Common Tests & Screenings During Pregnancy

Pregnancy is a time of profound transformation, both physically and emotionally, for expectant mothers. Amidst the excitement and anticipation of welcoming a new life into the world, there are important steps to take to ensure a healthy pregnancy journey. Central to this is the realm of prenatal care, which includes a series of tests and screenings designed to monitor both maternal and fetal health.

These tests serve as invaluable tools for healthcare providers to identify potential risks, detect abnormalities, and provide necessary interventions to safeguard the well-being of both the mother and the developing baby. From the initial confirmation of pregnancy to the final stages before delivery, a variety of screenings are recommended at different stages of gestation.

In this blog, we’ll explore the landscape of common tests and screenings during pregnancy, shedding light on their purposes, procedures, and significance in promoting a smooth and healthy pregnancy experience for expectant mothers worldwide. Whether you’re embarking on this journey for the first time or adding to your family, understanding these essential screenings will empower you to make informed decisions and actively participate in your prenatal care journey.

First Trimester

During the first trimester of pregnancy, several important tests and screenings are typically conducted to ensure the health and well-being of both the mother and the developing fetus. Let’s delve into each of these in detail:

Blood Tests: Blood tests are one of the initial steps in prenatal care, usually performed shortly after confirming pregnancy. These tests provide crucial information about the mother’s overall health and can help identify any underlying conditions that may affect the pregnancy. Some of the key components of blood tests during early pregnancy include:

Blood Type and Rh Factor: Determining the mother’s blood type (A, B, AB, or O) and Rh factor (positive or negative) is essential for assessing the risk of Rh incompatibility between the mother and the baby.
Complete Blood Count (CBC): This test measures various components of the blood, including red blood cells, white blood cells, and platelets. Anaemia, which can affect pregnancy outcomes, can be detected through CBC.
Blood Glucose Levels: Monitoring blood glucose levels is important for detecting gestational diabetes, a condition that can develop during pregnancy and affect both the mother and the baby.
Screening for Infectious Diseases: Blood tests may also screen for infectious diseases such as HIV, syphilis, and hepatitis B, as these can have implications for pregnancy and prenatal care.

Urinalysis: Urinalysis involves analyzing a urine sample to detect various indicators of health and potential complications. During pregnancy, urinalysis can provide important information about:

Urinary Tract Infections (UTIs): UTIs are relatively common during pregnancy and, if left untreated, can lead to more serious complications. Urinalysis can detect the presence of bacteria or other signs of infection.
Gestational Diabetes: Elevated levels of sugar in the urine may indicate gestational diabetes, a condition that requires careful management during pregnancy.
Preeclampsia: Protein in the urine can be a sign of preeclampsia, a serious condition characterised by high blood pressure and organ dysfunction that can develop in the latter half of pregnancy.

Ultrasound: An ultrasound scan is a non-invasive imaging technique that uses sound waves to create a picture of the developing fetus and the structures within the mother’s abdomen. During early pregnancy, ultrasound serves several important purposes:

Confirming Pregnancy: An ultrasound can confirm the presence of a gestational sac in the uterus, confirming the pregnancy and ruling out ectopic pregnancy (when the embryo implants outside the uterus).
Estimating Due Date: By measuring the size of the embryo or fetus, ultrasound can estimate the gestational age and due date.
Detecting Multiples: Ultrasound can identify the presence of multiple pregnancies (twins, triplets, etc.) by visualising multiple gestational sacs or embryos.
Assessing Viability: In cases of vaginal bleeding or other concerns, ultrasound can assess the viability of the pregnancy by evaluating fetal heartbeat and development.

Nuchal Translucency Screening: Nuchal translucency screening is a specialised ultrasound scan performed between 11 and 14 weeks of pregnancy. This test is used to assess the risk of chromosomal abnormalities, particularly Down syndrome (trisomy 21). During the screening, the thickness of the nuchal fold, a small pocket of fluid at the back of the baby’s neck, is measured. An increased thickness may indicate an elevated risk of chromosomal abnormalities, prompting further diagnostic testing such as chorionic villus sampling (CVS) or amniocentesis for confirmation.

