First screening during pregnancy: timing and norms of indicators

An essential first step in keeping an eye on your unborn child’s health and development is the screening conducted during your pregnancy. This process provides physicians with important data regarding the fetus’s growth and possible risks, enabling early intervention if needed. Many expectant parents look forward to this time with a mixture of excitement and apprehension.

For the initial screening, timing is everything. It is usually performed in the tenth or fourteenth week of pregnancy. The fetus has sufficiently matured during this time for medical professionals to measure important parameters like the mother’s blood hormone levels and the thickness of the neck fold.

Parents’ concerns may be lessened if they are aware of the typical values for these signs. In the majority of cases, the screening reassures parents that everything is going according to plan, and doctors will clearly explain the results. To ensure that the mother and unborn child have a healthy pregnancy, this initial screening is crucial.

Timing	Indicator Norms
11-14 weeks	Nuchal translucency (NT) should be between 1.6-2.5 mm
11-14 weeks	Crown-rump length (CRL) typically 45-84 mm
11-14 weeks	Heart rate (HR) usually 110-160 bpm
11-14 weeks	Free beta-hCG levels should be within standard pregnancy range
11-14 weeks	PAPP-A levels should be normal for gestational age

What is it?

Pregnant women can be so terrified of prenatal screening that they won’t even agree to have it done. Many forums for women in "interesting positions" that go into great detail about the "horrors" of screening and the experiences of mothers help to facilitate this. Actually, there are no issues with this examination. A thorough investigation called screening is done to determine whether a woman carries a higher risk of giving birth to a child who has genetic disorders.

The procedure includes laboratory testing of a pregnant woman’s venous blood in addition to ultrasound.

Translated from English, “screening” is “selection”, “screening”, “sorting”. This term is used in the economy, sociology and other areas, medicine is no exception. Pregnant women are a special category of patients who need a special approach and a more thorough medical examination. It is important to understand that screening itself does not reveal any diseases, and no diagnoses can be made for either the mother or her future child based on its results. This comprehensive examination only identifies women among the general mass of expectant mothers who have a higher risk of giving birth to a baby with severe developmental defects and genetic abnormalities than others. High risks of giving birth to a baby with pathologies are not a death sentence, and in most cases the baby is fine, but such women should be examined more thoroughly.

A woman will have these tests three times in total while she is carrying a child: once in the first trimester, once in the second, and once in the third. Pregnancy’s initial screening is thought to be the most significant and instructive.

About 20 years ago, obstetricians had a difficult time even determining the sex of the unborn child, and sometimes the pathologies affecting the baby’s development were hidden behind seven seals until the baby was born. In our nation, universal screening for expectant mothers has been implemented since 2000, and as a result, fewer babies are born with severe illnesses like Turner syndrome and Down syndrome.

Every woman who registers for pregnancy receives a referral for diagnostics, which are entirely free for the patient. The outcomes should not be used as a roadmap for quick action. A recommendation for a medically necessary pregnancy termination will be given to the mother if it turns out that the child is truly unwell.

It is entirely up to the woman to decide whether to seize this chance or to save and give birth to a "special" child; no one will pressurize her.

Goals

Prenatal testing’s primary objective is to identify pregnant women who are at risk. Naturally, nature continues to be wiser and more sophisticated than man and all of his accomplishments, so no one—not even the most skilled medical professional—can accurately predict every potential developmental abnormality that a baby may have. As a result, the list of issues is restricted to a small number of serious illnesses and conditions, the probability of which is "calculated" during the initial screening. In particular, the first screening indicates the likelihood of these pathologies.

Edwards syndrome

Among the most severe congenital malformations is this one. Chromosome 18 trisomy is the cause of its occurrence. There is a direct correlation between the age of the pregnant woman and the likelihood of this condition developing; women over 40 are more likely to give birth to a child who has this diagnosis. The disease is generally not thought to be common; the risk is approximately 0.7% for "older" moms. This does not imply that babies born to pregnant women who meet the age requirements are the only ones at risk from Edwards syndrome; even very young girls may carry an extra copy of the 18th pair of chromosomes, particularly if they have diabetes.

Infants may be born with no ear canals at all, a small mouth opening, deformed facial and cranial bones, low birth weights, and strongly modified ears. A heart defect is present in 60% of cases. Seizures, aberrant cerebellar development, and severely curved feet are present in almost all infants diagnosed with Edwards syndrome. These kids have mental retardation; the illness is called oligophrenia.

Most infants with this syndrome pass away in the first three months of life. Merely 3–5% of kids make it to the age of one year. There is no cure for the pathology; it is irreversible.

