A comprehensive guide to early pregnancy screening: part 2

Written by: Dr Panicos Shangaris
Edited by: Aoife Maguire

In the second article of a two-part series, Dr Panicos Shangaris explains how ultrasound and blood tests can identify any potential issues in pregnancy and how they can help prospective parents to prepare to welcome their baby. 




How do ultrasound scans contribute to early pregnancy screening, and what information can be obtained from these scans?


Ultrasound scans are an essential part of early pregnancy care. They use high-frequency sound waves to create images of the developing foetus and the mother's reproductive organs.


Ultrasound scans can provide the following information:


Confirmation of pregnancy and its location


An early ultrasound can confirm the presence of an intrauterine pregnancy and rule out an ectopic pregnancy (when the fertilised egg implants outside the uterus, most commonly in the fallopian tube), which can be life-threatening if not treated promptly.


Determination of gestational age


Ultrasounds can accurately determine the stage of pregnancy, based on the size of the foetus and can be used to estimate the due date.


Confirmation of fetal viability


An ultrasound can confirm if the foetus is alive by detecting a heartbeat.


Multiple pregnancies


Ultrasound can determine if there is more than one foetus.


Examination of fetal anatomy


Even in early pregnancy, some basic assessments of fetal anatomy can be made. As pregnancy progresses, more detailed anatomical scans can be performed to check for fetal physical abnormalities.


Nuchal Translucency (NT) Screening


Around 11-14 weeks, an ultrasound is used for NT screening, which measures the thickness of space at the back of the baby's neck. An increased measurement can indicate a higher risk for genetic disorders like Down syndrome and other heart or body abnormalities.


Assessment of Maternal Structures


Ultrasounds can evaluate the uterus, ovaries, and cervix, identify conditions like fibroids or ovarian cysts, and monitor the length of the cervix, which can have implications for preterm labour.


Placental Assessment


The ultrasound can check the position of the placenta, which could be important for delivery if the placenta is covering the cervix (placenta previa), or if it is showing signs of early separation from the uterine wall (placental abruption).


While ultrasound is a valuable tool, its ability to detect anomalies or conditions depends on many factors, including the equipment's quality, the pregnancy stage, the foetus's position, and the operator's skill and experience. While many abnormalities can be detected through ultrasound, not all can, so it's just one part of comprehensive prenatal care.


Are there any specific blood tests that are routinely performed during early pregnancy, and what do they help to identify or monitor?


Several blood tests are typically performed during early pregnancy to assess the health of the mother and the developing foetus. Examples include:


Full Blood Count (FBC)


This test measures several components of the blood, including red and white blood cells and platelets. It can identify conditions like anaemia, infection, and clotting issues.


Blood Type and Rh Factor


This determines the mother's blood type (A, B, AB, or O) and Rh factor (positive or negative). If the mother is Rh negative and the baby is Rh positive, it can lead to Rh incompatibility, which can cause problems in subsequent pregnancies.


Rubella Immunity (screening ended under the NHS in April 2016)


This test checks if the mother is immune to rubella (German measles), which can cause birth defects if contracted during pregnancy.


 **Hepatitis B and C (HepC not routinely done in the NHS) Tests


These tests determine if the mother has hepatitis B or C viruses, which can be passed to the baby during delivery and cause serious health problems.


Syphilis Test


Syphilis is a sexually transmitted infection that can cause serious complications during pregnancy, including infant death. However, if identified, it can be treated.


HIV Test


HIV can be transmitted from mother to child during pregnancy, childbirth, or breastfeeding. If the mother tests positive, certain treatments can significantly reduce the risk of transmitting HIV to the baby.


Varicella Immunity (not done under the NHS)


This test checks for immunity to varicella (chickenpox). If the mother is not immune, she will be advised to avoid exposure and can be vaccinated after delivery.


Thyroid Function Test (not done under the NHS)


In some cases, especially if the woman has symptoms of a thyroid disorder or a history of thyroid disease, thyroid function tests may be performed.


Glucose Screening


This test for gestational diabetes is typically done between 24-28 weeks, but it might be done earlier if the woman has risk factors for gestational diabetes, such as obesity or a family history of diabetes.


Genetic Carrier Screening


This is typically offered when there is a family history of certain genetic conditions or based on certain ethnic backgrounds. It can determine if the mother is a carrier for conditions such as cystic fibrosis, spinal muscular atrophy, or certain conditions more prevalent in specific ethnic groups, like sickle cell disease.


These blood tests are important for identifying potential issues that could affect the health of the mother or baby. If problems are identified, appropriate treatments or interventions can be implemented to manage these conditions.



