
A C-section is the delivery of a baby by making an opening in the mother's lower belly area.
You are going home after a C-section. You should expect to need help caring for yourself and your newborn.
If you had a cesarean birth (C-section) before, it does not mean that you will have to deliver the same way again.
Right now, you are focused on caring for your new baby. But new mothers must take special care of their bodies after giving birth and while breastfeeding, too.
Postpartum depression is moderate to severe depression in a woman after she has given birth. It may occur soon after delivery or up to a year later.
Menopause is a stage in life when you no longer can get pregnant.
A birth defect is a problem that happens while a baby is developing in the mother's body. Most birth defects happen during the first 3 months of pregnancy.
Down syndrome is a genetic condition in which a person has 47 chromosomes instead of the usual 46.
Spina bifida is a birth disorder in which the spine doesn’t fully develop.
Cleft lip and palate are birth defects that affect the upper lip and the roof of the mouth.
Cleft lip and cleft palate repair is surgery to fix birth defects of the upper lip and palate (roof of the mouth).
Congenital heart defects (CHDs) are problems with the structure of the heart. "Congenital" means that that the problems are present at birth.
Clubfoot is a condition that involves both the foot and lower leg in which the foot turns inward and downward. It is a congenital condition, which means it is present at birth.
Clubfoot repair is surgery to correct a birth defect of the foot and ankle.
Sickle cell disease (SCD) is a group of inherited red blood cell disorders. If you have SCD, there is a problem with your hemoglobin.
A miscarriage is the spontaneous loss of a fetus before the 20th week of pregnancy.
A threatened miscarriage is a condition that indicates the potential for a miscarriage.
Pregnancy after miscarriage can be stressful and confusing. When is the best time to get pregnant?
If you lose a fetus at or after the 20th week of pregnancy, it’s called a stillbirth.
A stillbirth is when a baby dies in the womb during the last 20 weeks of pregnancy.
