The Second Trimester of Pregnancy: Checkups & Tests Health Article

Prenatal Visits

Most women who are at low risk for pregnancy complications will see their health care provider every month during pregnancy, although they shouldn't hesitate to call with questions or concerns in between visits. On arrival at the office you will be asked to produce a urine sample. When a room becomes available, you will be escorted into it to wait for your provider. Remember that obstetricians have busy schedules and deliveries can be unpredictable, so you might want to bring a book or magazine in case you have to wait. You may be able to reschedule your appointment if there is a long delay. Check your provider's office policy for canceling appointments and rescheduling.

History

At each visit, your provider will want to know how you are feeling and if you have any particular concerns or issues. It is suggested that you compile a list of questions for your appointment. Your doctor would rather answer all of your questions during a scheduled visit than to have you call in the middle of the night. In addition, your provider will most likely ask you about fetal movement, sleep patterns, and symptoms of preterm labor and preeclampsia (hypertension along with excessive protein in the urine and edema).

Physical Examination

Your physical examination during each visit is usually brief. The nurse or assistant will measure your weight and take your blood pressure while you are sitting down.

Fundal Height

Your provider will measure the height of your uterus (the fundal height). This measurement is taken from the top of your pubic symphysis (pelvic bone) to the top of your uterus. From 20 weeks until 35 weeks there is generally a consistent relationship between the fundal height and the length of your pregnancy (for example, 20 centimeters (+ or - 2 cm) at 20 weeks, 30 centimeters (+ or - 2 cm) at 30 weeks, etc.). In certain circumstances, however, this measurement is not accurate (for example, in women who are obese, who have fibroids, who are carrying more than one fetus, or who have excess amniotic fluid).

Fetal Heartbeat

Your provider will also listen for the fetus' heart beat with a Doppler ultrasound. Doppler technology uses sound waves to measure the heart beat and is perfectly safe for you and the baby. A normal fetal heart rate is faster earlier in pregnancy than later, ranging from 120 to 160 beats per minute. During the examination, your provider will assess whether or not the heart rate is too fast or too slow. Occasionally it will be difficult to distinguish your heartbeat from that of the fetus. If there is any question about whose heart beat it is, your provider can take your pulse and simultaneously listen to the fetal heart rate. The two rates should be different.

Edema

Your provider will check your lower extremities for the presence of edema (swelling). Swelling in your legs is quite common in pregnancy, and it generally becomes more severe in the third trimester.

After obtaining your interval history and performing your physical examination, your provider will make the following types of assessments.

Is Your Fetus Growing Appropriately?

Your provider will use the increase in your uterine size as a marker for fetal growth. For example, at your 20-week visit your fundal height should measure around 20 centimeters. At your 24-week visit, your fundal height should measure around 24 centimeters. There is normal variance among the actual measurements, and a 2 or 3 cm difference is not generally a cause for concern. If your fundal height does not grow or is growing slower or faster than expected, your provider will probably order an ultrasound examination to evaluate the fetus and the amniotic fluid.

Are You Gaining an Appropriate Amount of Weight?

Generally, doctors tabulate how much weight you have gained compared to your prepregnancy weight. If you are gaining more than expected, you may need to limit your intake of fruit drinks and sweets. If this dietary change does not curb your weight gain, you may want to write down what and how much you are eating to help your provider evaluate your diet. Some women who gain an excessive amount of weight are not overeating, but are simply gaining water weight which is more easily lost after delivery.

If you are not gaining an appropriate amount of weight, you will need to supplement your diet. Your provider may recommend that you eat two or three healthy snacks a day in addition to what you've been eating. Again, writing down what you are eating will help your provider determine how best to ensure that you and your baby are well nourished. If the problem persists, you may want to consult a dietitian.

For more information on gaining weight during the second trimester, go to The Second Trimester of Pregnancy: Weight Gain & Other Changes

Is Your Blood Pressure ?

By the time you realize you're pregnant, your blood pressure will have already decreased. Blood pressure decreases during pregnancy in response to pregnancy hormones and changes in your blood volume. Blood pressure usually reaches its lowest value at 24 to 26 weeks' gestation. Your provider will watch to see whether your blood pressure has decreased in a predictable way and whether it has started to increase. Some women will have incredibly low blood pressures (for example, 80/40) in the second trimester. As long as you feel well, this is not a cause for concern.

You do need to be careful when you stand up abruptly from sitting or lying down. Your blood may be pooled in your lower extremities if your uterus has pressed on the blood vessels that drain your legs. When you stand up, you may feel faint because your body senses that not enough blood has reached the brain. Sit back down; when you are feeling better, stretch out your legs and slowly get up.