What are the potential benefits and limitations of early pregnancy screening tests, and how do they help in guiding further medical interventions or decisions?


Early pregnancy screening tests provide crucial information about the health of the pregnant individual and their developing baby.  However, as with any medical test, they have both benefits and limitations.




Early Detection and Intervention


Screening tests can detect potential health issues in both the mother and baby early on, providing timely interventions, adjustments in care, or early treatment.


Informed Decision-Making


Screening results can inform parents about the likelihood of certain genetic or chromosomal conditions, which in turn helps them make informed decisions about additional testing, potential treatments, or preparation for a child with special needs.


Planning and Preparation


Test results can aid healthcare providers in providing plans for a safer delivery if certain conditions are identified, such as placenta previa or a baby with a heart defect, as well as helping parents prepare emotionally and practically for a baby with health issues or special needs.




Not Diagnostic


Screening tests provide risk assessments rather than definitive diagnoses. They can identify if a pregnancy is at higher risk for certain conditions but cannot confirm the presence of these conditions.


False Positives and Negatives


There is a risk of false positives (the test indicates a problem when there isn't one) and false negatives (the test doesn't detect a problem that is present). This can cause unnecessary worry or provide false reassurance.


Can't Detect All Problems


While these tests can screen for several conditions, they can't identify all potential health problems. Some issues may not become apparent until later in pregnancy or after birth.


Risk of Procedure-Related Complications


While most screening tests are low risk, diagnostic tests performed following a positive screening result, such as amniocentesis or chorionic villus sampling (CVS) can carry a small risk of complications, including miscarriage.


In terms of guiding medical interventions or decisions, a high-risk result on a screening test can lead to further diagnostic testing, consultations with specialists, targeted monitoring, or specific interventions during pregnancy or at delivery. These decisions are made on an individual basis, taking into account the specific condition, the overall health of the pregnant person and foetus, the desires of the parents, and the healthcare team's advice.





If you are pregnant and would like to book a consultation with Dr Shangaris, simply visit  his Top Doctors profile today.

By Dr Panicos Shangaris
Obstetrics & gynaecology

Dr Panicos Shangaris is a highly skilled consultant in obstetrics and maternal and foetal medicine in London. With over 15 years of experience, Dr Shangaris' dedicated clinical expertise specialises in all aspects of fetal medicine, pregnancy, high-risk pregnancy, prenatal diagnosis, preconception counselling, birthing control, and medicolegal cases.

In addition to his roles within the NHS and academic sectors at King's College, Dr Shangaris provides an extensive range of private maternity care services. These services include in-person consultations as well as video e-consultations. His private offerings span comprehensive antenatal care, featuring additional tests such as non-invasive prenatal testing (NIPT), as well as a range of birthing options that include both private caesarean sections and normal vaginal deliveries.

Dr Shangaris graduated from the Royal College of Surgeons in Ireland in 2005 and completed his foundation training in East Lancashire. He then pursued higher specialist training in London at renowned institutions such as University College London, the Royal Free London, Barnet, and North Middlesex Hospitals.

He obtained a Master's degree in foetal medicine and prenatal genetics at University College London (UCL) with distinction. Notably, he was awarded the prestigious Wellcome Trust SPARKS research training fellowship in 2011, which allowed him to undertake his PhD research at UCL. His research focuses on treating genetic blood disorders through foetal stem cell transplantation or gene therapy.

Dr Shangaris has received additional funding from esteemed organisations like the Academy of Medical Sciences, the National Institute for Health and Care Research, and the Fetal Medicine Foundation to further his clinical research endeavours. During his subspecialty training in maternal and fetal Medicine at St Thomas' and King's College Hospitals, he worked under the guidance of prominent experts in the field. He gained expertise in specialised clinics such as complex fetal medicine, fetal urology, gestational diabetes, hypertension in pregnancy, multiple pregnancy, fetal cardiology, genetics, and perinatal pathology.

Dr Shangaris holds the position of maternal and fetal medicine consultant at King's College Hospital NHS Foundation Trust and a Senior Clinical Lecturer at King's College London. He is also an academic co-lead for the BRC DTP PhD programme and supervises research projects for BSc, MSc, and PhD students.

With a commitment to collaborative research, Dr Shangaris actively contributes to maternal and fetal medicine clinical research, leading to numerous publications in peer-reviewed journals. He is part of the editorial team at the Reproductive Science Journal and holds the position of president of the Royal Society of Medicine, Maternity and Newborn Forum, further showcasing his leadership role in the field.

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