Do you know how your nervous system works? This system coordinates all your body’s activities, and chances are it’s functioning normally during your pregnancy. In the rare case that it’s not, here’s what you need to know.

HIV can be passed to a child when he or she is in the mother's womb or as the infant passes through the birth canal. The virus has also been detected in breast milk.

Acute fatty liver of pregnancy is a rare, but serious, condition of pregnancy in which there is an excessive accumulation of fat in the liver or liver cells.

Alcohol consumption by the mother is a leading cause of preventable birth defects in the fetus. In addition, the risk for miscarriage and stillbirth increases with alcohol consumption.

Alpha-fetoprotein screening is a blood test that measures the level of AFP in the mothers' blood. Abnormal levels may indicate certain problems with the fetus.

Detailed information on amniocentesis, including potential risks and benefits

Too much or too little amniotic fluid around the fetus can cause problems. These include preterm labor, birth defects, and underdeveloped lungs in the fetus.

Doctor appointments and baby showers aren’t the only things that can tucker you out when you’re pregnant. Anemia is a condition that also can make you feel fatigued. Find out what you need to know to safeguard yourself.

This disease can have serious effects in pregnancy, both for the mother and the baby. These include strokes, blood clots, and recurrent miscarriage.

With proper asthma management and good prenatal care, most women with asthma can have healthy pregnancies.

Detailed information on autoimmune diseases and pregnancy

A biophysical profile is a test that combines a nonstress test with ultrasound. It's usually performed in the last trimester.

Bleeding may occur at various times in pregnancy. Although bleeding is alarming, it may or may not be a serious complication.

A woman with a multiple pregnancy needs more calories and nutrients, more frequent prenatal visits, and more rest.

Cholestasis of pregnancy is a condition in which the normal flow of bile in the gallbladder is slowed or stopped resulting in itching and jaundice.

Chorioamnionitis is an infection of the membranes and amniotic fluid. It occurs in about 1 to 2 percent of all pregnancies, but is much more common in preterm births.

Detailed information on chorionic villus sampling, including potential risks and benefits

When a woman has pre-existing hypertension or develops hypertension before the 20th week of pregnancy, this is called chronic hypertension.

Having more than one baby is especially exciting—and complicated. Find out what to watch for, including a greater chance of anemia and preterm birth.

It's important for a woman with diabetes to keep her blood sugar under tight control while she's pregnant.

Detailed information on digestive and liver disorders during pregnancy

Doppler flow is a type of ultrasound that measures the flow of blood through a blood vessel. Doppler flow studies may be used to assess blood flow in the umbilical blood vein and arteries, fetal brain, and fetal heart.

Ectopic pregnancies nearly always occur in the fallopian tube. Rarely, an ectopic pregnancy will be located in an ovary or in the cervix, or even in the abdomen.

Epilepsy and the medications to treat it can have affect the mother, the pregnancy, and the fetus and newborn. Fortunately, most women are able to have a healthy pregnancy and baby.

Fetal blood sampling is a procedure to remove a small amount of blood from the fetus during pregnancy. It may be taken to diagnose problems or an infection.

Detailed information on fetal monitoring, including potential risks and benefits

Fetal movement counting, often called kick counting, is a way a mother can help monitor the movements of her unborn baby by counting the number of kicks in a certain time period.

Screening during the first trimester is a combination of ultrasound and two blood tests. These tests can help determine the risk of certain birth defects.

Genetics is the study of the patterns of inheritance - how traits and characteristics are passed from parents to their children.

Gestational diabetes is a condition in which a pregnant woman has elevated glucose levels and other symptoms of diabetes—but did not have diabetes before she became pregnant.

Pregnancy-induced hypertension is also called toxemia or preeclampsia. It occurs most often in young women with a first pregnancy.

Glossary of terms relating to high-risk pregnancy

In pregnancy, blood volume increases greatly. This extra fluid puts an increased workload on the heart and may cause problems for a woman with heart disease.

HELLP syndrome is a serious complication of severe pregnancy-induced high blood pressure. It usually develops before delivery, but may also occur after delivery.

It is important that women avoid contracting herpes during pregnancy, because a first episode during pregnancy creates a greater risk of transmission to the newborn.

Detailed information on high-risk pregnancy

Vomiting—especially during the first trimester—is normal for many women during pregnancy. Constantly vomiting is not. Take action to prevent a serious complication.

Uncontrolled hyperthyroidism has many effects. It may lead to preterm birth and low birthweight. It may also bring on pregnancy-induced high bloo pressure.

Signs of an underactive thyroid gland (hypothyroidism) may be masked by pregnancy. But the thyroid is important for your baby’s brain development. Learn if you should be screened for hypothyroidism.

Almost every drug passes from the mother's bloodstream through the placenta to the fetus. Illicit substances that cause drug dependence and addiction in the mother also cause the fetus to become addicted.