Turner syndrome

The illness is officially known as Shereshevsky-Turner syndrome. The X chromosome is affected by a chromosomal abnormality. These babies have some physical abnormalities and are born short with sexual infantilism. Premature birth is common when such a baby is born, and the pregnancy almost always develops against a backdrop of severe toxicosis and ongoing threat of termination.

In addition to the underdevelopment or absence of sex glands, the disease is accompanied by a number of skeletal system defects, including shortening of the metatarsals bones, bending of the elbow joints, and problems with the spine. Large vessels and cardiac abnormalities are the hallmarks of this syndrome, as they are of most chromosomal disorders. The type of infantilism determines how mental retardation develops; most children retain their intelligence.

Cornelia de Lange syndrome

This is a genetic illness caused by mutations in the NIPBL gene. As a result, the child has severe mental retardation, malformed cheek and cranium bones, and insufficient fingers on their hands. The syndrome is characterized by severe abnormalities affecting the kidneys, liver, cardiovascular system, and reproductive system in addition to problems with vision and hearing.

Youngsters frequently hurt themselves, have difficulty controlling their own movements, and are prone to seizures. They are insane with problems with even the most basic mental functions, depending on the kind of mental illness.

Merely 20% of these infants are free of severe psychomotor symptoms, but even they have abnormalities in the way their internal organs and bones develop.

Down syndrome

With an extra chromosome in the 21st pair, this is the most prevalent type of chromosomal pathology. Put differently, a healthy child should have exactly 46 chromosomes, whereas the baby’s karyotype has 47. These kids’ faces have changed in an odd way; they now have flatter faces, shorter necks, and flatter backs of heads. Three babies have congenital strabismus and four out of ten babies born with this syndrome have heart and vascular defects.

Genetics believes that older women have a higher chance of giving birth to a child with Down syndrome, and this belief is not without basis. The basic risk, for instance, is 1: 1500 for a young pregnant woman at age 24, and the risk rises to 1: 1000 if the expectant mother is already 28 or 29 years old. Women over 35 who are pregnant should be aware that their risk is 1: 214. The probability is at its highest (1:19) after 45.

This indicates that a dismal diagnosis affects one in every 19 children born to women over the age of 45.

Neural tube defects (anencephaly)

When a mother’s body is exposed to harmful or toxic substances at the earliest stages of her pregnancy, the defect may become "laid down." This is the time between the third and fourth weeks of pregnancy, which science is certain of.

The cerebral hemispheres’ underdevelopment or absence altogether are signs of defects; occasionally, the skull’s bones are also absent. The infant thus has no head at all. This flaw is entirely fatal. While some babies make it to birth alive, the majority of babies pass away in the womb and are not meant to live long, happy lives.

Less frequently, the infant can "hold out" for a few days before dying in the first few hours after birth.

Smith-Lemli-Opitz syndrome

A disorder caused by a congenital lack of 7-dehydrocholesterol reductase, a unique enzyme that produces cholesterol. Since cholesterol is so essential to a living cell, a deficiency in the substance causes problems for all organs and systems at the cellular level. The type of deficiency determines how severe the disease is in a child. If there is a small deviation, the child will experience mild mental problems; if there is a significant deficiency, the illness will cause severe physical and mental abnormalities.

These babies have a smaller brain, many have autism, malformed bones and tendons, internal organ defects, and sometimes vision and hearing problems. A malfunction in the DHCR7 gene results in a shortage of a crucial enzyme.

Although the condition is uncommon in and of itself, the syndrome was screened for because every thirty adults carry a mutated copy of the DHCR7 gene. The only remaining question is whether the child’s father or mother will carry this gene or not.

Non-molar triploidy

A severe genetic disorder that arises "by the will of Mother Nature" and is linked to a variation in the number of chromosomes in any pair. The child is laid in 46 or 69 pairs, not 23, which is not the fault of either parent. Since a fetus with such a karyotype cannot survive, most of the time it dies in the mother’s womb. Nevertheless, there are some exceptions, such as when the baby is born and passes away within a few days or hours after birth. Even in cases where both parents are perfectly healthy and do not carry any genetic diseases, pathology may still develop.

This couple may have great success in their next attempt to conceive, and there is very little chance that non-molar triploidy will recur.

Patau syndrome

This condition, also known as trisomy 13 chromosome, is brought on by an extra chromosome in the 13th pair. Physicians observe a distinct correlation between the mother’s age and the occurrence of chromosomal abnormalities. The older the expectant mother gets, the greater the risks.