Do You Have Protein in Your Urine?

Each time you go to the office, your provider will check your urine for the presence of protein. It is normal to have 0-1+ protein on a urine test. Sometimes, your protein will be higher if you have a urinary tract infection. The greatest concern with protein in your urine is that you may be developing a condition of pregnancy called preeclampsia, which is hypertension along with edema and excessive protein in the urine.

Medications

Continue to take your multivitamins (for example, Prenate Advance) and iron pills (ferrous sulfate). Depending on your blood count, your doctor may have you take anywhere from one to three iron pills per day. If you are having heartburn, you can take calcium carbonate (Tums with calcium). This is effective treatment for heartburn and helps supply your body with calcium, but talk to your doctor before adding any supplement.

Testing During the Second Trimester

Triple Screen Test

In the second trimester, all women under the age of 35 should be offered a triple screen test (a blood test). Depending on the laboratory, this test may be called a variety of things, such as MSAFP, PACE, or multiple marker screening. The triple screen test may detect possible fetal abnormalities, such as spina bifida, Down's syndrome, and trisomy 18 syndrome.

Women Over 35 Years Old

The role of the triple screen test in patients over 35 years of age is controversial. At the present time the standard of care is to offer all women older than 35 prenatal diagnosis through amniocentesis or chorionic villus sampling, because the risk of fetal conditions is higher in older women. Amniocentesis and chorionic villus sampling gives a 100% detection rate for genetic abnormalities, but carries a 0.5% risk of complication. Screening the blood through the triple screen test lowers the detection rate to 85 to 90%, but it is not associated with the same complications as invasive methods. Ten to 15% of Down's syndrome cases are missed by the triple screen test. If you are older than 35, you should discuss your screening options with your doctor.

What is the Triple Screen Test?

The triple screen test checks the levels of maternal serum alpha-fetoprotein (MSAFP), unconjugated estradiol (UE3) and beta human chorionic gonadotrophin (beta-hCG) in the blood. Abnormal levels of these substances in the blood indicate increased risk for neural tube (which develops into the spinal cord and brain) defects, Down's syndrome, and trisomy 18. The triple screen test cannot diagnose any fetal disorder, it is simply a screening tool to identify women whose pregnancies are at increased risk.

What Conditions Are Associated with Abnormal Triple Screen Tests?

Both Down's syndrome and trisomy 18 are chromosomal abnormalities. Down's syndrome is characterized by an extra chromosome number 21, typical physical features, and mental retardation of varying severity. Trisomy 18 is marked by an extra chromosome number 18 which causes an essentially fatal condition. Advanced maternal age increases the risk for Down's syndrome, trisomy 18, and trisomy 13.

When Should I Have the Triple Screen Test?

The test must be offered between 15 and 22 weeks of gestation, depending on the lab used. The ideal time to do the test is at 16 to 18 weeks, because the detection rate is better.

What Percent of Patients Have Abnormal Results?

Five to 10% of patients will have an abnormal maternal serum screen. These patients should be informed and reassured that most positive tests are associated with normal fetuses. A positive test simply means higher risk for a complication and that further investigation should be considered.

What Happens If the Results Are Abnormal?

Falsely abnormal triple screening may be explained by wrong gestational age, multiple gestation (such as twins), vaginal bleeding in the first trimester, or fetal demise. If results are abnormal, these conditions are excluded before the evaluation for the condition at risk is undertaken.

An ultrasound is usually the first step in evaluating abnormal triple screen test results. Ultrasound can help rule out the possibility that incorrect gestational age, multiple gestation, or fetal demise caused the abnormal results.

Amniocentesis

Unlike the screen tests, amniocentesis can provide definitive diagnostic information but is associated with a 0.5% risk of complications. During this procedure, your doctor will get a sample of amniotic fluid by inserting a small needle through your skin and into the amniotic sac. The decision to accept or decline amniocentesis is a personal decision. An amniocentesis is an invasive procedure that carries a risk of losing the pregnancy and provides information that only you-not your physician-may use to make decisions or to alter the course of the pregnancy. You might make the decision to undergo amniocentesis according to the intended use of the information that would be made available by the procedure. For example, if knowledge of the fetal karyotype (chromosome characteristics) would not alter the course of the pregnancy, it may not benefit you to undergo amniocentesis. If, after consultation with your physician, it seems that the risk for a condition like Down's syndrome is great enough after ultrasound findings, then you may choose not to proceed with amniocentesis. It is important, however, to realize that ultrasound examination will not reduce the risk for chromosomal abnormalities to 0% because it doesn't analyze the fetal karyotype. For those patients wanting a definitive diagnosis of abnormality, amniocentesis for fetal chromosomal analysis is required.