Newborn babies with this condition often appear thin, pale, and have loose, dry skin. The umbilical cord is often thin and dull-looking rather than shiny and fat.

You’ve probably been warned not to eat brie cheese or order your steak cooked to anything less than medium. Why do you have to take these precautions? Listeriosis. Learn more about this food-borne illness and how to avoid it.

In pregnancy, infections are a common complication—but women may not have obvious symptoms, or they may show different symptoms of an infection.

Women with high-risk pregnancies often need a close watch for potential problems or complications. Many tests and procedures are available to monitor the health of both mother and baby.

With proper medical care, most women can enjoy a healthy pregnancy, despite medical challenges such as diabetes or high blood pressure.

All medications you take affect the fetus, depending on the stage of development, the type and dosage of the medication being taken, and your drug tolerance.

Many women experience migraine headaches while pregnant. The good news is that you don’t have to give in to the pain when it strikes. Know what pain-relief options are safest for you.

Ultrasound is usually used to diagnose miscarriage. If the fetus is no longer in the uterus, or there is no longer a fetal heartbeat, miscarriage is diagnosed.

Detailed information on multiple pregnancies, including care of multiple birth babies

Pregnancy does not appear to speed up the course or worsen the effects of MS. Some studies have found that MS symptoms decrease in pregnancy and increase after delivery.

Pregnant women with MG often have more weakness and fatigue because of the added weight and effort of pregnancy. Preterm labor (labor before 37 weeks of pregnancy) is more likely.

Detailed information on neurologic conditions in pregnancy

Because many multiples are small and born early, they may be initially cared for in a special care nursery called the neonatal intensive care unit.

Detailed information on nonstress testing

You need about 300 extra calories a day to maintain a healthy pregnancy. These calories should come from a balanced diet of protein, fruits, vegetables, and whole grains.

List of online resources to find additional information on high-risk pregnancies

A "birth defect" is a health problem or physical change that is present in a baby at the time he/she is born.

Multiple pregnancy is a pregnancy with two or more fetuses. In the United States, the multiple birth rate is rising.

Pregnancy loss occurs in more than half of early pregnancies. Most of these occur so early that the mother does not even know she is pregnant.

Planning ahead and taking care of yourself before becoming pregnant is the best thing you can do for you and your baby.

Postpartum hemorrhage is excessive bleeding after the birth of a baby. Most postpartum hemorrhage occurs right after delivery, but it can occur later as well.

Postpartum thyroiditis is a temporary but fairly common condition that results in either an overactive or underactive thyroid.

A pregnancy that lasts more than 42 weeks is considered post-term. Post-term pregnancy is associated with longer labors and the need for cesarean delivery.

Detailed information on preconception care

Detailed information on pregnancy and medical conditions

Detailed information on the most common complications during pregnancy

Detailed information on pregnancy loss, including types, causes, symptoms, diagnosis, and treatment

Many women today are waiting until later in life to have children. In the United States, birth rates for women in their 30s are at the highest levels in three decades.

Rupture of the membranes near the end of pregnancy may be caused by a natural weakening of the membranes or from the force of contractions.

Detailed information on prenatal diagnosis to detect fetal abnormalities in the womb

Preterm birth is the greatest problem associated with preterm labor. Although most babies are born after 37 weeks, those born preterm are at increased risks for many complications.

Rh disease occurs during pregnancy when there is an incompatibility between the blood types of the mother and baby.

Detailed information on identifying potential risks of a pregnancy as an important part of preconception care

Screening is usually performed by taking a sample of the mother's blood between the 15th and 20th weeks of pregnancy (16th to 18th is ideal).

Whether it’s your first or third trimester, you’re likely to face changes to your sleep habits while pregnant. Discover what it takes to feel rested no matter what stage you’re in.

Don't smoke during your pregnancy and limit how much time you spend in environments where there is secondhand smoke.

Stillbirth is a common term for death of a baby while still in the uterus. Common causes are high blood pressure or infection in the mother, or placental or cord problems.

Every pregnant woman feels like she’s getting big, but if you’re pregnant with two or more babies, you’ll really be growing fast. Be prepared by learning the signs of a multiple birth.

Lupus can affect pregnancy at any stage. It is not clear whether the severity of the disease or the type of medication causes problems.

Detailed anatomical information on the respiratory system in pregnancy

Detailed information on thyroid conditions and pregnancy

Detailed information on high-risk pregnancy

Toxoplasmosis is not only harmful to moms-to-be, but also to their unborn babies. If you haven’t heard of toxoplasmosis, you’ll definitely want to brush up on this new word.

Genetic diseases are classified by type: chromosomal abnormalities, single gene defects, problems caused by exposure to certain substances, or a combination of these.

Detailed information on ultrasound and the potential risks and benefits

During pregnancy, the kidney enlarges and the bladder is compressed by the growing uterus. These and other factors make it more likely for a woman to develop a urinary tract infection.