The syndrome occurs with gross developmental defects – the child"s facial bones are distorted, the brain is very small in size. The organs of vision and hearing may be underdeveloped or completely undeveloped. The so-called cyclopia is often encountered, when the child has only one eye located in the center of the forehead. There may be multiple clefts of the facial bones. The syndrome is accompanied by malformations of the internal organs, as well as uncorrectable disorders of the central nervous system. Many children die in the first months after birth, only a few manage to live to 5-7 years, and they are deep idiots, learning or self-care, as well as interest in anything in such a baby are completely excluded.

There has been a notable decrease in the number of babies born with these conditions since screening became required. As a result, while one in 700 babies were born with Down syndrome prior to 2000, only one in 1200 babies now have the condition after doctors were able to identify the risks. Even in these cases, the parents made the decision to have the child because, in recent years, society’s perception of "sunny" babies has shifted, and some mothers purposefully choose to carry their pregnancy even though they know they should have a special baby.

While other diagnostic techniques—discussed below—can determine the truth, prenatal diagnostics only reveals some indications of potential defects, not pathologies.

Risk group

Any woman can acquire any of the pathologies listed above, but certain women are considered to be at a higher risk than others. Among them are expectant mothers who are more likely than others to have a fetus with genetic issues.

• late-birthing (if the pregnant woman is over 35 years old);
• pregnant women who have previously had miscarriages due to chromosomal abnormalities in fetal development, as well as women who have given birth to children with hereditary diseases;
• girls and women with a history of more than two miscarriages that occurred one after the other;

• pregnant women who, due to ignorance or other reasons, continued to take medications at the beginning of pregnancy that are prohibited during pregnancy;
• pregnant women from a close blood relative;
• pregnant from donor sperm;

• women who do not have information about the health of the child"s father and have no contact with him;
• women working in hazardous conditions, especially if their work is associated with radiation exposure, as well as women whose men work in such conditions and are exposed to radiation;
• women who have relatives with genetic diseases in their family history, as well as ladies whose spouses have such relatives.

The likelihood of anomalies is reduced but not totally eliminated if a young girl conceives a desired child from a fully healthy man. It is crucial that you submit to this kind of testing for this reason.

Even though screening is required for all individuals, no procedure can be carried out without the pregnant woman’s consent; if this is the case, no one will force the expectant mother to be examined, even if she is in the risk group.

Timing

Between the eleventh and thirteenth week of pregnancy, there are specific times during which the first prenatal screening is conducted. It should be noted that a woman may be referred for testing and ultrasound at both the eleventh (ten complete obstetric weeks) and fourteenth (at thirteen complete weeks) weeks of pregnancy. Since the information content of some markers and indicators is high only during the designated period, the first trimester screening exam is not performed later.

Contrary to popular belief, obstetric weeks do not correspond to the number of weeks since conception. This is the amount of time that has elapsed since the last menstrual cycle began. Obstetric weeks, then, are the two weeks after conception plus one. This indicates that the fetus will be between 9 and 11 weeks gestational age at the time of the examination.

The doctor that the expectant mother is registered with provides the referral. If a woman registers after 13 weeks, the first screening is not performed for her, and she is solely responsible for any potential undiagnosed pathologies in the unborn child.

An essential medical examination known as the first screening occurs during pregnancy and typically occurs between weeks 11 and 14. It assists in evaluating the infant’s growth and early identification of any possible health problems. To check for genetic abnormalities and make sure the mother and the unborn child are healthy, this screening consists of blood tests and an ultrasound. During this exciting stage of pregnancy, parents can feel more prepared and informed if they know what to expect and what the normal range of results is.

Preparation

It is difficult for doctors to examine a small baby because the initial screening is done in a short amount of time. A number of factors, including the mother’s body temperature and unhealthy behaviors like alcohol or tobacco use, can influence the examination’s outcomes. A pregnant woman’s final result may also be impacted by sleep deprivation, anxiety, or toxicosis, particularly when it comes to the blood test’s parameters.

An evaluation of overall health is part of the preparation for the initial assessment. A woman has to report to her doctor her symptoms, including fatigue, an infectious disease, or a cold, as well as whether or not she is getting enough sleep.

A woman should go to the ultrasound diagnostic room a few hours before to ensure that her bladder and bowel movements are clear. This will help the ultrasound results be more accurate and allow the doctor to examine the baby more thoroughly. You should take a dose of "Simethicone" or "Espumisan" to get rid of intestinal gases. The diagnosis may become more difficult if there is a lot of gas because the bloated intestines may compress the pelvic organs.

