Like any other study, prenatal examination at different stages of pregnancy has its goals. It is important to know that the specialist who performs it should be aware of these goals and explain them to his patients before the study. This article was provoked by false, incomplete and incompetent opinions that have been written and spoken in many places on the Internet space in Bulgaria. The reasons for this, I think, are ignorance of matter, financial interests, or is provoked by a distorted personal sense of justice. Unfortunately, there are many people who, without having the necessary knowledge, express a ‘convincing’ opinion.

Performing an ultrasound examination during pregnancy may be both routine and family-related, past or current maternal illness, genetic abnormality carriership, open fetal deviation, and so on.

For routine examinations, we accept examinations in 11-14 WOG, 18-22 WOG and 32 and/or 36 WOG. I believe that the reason for each of these examinations has been specified in the articles for the appropriate period of pregnancy, but I will still allow myself to describe the goals once more. All of these examinations are routine and should be performed on any pregnant woman to track the normal development of pregnancy, fetus, placenta, amniotic fluid and blood flow (Doppler study).

I start with the examination in first trimester or the one between 11-14 WOG. During this period of pregnancy, all organs and systems of the fetus are formed, from here onwards they follow their maturation. Until this period of pregnancy the risk of miscarriage was 15%, after 12 WOG is now only 2-3%. This should be a moment of relief for you, future mothers. Of course, you may still have morning nausea and vomiting, but if you do not have more than four to five times a day, not connected with eating, take enough liquids and manage to eat, though less, you need to be calm. Soon and morning nausea and vomiting will pass away. For those who have vaginal bleeding and morning nausea, do not worry, the fact that these are  two separate symptoms does not increase the risk of abortion, but it just reduces it. It is unclear why, in bleeding and nausea, the risk of abortion is lower, but is described in most textbooks and manuals. After the brief introduction/deviation, I begin with the reasons for performing a 11-14 WOG ultrasound examination. Before the examination, each doctor ‘takes’ a detailed history (questioning) of the patient. If you have not had another examination to date, which I doubt, but in the UK this is mostly the first examination, now is the time to determine the place and the number of fetuses. I.e. whether the pregnancy is singleton, bigeminal, triple, etc. In humans, the most common spontaneous pregnancy is singleton, rarely there is bigeminal, and extremely rarely multifetal pregnancy. With in vitro fertilization and embryo transfer of more than one embryo, the number of multifetal pregnancies increases. When multiple pregnancies occur, one should determine whether they share one placenta or have separate placentas. In the presence of multiple pregnancies with one placenta, the risk of complications of pregnancy is much greater and requires frequent follow-up. The next step is the presence of cardiac activity on each fetus. Every parent is excited to hear the throb of the heart of his child.

After determining the number of fetuses and heart activity, the placental location, a subjective assessment of the amniotic fluid should be determined. During this period of pregnancy, it is found to be the most accurate time to date the pregnancy and to tell you the term. Yes, that’s right, we will now measure the fetus and according to its size, we will determine how far the patient is gone in pregnancy. For this purpose, the fetus should be within a range between 45mm and 84mm. Once we give you the new term from here until the end of pregnancy, it will be our guide and will not change for any reason! Defining the term on the last menstrual period is not so accurate method, because even if you have a very regular period, few women know exactly when ovulation has occurred. Even if you are aware of the date of ovulation and the date of the sexual intercourse, it is also important to specify that the sperm life is between 24-48-72h, and the ovum 24-48h., i.e. the actual fertilization can be done with a difference of 2 to 3 days. And this is important in tracking pregnancy and fetal growth. The most accurate method for dating pregnancy is in in vitro fertilization and fresh transfer. Then we know the exact moment of fertilization and the date of the term has to be determined by the clinic in which the in vitro procedure was performed. Therefore, in patients with such pregnancy, we do not change the term and do not date.

Among the main objectives of the examination in the first trimester between 11-14 WOG is screening for the most common chromosomal abnormalities – Down, Patau and Edwards syndrome. Combined screening test is performed and the risk for each of these anomalies is calculated by the age of the woman, biochemical parameters from the blood test, and ultrasound markers and parameters.

And here comes the question why we need to examine if your child can have a Down syndrome!? The analysis, especially combined screening test, and cff DNA, are non-invasive procedures related only to taking venous blood from the pregnant woman. These methods do not pose a risk either to you or your baby. With these two methods, screening is also done for Patau and Edwards syndromes. Detecting some of these syndromes would be extremely helpful for both you as a prospective parent and for us, the medics. It is important for parents because they will be able to make the right decision for them - whether to continue pregnancy or discontinue it. I.e. the presence of any of these or other abnormalities in no way obliges you to commit an abortion! This decision is ONLY YOURS! We will support you in your choices with understanding, with more information and the follow-up medical activities dictated by you. If you do not want to have a child with some of these syndromes, the end of the first trimester is the most appropriate and poses the least hazards for you and your childbearing ability. If you decide to continue your pregnancy, you will become more aware of this condition, look for more information, and you will be far more prepared to take care of your child and what you will experience after birth. For us, doctors, it is important to be able to track pregnancy more closely, to look for anomalies in detail, to plan birth, and not least to give you advice on next pregnancies, to direct you to genetic counseling if necessary, to determine the risk of recurrence of this syndrome in the next pregnancy.