Ultrasound

The use of ultrasound has become an essential tool for evaluation of the baby during pregnancy. Ultrasound bounces sound waves off your body tissues to create an image on a screen the same way a submarine uses sonar. More than half of all pregnant women in the United States undergo at least one ultrasound examination. No adverse effects have been confirmed from the use of ultrasound in humans at diagnostic levels of intensity. The current data indicate that the benefits to patients exposed to diagnostic levels of ultrasound outweigh the risks, if any, that may be present. The need for an ultrasound examination varies depending on factors complicating the pregnancy and the gestational age of the pregnancy.

A second trimester (approximately 13 to 27 weeks) ultrasound affords the advantage of providing reasonably accurate dating of the pregnancy (within 10 to 14 days) as well as allowing an assessment of the development of the fetal anatomy, location of the placenta, and evaluation of amniotic fluid. In a pregnancy without risk factors for complications and in which the first trimester pelvic exam is in agreement with menstrual dating, the initial ultrasound examination may be obtained in the second trimester to confirm dating by using the LMP (last menstrual period) and an assessment of fetal anatomy.

In the second trimester, structures in the fetus's head can be seen with some detail, and the palate, lips, orbits (eye sockets), stomach, four chambers of the heart, site of umbilical cord insertion, and the number of blood vessels in the umbilical cord, kidneys, bladder, and four extremities can be seen. Evaluation of the spine prior to 16 weeks may be less than optimal because of insufficient bone formation of the sacral spine prior to this gestational age. The two great vessels coming from the heart, the aorta and pulmonary artery, are more easily seen after 18 weeks. The amount of amniotic fluid, the number of fetuses, as well as the placenta can also be evaluated.

It is important to realize that there are limitations to prenatal diagnosis by fetal ultrasound. Some anatomical abnormalities are more readily detected prenatally than are others, while some abnormalities simply cannot be diagnosed prior to birth at all. If you are at increased risk for a having a fetus with a specific abnormality, then usually the physician reviewing the ultrasound with you will let you know if the abnormality lends itself to prenatal diagnosis. For example, hydrocephalus or "water on the brain" can usually be detected prenatally, if present. Small defects in the wall between the ventricles in the heart, however, often go undetected before birth.

Various factors influence the quality of the ultrasound image. A very thick maternal abdominal wall (for example, in obese women) is likely to reduce resolution significantly and may contribute to diagnostic errors. Furthermore, fetal position may render evaluation of certain structures impossible. In order to overcome these obstacles, the ultrasound technician may roll you from side to side and instruct you to drink plenty of fluids before the examination. Nonetheless, despite tremendous effort on the part of the examiner, obstacles to obtaining an adequate study often remain. The physician who reviews the results of the examination with you will comment on any limitations of the examination other than those inherent to ultrasound as an imaging study. It is important to realize that the finding of an anatomically normal fetus does not guarantee a normal and healthy baby since many conditions and diseases are not associated with anatomic abnormalities or birth defects at all.

Your doctor may decide to do an ultrasound in the second trimester if you are going to be age 35 or greater by the time of your due date or if you had an abnormal triple screen.

One-Hour Glucose Tolerance Test (Glucola)

The other test obtained in the second trimester is a Glucola or one-hour glucose tolerance test.

The American College of Obstetrics and Gynecologists (ACOG) recommends that all women be screened for gestational diabetes. Similar to the triple screen, this is a screening test and is not diagnostic. If your Glucola is abnormal (greater than 140 mg/dL), your provider will recommend that you have a three-hour glucose tolerance test in order to determine whether you have gestational diabetes. Some providers use a lower cut off on the screening test in order to ensure more women with gestational diabetes are diagnosed. The one-hour glucose tolerance test involves drinking a cup of a sugar solution (50 gm sugar) and having your blood drawn to check your glucose level (sugar level) after one hour. The sugar solutions come in different flavors. You do not need to do anything special to prepare for this test.

Other Tests

Depending on your obstetrical history, your provider may order another blood count, a platelet count, an RPR (rapid plasma reagin test, a test for syphilis), or screen for sexually transmitted diseases or bacterial vaginosis.

If you are an expectant father and would like more information about how you can prepare for the birth, go to The Second Trimester of Pregnancy: The Pregnant Father

If you would like more information about what to expect during your second trimester, go to The Second Trimester of Pregnancy: Mother.

If you would like to know what your baby is experiencing during the second trimester, go to The Second Trimester of Pregnancy: The Developing Baby

Go to The Second Trimester of Pregnancy: Concerns & Tips