For women who engage in high-risk activities, such as intravenous drug use or unprotected sexual contact that can contribute to HIV or hepatitis B infection, it is highly advised that these women test for these infections during the third trimester of their pregnancies. Further, it is highly recommended (in fact, required in some states) to test or repeat the tests for sexually transmitted diseases such as syphilis, gonorrhea, and chlamydia in the third trimester.
A non-stress test (NST) may also be given to pregnant women. This is a non-invasive test performed after the 28th week to monitor health and look for indications of distress in high-risk pregnancies or babies past due. The test also measures the fetal heart rate concerning movement.
When healthcare practitioners are concerned about how contractions affect fetal heart rate, what is known as a contraction stress test may be performed following the stress test. The process involves medication given to the woman to induce mild contractions (stress). Then, the heart rate of the fetus is monitored.
Urine Screen for Glucose or Protein
The expectant mother may be asked to provide a urine specimen at each prenatal visit throughout the first, second and third trimesters. Urine testing is typically conducted in the office using a dipstick when screening for glucose (sugar) or protein. Small levels of protein and glucose are normal in urine. However, high levels can represent a problem and may require further testing.
High levels of protein in urine could mean that there is kidney damage or disease. It could also mean that there is a transient elevation. This could be due to:
- Emotional stress
- Physical stress
The additional tests needed to determine the cause include a complete urinalysis, a 24-hour urine protein test, and urine culture (to identify any present yeast
present or any bacteria).
During the second and third trimesters, one particularly concerning condition, is preeclampsia (also known as toxemia or pregnancy-induced hypertension), which involves high blood pressure and excessive amounts of protein in the urine. It occurs in about eight percent of all pregnancies, and the symptoms include:
- Weight gain
- Vision changes
The risk factors for preeclampsia include:
- Being pregnant with more than one child
- Women over the age of 40
- African Americans
- Having diabetes
- Having kidney disease
- Having hypertension
Preeclampsia can reduce air and nutrition getting to the infant through the placenta, which causes low birth weight or other serious issues. However, if preeclampsia is caught early enough by regularly checking urine protein levels and blood pressure, serious health problems can be managed for both the mother and the baby.
A sign of undiagnosed diabetes existing in a mother could be high urine glucose levels. Gestational diabetes, which is a type of diabetes that can occur during pregnancy, is another sign. After a positive urine test for glucose, a confirmatory blood glucose test is typically conducted. A confirmatory blood glucose test is also routinely used to screen during the second trimester (24 to 28 weeks of pregnancy) for gestational diabetes.
A Urine Culture, Used to Decide Bacteria in the Urine (First-time or Repeated.)
Many organizations recommend pregnant women get screened for asymptomatic bacteriuria using a urine culture between 12 to 16 weeks gestation or at the first prenatal visit. These organizations include:
- The American College of Obstetricians and Gynecologists (ACOG)
- The United States Preventative Services Task Force (USPSTF)
- The Infectious Diseases Society of America (IDSA)
- The American Academy of Family Physicians (AAFP)
It should be noted that the ACOG recommends the screening at the first prenatal visit and then repeated in the third trimester if you are relying on information from this specific organization.
When large amounts of bacteria are found in a urine culture during pregnancy, it's known as asymptomatic bacteriuria. A woman with this condition will not experience any associated urinary tract infection, such as pain or urgency to urinate. Approximately 2 to 10 percent of American pregnant women have this condition. Asymptomatic bacteriuria can lead to severe kidney infections and increase the risk of low birth weight and preterm delivery. It is advised that women suffering from asymptomatic bacteriuria seek appropriate antibiotic treatment.
Group B Strep Screen
Group B streptococcus (GBS) is a common bacteria present as a part of the normal vagina flora and gastrointestinal areas of about 25 percent of women. Group B streptococcus (GBS) is not like Group A streptococcus, which causes strep throat.
Group B streptococcus is not usually a problem unless it is present in the vagina during delivery. If the bacteria is present during delivery, the infection can spread to:
- · The uterus
- · The urinary tract
- · The amniotic fluid
- · The incision made during a cesarean
As the baby passes through the mother's birth canal during delivery, the baby can inhale or ingest the group B strep bacteria.
Within six hours of birth or as late as two months of age, the infant will display symptoms if an infant is infected. If left untreated, an infant can:
- · Become septic
- · Develop pneumonia
- · Develop physician disabilities
- · Develop learning disabilities
- · Suffer hearing and vision loss
To determine the risk of a pregnant woman infecting her infant at delivery, the U.S. Centers for Disease Control and Prevention (CDC) recommends screening pregnant women for GBS between 35 to 37 weeks of gestation. To determine if Group B strep bacteria are present, within 24 to 48 hours, samples of the mother's vaginal and rectal areas are collected. If it is found that the bacteria is present, or if the mother goes into labor before testing is complete, it is recommended that the mother get antibiotics intravenously during her delivery.
Throughout a woman's pregnancy, GBS bacteria can come and go. Therefore, it is not helpful to test for GBS early in the pregnancy. Testing at that time will not determine if it is present during labor or if it could spread to the baby during delivery. Testing late in the pregnancy (35 to 37 weeks) is what is useful for accuracy—also, treating with oral antibiotics before labor is not proven to stop GBS infections in newborns.
Complete Blood Count (First-time or Repeated)
A complete blood count (CBC) tests the cells circulating in the blood. There are three kinds of cells suspended in plasma that blood consists of white blood cells (WBCs), red blood cells (RBCs), and platelets (PLTs). A CBC can be done before pregnancy, in the beginning, or one or more times during pregnancy to identify and stop problems. After baseline values are established from initial testing, results from follow-up testing can be compared to them to check for any changes that could indicate a health issue.