Another important objective of the examination in 11-14 wog is the trace of anatomy of the fetus in the early stages of pregnancy and detection of abnormalities. Yes, even in this early period, it is possible to detect multiple abnormalities.

Fetal morphology takes place between 19th and 22nd WOG. The aim of fetal morphology is to trace the normal anatomical and physiological development of the fetus for this period, to make biometric measurements, respectively to detect pathological changes, if any, to conclude and determine the follow-up. It is a highly specialized study done with a high-resolution echograph.

If we detect deviations during this period of pregnancy, we should ask ourselves the following questions: What is this anomaly? Is it related to other deviations? What are the consequences of this/these anomalies? Is this condition compatible with life? What is the severity of the anomaly? What can be the reasons? How can these reasons be detected? What can we do? What alternatives do we have? Once we answer all these questions together, we come to a decision on the follow-up and alternatives. In some severe anomalies, the possibility of interruption of pregnancy may be considered.

Fetal morphology is done until the 22nd WOG as long as there are serious anomalies within this time, there is a time up to 24 WOG until an abortion can be made on medical evidence. After this period, a medical abortion can only be performed in conditions that endanger the mother’s life.

Examination after 28 week of gestation or monitoring the growth of the fetus. The aim is to trace the dynamics of how the fetus grows, the sequence of the growth of the individual indicators, the relationship between them and the sequence as a whole. We look at the placenta again for position, structure and maturity. We measure the presence of amniotic fluid, maternal blood flow to the placenta, placenta to the fetus and blood flow of the fetus. We observe breathing movements, body movements and the limbs of your baby. All this shows us the viability of the fetus, the discovery of early signs of suffering of the fetus of different nature and the possibility of drawing up a follow-up plan.

Of course, within this period, we are doing biometric measurements of the fetus to track its growth. Deviations from the norm may be in one direction or another and signal a different pathology. It is important to trace not only whether it is in the norm but also the systemacity of growth, i.e. whether it follows one growth line or there are deviations from that line. A complete idea of growth needs to be built up to draw conclusions. If there are any deviations, the reasons are sought with further studies and more frequent tracing of the fetus with an echograph.

Screening in the first trimester, screening for Down Syndrome, combined screening test or early biochemical screening are all synonyms but it is best to talk about screening in the first trimester. Now I’m going to explain why. We need to understand what this screening is and what its objectives are.

Combined screening test is performed to detect trisomy 21 (Down Syndrome), trisomy 13 (Patau Syndrome), and trisomy 18 (Edwards Syndrome).

Since the beginning of 2017 we already have screening and prevention of preeclampsia (complication after mid pregnancy manifested by multi-organ involvement, increased blood pressure, protein in the urine, edema, fetal growth retardation, etc.). Since this condition affects between 4-5% of all pregnant women, and according to data from three centers in Bulgaria even 7-8%, it is definitely a more significant problem from several points of view. First of all, its higher rate makes it a socially significant problem, and in terms of its possible prevention in up to 89% in the population at risk, it is extremely important to reduce the occurrence of preeclampsia.

Screening (from English screening: sifting, selection) is a systematic, research method in the field of medicine, the purpose of which is to make a preliminary selection through a general classification in a pre-selected area of study (samples or individuals). Pre-selection or stratification of the sample serves to gather objects that carry certain attributes and later undergo a special study. from Wikipedia, the free encyclopedia.

In the UK (I can comment to some extent on the healthcare system in this European country in particular because of my experience there as a duty doctor in private hospitals, an obstetrician in state hospitals and specializing in fetal medicine there, I have not worked and studied in other countries and I would not allow myself to comment), the majority of the first ultrasound examinations of pregnant women take place between 11 and 14 weeks of pregnancy. To clarify, pregnancy lasts 280 days, 10 lunar months (by 28 days) or 40 weeks of pregnancy (WOGP) from the first day of the last menstrual period. In Western literature, pregnancy is counted in weeks, so I will describe it divided in weeks. It is precisely because of the fact that the first examination is in this period and it has several purposes.

Before we start with the ultrasound, we need to collect data about the pregnancy and the woman, the so-called history. We ask about your age, LMP (first day of the last menstrual period), the way of conception - spontaneous/natural or in vitro, problems during pregnancy, alcohol, cigarettes and drugs consumption, past and current diseases, previous surgeries, previous pregnancies, a problem during previous pregnancies, family illness, etc. All of this gives us information about your health and possible risks for your current pregnancy, which enables us to develop a follow-up plan.