Second Trimester

During the second trimester of pregnancy, additional tests and screenings are typically recommended to further assess the health and development of the fetus. These screenings aim to detect potential chromosomal abnormalities, genetic disorders, and structural anomalies. Let’s explore each of these in detail:

Maternal Serum Screening (Quad Screen): Maternal serum screening, also known as the quad screen, is a blood test conducted between weeks 15 and 20 of pregnancy. This test evaluates the levels of certain proteins and hormones in the mother’s blood to assess the risk of specific fetal abnormalities, including neural tube defects and chromosomal abnormalities such as Down syndrome (trisomy 21), Edwards syndrome (trisomy 18), and Patau syndrome (trisomy 13).
The quad screen typically measures the levels of four substances:

Alpha-fetoprotein (AFP)
Human chorionic gonadotropin (hCG)
Estriol
Inhibin A

Abnormal levels of these substances may indicate an increased risk of certain fetal abnormalities, prompting further diagnostic testing such as amniocentesis or chorionic villus sampling (CVS) for confirmation.

Amniocentesis: Amniocentesis is an invasive prenatal diagnostic procedure offered to women at increased risk of genetic disorders or chromosomal abnormalities. It is typically performed between weeks 15 and 20 of pregnancy. During the procedure, a thin needle is inserted through the abdomen into the amniotic sac to collect a small sample of amniotic fluid. This fluid contains fetal cells that can be analyzed to detect chromosomal abnormalities, genetic conditions, and neural tube defects.
Amniocentesis is often recommended for women who:

Have abnormal results on prenatal screening tests such as the quad screen.
Have a family history of genetic disorders.
Are carriers of certain genetic conditions.
Are advanced maternal age (typically over 35 years old), as the risk of chromosomal abnormalities increases with maternal age.

While amniocentesis carries a small risk of complications, including miscarriage and infection, it provides valuable information about the health and genetic makeup of the fetus, allowing parents to make informed decisions about their pregnancy and future care.

Anatomy Ultrasound: Around week 20 of pregnancy, a detailed ultrasound scan known as the anatomy ultrasound or fetal anomaly scan is typically performed. This comprehensive ultrasound examination evaluates the baby’s anatomy, including the brain, heart, spine, limbs, and internal organs, to ensure proper development and detect any structural abnormalities or birth defects.
During the anatomy ultrasound, the sonographer will carefully examine various fetal structures and measure specific parameters to assess growth and development. This includes:

Visualizing the baby’s brain structures and evaluating the presence of abnormalities such as neural tube defects.
Assessing the fetal heart for proper structure, rhythm, and function.
Examining the spine for signs of spina bifida or other spinal abnormalities.
Evaluating the limbs for symmetry, length, and presence of all digits.
Checking the abdominal organs, kidneys, bladder, and gastrointestinal tract for abnormalities.

The anatomy ultrasound reassures expectant parents about their baby’s health and development and allows healthcare providers to identify any potential issues that may require further evaluation or intervention.

Third Trimester

During the third trimester of pregnancy, several important tests and screenings are conducted to monitor the health and well-being of both the mother and the developing fetus. These screenings aim to detect potential complications and ensure a safe delivery. Let’s explore each of these in detail:

Glucose Screening Test: The glucose screening test, also known as the glucose challenge test (GCT), is typically performed between weeks 24 and 28 of pregnancy. This test is used to screen for gestational diabetes mellitus (GDM), a condition characterized by elevated blood sugar levels during pregnancy.

During the glucose screening test, the expectant mother drinks a sweetened beverage containing a specific amount of glucose. After waiting for a designated period (usually one hour), a blood sample is drawn to measure the blood glucose level. Elevated glucose levels may indicate gestational diabetes, which requires further diagnostic testing for confirmation.
If the initial glucose screening test results are abnormal, a follow-up test called the glucose tolerance test (GTT) may be performed. This test involves fasting overnight followed by drinking a higher concentration of glucose solution, with blood samples taken at specific intervals to measure glucose levels.
Gestational diabetes can increase the risk of complications during pregnancy and delivery, including macrosomia (large birth weight), birth trauma, and the need for cesarean delivery. Early detection and management of gestational diabetes through dietary modifications, exercise, and, in some cases, insulin therapy, can help reduce these risks and promote a healthy outcome for both mother and baby.