Red Blood Cells
When a woman is pregnant, her hemoglobin must be able to supply enough oxygen to both her and her fetus. Hemoglobin is the oxygen-carrying protein found in red blood cells
. Hemoglobin binds to oxygen in the lungs, spreads it throughout the body, and gives it to cells and tissues. A woman with insufficient red blood cells or hemoglobin is anemic.
Lots of pregnant women will have some degree of anemia. Mild anemia can cause tiredness and weakness. But severe anemia in a pregnant woman can cause the fetus not to receive enough oxygen for normal development.
During delivery, every woman loses a small amount of blood. This is typically not a problem, but even small amounts of blood loss can be dangerous to an anemic woman. Therefore, healthcare practitioners might want to determine the hemoglobin level in a pregnant woman's blood before delivering, which will assess the possible impact of the expected blood loss.
White blood cells
The purpose of white blood cells is to protect the body from infection and serve other immune functions. When a woman's white blood cells are involuted during pregnancy, it can help determine infections to treat and resolve before significant health problems occur for the mother or her baby.
Special cell fragments in the blood are called platelets. They help to form clots to stop bleeding. Women who have low platelet counts or improperly functioning platelets are at risk of life-threatening bleeding during delivery. If a platelet count problem is identified, follow-up testing may be needed to create treatment options.
Thyroid Stimulating Hormone if a Female Has Thyroid Disease History
When a woman is pregnant, regular changes occur in the functioning of the many endocrine glands. However, it has a definite effect on the thyroid gland. The thyroid gland produces hormones, such as triiodothyronine (T3) and thyroxine (T4), essential to the mother's health and healthy fetus development
If a female has thyroid conditions, she requires careful monitoring if she becomes pregnant. A healthcare practitioner may conduct tests for thyroid-stimulating hormone (TSH) to monitor a woman's thyroid function throughout her pregnancy. The pituitary, a small gland in the brain, creates TSH and responds to low T3 or T4 levels. If a woman is taking thyroid hormone replacement medication but still shows increased TSH levels, it may mean that the dose needs to be increased.
It is advisable to screen women before pregnancy or during the first trimester for elevated TSH, even if there is no history of thyroid disease. A large percentage of women may have an underlying thyroid disorder that can cause issues during pregnancy.
RBC Antibody Screen
There are several blood types:
Each blood type can also be Rh positive or negative.
Every pregnant woman should know her blood type. [See Blood Typing for more information.] Both mother and child may experience problems if their blood types are not the same or if the mother is Rh-negative and the fetus is Rh-positive, resulting in a severe condition known as Hemolytic Disease of the Newborn (HDN).
The woman's immune system can create an Rh antibody that attaches to the Rh-positive antigens on her baby's red blood cells and sets them up for destruction. The first Rh-positive baby is not likely to become ill. However, the antibodies produced will affect future Rh-positive babies.
An Rh-negative mother is less likely to develop this antibody if given the routine Rh immune globulin injection (rhogam) at about 28 weeks gestation. In addition, injections could be necessary during her pregnancy if she has chorionic villus sampling, amniocentesis, or an abdominal injury. Also, injections could be required after delivery if the baby is Rh-positive. Before a woman receives an injection, a screen for antibodies is done to ensure Rh antibodies are not already present.
In addition, women who have had blood transfusions or had prior pregnancies could create an antibody to blood factors other than Rh that has the potential of harming an unborn baby. Getting an antibody screen during a woman's first trimester can determine if potentially harmful antibodies are present in the mother's blood. When a harmful antibody is present, if possible, the baby's father should be tested. This will determine if the father's blood has antigens that react with the mother's antibody. If there's a reaction, the fetus may also have the same antigens as the father. If the antibody reacts with the fetus', a healthcare practitioner should evaluate the mother's antibody level and the fetus for the length of the pregnancy. If there are signs that the fetus is becoming ill, it could mean that treatment before birth (such as intrauterine transfusion) or early delivery is required.
Rh incompatibility has serious consequences. One of the most common causes of HDN is the incompatibility between the baby's ABO blood groups and the mother's. Therefore, you can't use the RBC antibody screen to see if HDN will occur because antibodies to the ABO blood groupings occur naturally.
Fetal Fibronectin (fFn) for a Woman With Preterm Labor
This test is given if a woman is between 22 to 25 weeks pregnant with premature labor symptoms to determine premature delivery risks. What is desired is an intervention to protect the preterm baby.
Vaginal fluid or a cervical sample is collected and analyzed for fFN, a glycoprotein located between the lining of the uterus and the amniotic sac. There can be high levels because of other causes other than the risk of preterm delivery. Thus, a positive fFn result is not entirely reliable for preterm labor and delivery. Nevertheless, a negative fFN is highly determinative that preterm delivery won't occur within 7 to 14 days. Risks are present when treating a woman for premature labor. A negative fFn can eliminate unnecessary hospitalizations and drug therapies.
Amniocentesis if Risk of Preterm Labor
While the procedure is conducted, a medical professional inserts a needle through the walls of the abdomen, uterus, and the thin-walled fluid sac surrounding the developing fetus. Amniotic fluid is withdrawn in a small amount. Inside the fluid is AFP created by the baby and fetal cells. A medical professional can test these fetal cells for genetic or chromosomal abnormalities. Based on family history, a gene analysis may be performed to check for the possibility of the child being born with a birth defect or hemoglobinopathy. Or research on the results of screening tests done on the parents (for cystic fibrosis, for example
.). To complete the testing, approximately two weeks are needed.
A slight risk exists with amniocentesis in this situation. The needle inserted into the amniotic sac could puncture the baby, which would cause a small amount of amniotic fluid leakage, an infection, or in rare situations, even a miscarriage could result in the pregnancy.