I’m sure most of you are aware that a blood sample is taken. We assess the level of free bHCG and PAPP-A. The relationship between the pregnancy hormone (free bHCG) and the pregnancy protein (PAPP-A) is a marker for chromosomal diseases that are important for calculating the risk for the three most common trisomes - Down Syndrome (trisomy 21), Patau Syndrome (trisomy 13) and Edwards Syndome (trisomy 18). They also have significance for the detection of triploids, predictive markers for preeclampsia and IUGR (fetal retardation).

Another blood test we do is for PlGF (placental growth factor) to screen for preeclampsia. High blood pressure during pregnancy is a common and serious complication. Over the course of at least 2-3 decades, numerous studies have been conducted in this field. From 2014 to 2016 under the leadership of Professor Kypros Nicolaides, several studies were carried out in this direction, two of which ASPRE and SPREE trails, in which I can proudly say that I participated. These two studies confirmed the sensitivity of the test method and the method for preeclampsia prevention. I believe this screening should be offered to every pregnant woman because of the great results I have witnessed in my practice.

The first goal of screening in the first trimester is to establish an intrauterine pregnancy with a viable embryo or fetus after 12 WOP, through hearbeat ultrasound, fetal movements, Doppler ultrasound confirming cardiac activity and the establishment of singleton or multiple pregnancy. If there are two or more fetuses, one should determine whether they have a common placenta or individual placenta, as well as general or separate amniotic sacs. The next step is to measure the size of the fetus, i.e CRL (crown-rump length), which determines the exact duration of pregnancy and determines EDD (estimated date of delivery) if the pregnancy has occurred spontaneously. We believe that during this period of pregnancy, all fetuses are of the same length and by accurately measuring them, according to very strict criteria, we may determine the due date with great precision. Pregnancies that occurred after in vitro fertilization with the transfer of a fresh embryo, the due date is determined by the in vitro protocol.

The method of determining the due date according to Naegele’s formula (LMP - 3 months, + 7 days) is old and gives significant deviations. With a fresh transfer, the day and the fertilization time is clear, so this is the most accurate way to know the exact due date. Transfering frozen embryo is again determined by the in vitro protocol, but the CRL method can also be used. The importance of determining the exact term is not just a whim on the part of doctors but is essential to track the growth of the fetus. Deviations from normal height parameters may indicate inaccuracies in determining the due date, but may be an indicator of many diseases.

Combined screening test aims to detect the most common chromosomal illnesses by calculating the risk based on your age, some factors from your anamnesis, blood tests, and ultrasound markers. Ultrasonic markers include nuchal translucency (fluid behind the fetus’ neck), nasal bone, ductus venosus (blood vessel in the liver of the fetus), tricuspid blood flow (right heart blood flow) and heart rate. All of these markers have strict criteria for their identification and any deviation from these criteria leads to false results.

The next step is to examine the anatomy of the fetus. Between 11 and 14 WOP the embryo has a length of 45 to 84 mm and of course this makes this part of the testings not very easy and has its limitations, but an experienced specialist can detect or reject a lot of pathology. You may not believe it, but a high-resolution ultrasound and an examination by a fetal medicine specialist can reject at this stage 83% of the major heart abnormalities. I would like to add that these are complex (large) cardiac anomalies. Keep in mind that up to 30% of all cardiac abnormalities are detected by fetal medicine specialists in the United Kingdom, and up to 50% of them in utero in the large specialist cardiac centers.

Organogenesis (organ formation) is largely completed at this stage, but there are still structures that are still being formed, such as the brain, and we track their development at this stage. Even with such small fetal dimensions, we can visualize the head, brain, eyes, hard palate, heart, spine, stomach, kidney, bladder, limbs, placenta and amniotic fluid, as well as discover or reject anomalies in all these structures.

After the examination, you should have the results. It is important to understand that a combined screening test is not a diagnostic method but a screening method. I.e. we will give you as a result about the possibility your baby be born with Down, Patau, or Edwards syndromes. Combined screening test, which is performed by a certified fetal medicine specialist, (you can check if your doctor is certified by FMF London on the following website https://fetalmedicine.org/ ) can detect between 90-95% of the fetuses affected by Down Syndrome. For several years, there has been a new screening method for detecting Down, Patau, Edwards syndromes and some DNA anomalies by isolating fetus DNA from the mother’s blood. The method is 99.2% reliable, safe and easy to implement. Of course, I personally would advise you to consult with a fetal medicine specialist before doing this test and after you get the results for several reasons. Keep in mind that this blood test detects isolated counts of syndromes, and there are many other conditions which cannot be detected. Interpreting the result of the free cell DNA test should be based on combined screening test by a specialist who has the knowledge about it.