There’s no need to fill the bladder beforehand because at this point the ultrasound is usually done transvaginally.

The blood test is the one for which you should be most prepared because biochemical studies can be impacted by other factors. The woman is advised to follow a mild diet a few days prior to the screening, which completely avoids fried and fatty foods, spices, smoked foods, too-salted foods, and pickled foods. You should also avoid eating a lot of raw vegetables, cabbage in any form, legumes, fatty dairy products, baked goods, and sweets to help prevent gas formation in the intestines.

Eating is prohibited prior to the procedure. No later than six hours prior to the tests, should the last meal be consumed.

Procedure

Out of the three prenatal screenings, the first trimester screening is the most thorough and informative. It needs to be done in a specific order. It is crucial that ultrasound diagnostics and laboratory testing be done on the same day, albeit slightly apart in time.

The woman arrives for the consultation at the scheduled time, which is typically in the morning since she should come empty-handed. She first visits her obstetrician-gynecologist’soffice. There, she will complete a unique diagnostic form with the information required to make genetic predictions. The prediction will be more accurate the more facts that are entered into the form.

The woman’s and her partner’s ages, the pregnant woman’s weight, her height, and her obstetric history are all vital diagnostic details. Pregnancy history prior to the current pregnancy and its outcome must be disclosed. If the cause of the miscarriages is known with certainty and supported by the results of the biopsy, you should mention it.

A woman’s history of congenital defects and chromosomal syndromes in her offspring is also reported, as is the existence of family members with inherited illnesses.

It should be mentioned if a pregnant woman smokes, uses drugs, or drinks alcohol because these unhealthy behaviors will undoubtedly alter the blood’s composition. The expectant mother’s chronic illnesses are all listed on the diagnostic form.

Following this, the expectant mother visits the procedure room or gets an ultrasound. There are conflicting recommendations about what should happen next. In the consultations with Russian women, the ultrasound diagnosis is typically made first, and the pregnant patient’s blood is then drawn right away for a biochemical analysis. If the woman is thin and the view through the anterior abdominal wall is unobstructed, ultrasound can be done both transvaginally and transabdominally using a sensor on top of the abdomen.

This method is the best for the first trimester in general and for women who are at risk of miscarriage in particular, as it allows a detailed examination of the cervical canal condition in addition to the child. The vaginal sensor is used to view through the vaginal wall from the inside.

Via a vein is how blood is traditionally drawn. Every tool and test tube is sterile and disposable. The woman receives the results of the ultrasound test right away, but she must wait a few days or even weeks for the results of the laboratory blood tests.

Since the ultrasound is not taken into consideration independently from the laboratory data, the woman receives a general conclusion about passing the screening along with the calculated risks of fetal pathologies after the blood tests are ready.

What can be seen on the ultrasound?

The woman will get to see her baby during the first screening ultrasound. This is often the first time they have ever met the baby. Even though the mother cannot yet feel it, a child who has transitioned from an embryo to a fetus will be able to please her with his loud and regular heartbeat and demonstrate to her how well he has learned to move. The number of fetuses, their viability, and their developmental characteristics can all be found out via an ultrasound at the end of the first trimester.

The fetus’s size aids in pinpointing the precise moment and estimating the expected birth date.

At this point, a good high-resolution ultrasound scanner displays the fetus’s head, facial profile, arms, legs, fingers, and eye sockets. In addition to checking the amniotic fluid, the doctor will be able to examine the placenta, umbilical cord, uterus, and tubes. Determining whether the baby is likely to have a congenital chromosomal disease depends on a number of so-called markers of genetic pathologies.

Theoretically, the doctor can determine the child’s sex with a good view and a good device, but he cannot guarantee anything as the sexual differences between boys and girls are not as noticeable during this stage of pregnancy.

The woman will have to pay for this service in accordance with the tariffs for the provision of paid services of the specific medical organization where she undergoes diagnostics since determining the child’s sex is not one of the questions that doctors find interesting during screening. The only exceptions are situations in which the baby’s gender determines their genetic well-being. Hemophilia, for instance, is unique to boys.

Gender identity is useful in diagnosis because a woman who carries this disease has a high chance of passing it on to her son.

An important first step in keeping an eye on the health of both the mother and the unborn child is the prenatal screening. It guarantees that everything is moving forward as it should and assists in spotting any early warning indications of possible problems.

During this crucial stage of pregnancy, parents can feel more prepared and at ease if they know what the various indicators mean and when they should be acting.

In the event that any concerns surface, the screening enables medical professionals to intervene as soon as necessary, giving mom and child greater peace of mind and better results.

Video on the topic

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