Group B Streptococcus (GBS) Screening: Group B Streptococcus (GBS) is a type of bacteria that can colonize the vagina and rectum of pregnant women. While GBS is usually harmless to healthy adults, it can be transmitted to the baby during childbirth and cause serious infections such as sepsis, pneumonia, and meningitis.
GBS screening is typically performed around week 36 of pregnancy. During this screening, a swab is taken from the vagina and rectum to detect the presence of GBS bacteria. If GBS is detected, the mother will be treated with antibiotics during labour to reduce the risk of transmitting the bacteria to the baby.
Screening for GBS and administering antibiotics during labour to colonized mothers has been shown to significantly reduce the risk of early-onset GBS disease in newborns, making it an essential component of prenatal care in many healthcare settings.

Non-Stress Test (NST): The non-stress test (NST) is a prenatal test used to assess the well-being of the fetus in the third trimester. It is typically performed starting around week 28 and may be repeated regularly until delivery, especially in high-risk pregnancies.
During an NST, the mother reclines in a comfortable position while a fetal heart rate monitor is placed on her abdomen to record the baby’s heart rate. The test measures the baby’s heart rate in response to its movements, with the expectation that the heart rate will increase with fetal movement, indicating a healthy, reactive fetus.
A non-reactive NST, where the baby’s heart rate does not increase adequately with movement, may indicate fetal distress or a compromised oxygen supply. Further evaluation, such as additional testing or close monitoring, may be recommended based on NST results.

Biophysical Profile (BPP): The biophysical profile (BPP) is a comprehensive prenatal test that combines fetal heart rate monitoring (NST) with an ultrasound assessment of fetal well-being. It is typically performed in the third trimester, often starting around week 32, and may be repeated as needed based on maternal or fetal risk factors.
The BPP evaluates five fetal parameters:

Fetal heart rate (measured during NST)
Fetal breathing movements
Fetal movements or body tone
Amniotic fluid volume
Reactive fetal muscle tone (gross body movements)

Each parameter is assigned a score, and the cumulative score provides valuable information about the baby’s overall well-being and the likelihood of certain adverse outcomes such as fetal distress or stillbirth.
A normal BPP score typically indicates a healthy, well-oxygenated fetus, while an abnormal score may prompt further evaluation or interventions, such as early delivery or closer fetal monitoring.

Additional Tests as Needed

High-Risk Screening: Women with certain risk factors may require additional tests or screenings, such as fetal echocardiography for cardiac abnormalities or specialized genetic testing.
Ultrasound Variants: Depending on individual circumstances, healthcare providers may recommend additional ultrasounds to monitor growth, assess placental function, or investigate suspected complications.
Cervical Length Measurement: Women at risk of preterm labour may undergo a transvaginal ultrasound to measure the cervical length and assess the risk of premature birth.

Preconception Screening

Carrier Screening: Before conception or in early pregnancy, couples may undergo carrier screening to assess their risk of passing on genetic disorders to their offspring.
Pre-existing Conditions: Women with pre-existing medical conditions such as diabetes, hypertension, or thyroid disorders may require specialized preconception counselling and screening to optimize their health before becoming pregnant.

Conclusion

By participating actively in prenatal care and adhering to recommended screenings, expectant mothers empower themselves with knowledge and agency, enabling them to make informed decisions about their pregnancy journey. These tests provide valuable insights that allow healthcare providers to tailor care plans to individual needs, address concerns promptly, and optimize outcomes for both mother and baby.

As we navigate the intricate landscape of pregnancy, let us remember the importance of regular prenatal care and the role of common tests and screenings in safeguarding maternal and fetal health. By prioritizing these screenings and engaging in open communication with healthcare providers, expectant mothers can embark on their pregnancy journey with confidence, knowing they are taking proactive steps to nurture a healthy and thriving pregnancy.

Let us embrace the journey of pregnancy with knowledge, empowerment, and a commitment to comprehensive prenatal care. By championing the importance of common tests and screenings, we pave the way for a safer, healthier, and more fulfilling pregnancy experience for all expectant mothers and their precious little ones.

Common Tests & Screenings During Pregnancy