Biochemical screening is based on blood sampling and the study of hormone (free bHCG) and protein (PAPP-A) only produced during pregnancy. There is no scientific data on this method for its accuracy. When biochemical screening is combined with other factors, it attains certain meaning. It has been found that using only maternal age (MB) can detect up to 30% of the fetuses with Down syndrome; combining MB + biochemical serum (free bHCG, estradiol, Inhibin A, alpha-feto protein) between 15 and 18 weeks of pregnancy (WOP) increases the detection to 50-70%; MB + nuchal translucency (the fluid behind the fetus’ neck in 11-14 WOP) increases to 70-80%; MB + nuchal translucency** + biochemical serum (free bHCG and PAPP-A) in 11-14 WOP increases detection to 85-90%; MB + nuchal translucency** + nasal bone** of the fetus in 11-14 WOP increases detection to 90% and MB + nuchal translucency** + nasal bone** + biochemical serum (free bHCG and PAPP-A) of the fetus in 11-14 WOP increases the detection to 95%. The latter method is called combined screening test. As with any screening, here I have false positive results at 5%. This means that of all women who are being screened, 5% of them will get positive results without their fetuses being affected.

* The text is borrowed from ‘The 11–13+6 weeks scan’ Prof. Kypros Nicolaides

** ultrasonic markers for detection of chromosomal abnormalities – nuchal translucency, nasal bone, tricuspid regurgitation, blood flow in ductus venosus, heart rate

If, for any reason, a combined screening test between the 11th and 14th WOP is missed, a later biochemical screening may be performed. Between the 15th and the 18th week of pregnancy, blood sampling for biochemical serum testing (free bHCG, estradiol, Inhibin A, alpha-feto protein) as well as an ultrasound scan to establish the pregnancy due date can be performed. The credibility of the method is up to 50-70% with a high percentage of false positive results.

Methods for detecting 100% chromosomal and DNA abnormalities are chorionic villus sampling and amniocentesis. These are invasive procedures that involve the risk of miscarriage or premature birth, depending on how long they are performed. Once again, the discussion of the risk of abortion as a result of these examinations is coming back to the agenda. For the moment, we can say that the risk is 1% or 1 in 100 manipulations. A risk of 0.2% or 1 in 500 is mentioned, but many factors such as specialist experience, the risk of abnormalities in the fetus, etc. should not be forgotten.

Yet you are pregnant, enjoy your pregnancy! Take care of yourself and pay attention to you and your loved ones. I’ll open a bracket again and warn you about weight gain during pregnancy - according to the latest research, women who put on too much weight raise the risk of preeclampsia. For this, eat mindfully, move and remember that pregnancy is a physiological process, not a disease.

Author: Dr. Boris Stoilov

Preeclampsia is one of the most common complications of pregnancy, affecting 5-10% of all pregnant women. It represents increased blood pressure above, 140/90 mmHg, and protein in the urine after mid-pregnancy (after 20 weeks of gestation). Preeclampsia is the leading cause of hospital admissions for pregnant women and the number 1 cause of medically induced preterm delivery. In addition, I want to say that this condition is among the leading for maternal and neonatal mortality and morbidity. As it turns out, this symptom is one of the most serious complications of pregnancy.

In the last decades there have been various studies related to the causes of its development, its treatment and prevention. For now, the main treatment is the delivery of the baby and the placenta, which is why it is also the leading reason for an earlier birth. In its turn, the earlier birth of an immature fetus can lead to a number of complications for the newborn – difficulty breathing or the inability to breathe independently, infections of various systems, problems in the digestive system, cerebral palsy, and even death.

The objective of some researchers in the last ten years has been the earlier detection of preeclampsia, even prediction of the women who will develop it, and preventing it. Professor Nicolaides and his team created a screening test to identify at-risk patients. This screening detects up to 90% of women who will develop the unwanted complication. More importantly, the famous professor also created a method to prevent this condition in up to 89% of the women who will develop it.

I am proud of the fact that I also participated in these large-scale studies that made a significant breakthrough in prenatal care and maternal health. Since this is a symptom with a particularly large effect on pregnancy, it affects both the pregnant woman and the fetus, the main mission of the Maternal-Fetal Medicine Center is the prevention of as many complications as possible. Our equipment is state-of-the-art and our specialists are trained and committed to the latest trends in medicine based on serious scientific studies.

To all our patients we offer screening and prevention of Preeclampsia. This test is performed in 11-14 weeks of gestation, along with screening for Down syndrome and early fetal morphology. It includes a detailed collection of data for the medical record, taking and analyzing a blood sample (within the day), measuring blood pressure several times and detailed ultrasound examination. Our patients receive their results within 2 hours of taking the blood sample, which few centers in the country can do!

Author: Dr. Boris Stoilov