Blood test at 12 weeks
Screening for Down's syndrome, Edwards' syndrome and Patau's syndrome
You will be offered a screening test for Down's syndrome, Edwards' syndrome and Patau's syndrome between 10 and 14 weeks of pregnancy. This is to assess your chances of having a baby with one of these conditions.
Down's syndrome is also called trisomy 21 or T21. Edwards' syndrome is also called trisomy 18 or T18, and Patau's syndrome is also called trisomy 13 or T13.
If a screening test shows that you have a higher chance of having a baby with Down's syndrome, Edwards' syndrome or Patau's syndrome, you'll be offered further tests to find out for certain if your baby has the condition.
What are Down's syndrome, Edwards' syndrome and Patau's syndrome?
Down's syndrome
Down's syndrome causes some level of learning disability.
People with Down's syndrome may be more likely to have other health conditions, such as heart conditions, and problems with the digestive system, hearing and vision. Sometimes these can be serious, but many can be treated.
Read more about Down's syndrome
Edwards' syndrome and Patau's syndrome
Sadly, most babies with Edwards' syndrome or Patau's syndrome will die before or shortly after birth. Some babies may survive to adulthood, but this is rare.
All babies born with Edwards' syndrome or Patau's syndrome will have a wide range of problems, which can be very serious. These may include major complications affecting their brain.
Read more about Edwards' syndrome and Patau's syndrome.
What does screening for Down's syndrome, Edwards' syndrome and Patau's syndrome involve?
Combined test
A screening test for Down's syndrome, Edwards' syndrome and Patau's syndrome is available between weeks 10 and 14 of pregnancy.
It's called the combined test because it combines an ultrasound scan with a blood test. The blood test can be carried out at the same time as the 12-week scan.
If you choose to have the test, you will have a blood sample taken. At the scan, the fluid at the back of the baby's neck is measured to determine the "nuchal translucency". Your age and the information from these 2 tests are used to work out the chance of the baby having Down's syndrome, Edwards' syndrome or Patau's syndrome.
Obtaining a nuchal translucency measurement depends on the position of the baby and is not always possible. If this is the case, you will be offered a different blood screening test, called the quadruple test, when you're 14 to 20 weeks pregnant.
Quadruple blood screening test
If it was not possible to obtain a nuchal translucency measurement, or you're more than 14 weeks into your pregnancy, you'll be offered a test called the quadruple blood screening test between 14 and 20 weeks of pregnancy.
This only screens for Down's syndrome and is not as accurate as the combined test.
20-week screening scan
For Edwards' syndrome and Patau's syndrome, if you are too far into your pregnancy to have the combined test, you'll be offered a 20-week screening scan. This looks for physical conditions, including Edwards' syndrome and Patau's syndrome.
Can this screening test harm me or my baby?
The screening test cannot harm you or the baby, but it's important to consider carefully whether to have this test.
It cannot tell you for certain whether the baby does or does not have Down's syndrome, Edward's syndrome or Patau's syndrome, but it can provide information that may lead to further important decisions. For example, you may be offered diagnostic tests that can tell you for certain whether the baby has these conditions, but these tests have a risk of miscarriage.
Do I need to have screening for Down's syndrome, Edwards' syndrome and Patau's syndrome?
You do not need to have this screening test – it's your choice. Some people want to find out the chance of their baby having these conditions while others do not.
You can choose to have screening for:
- all 3 conditions
- Down's syndrome only
- Edwards' syndrome and Patau's syndrome only
- none of the conditions
What if I decide not to have this test?
If you choose not to have the screening test for Down's syndrome, Edwards' syndrome or Patau's syndrome, you can still choose to have other tests, such as a 12-week scan.
If you choose not to have the screening test for these conditions, it's important to understand that if you have a scan at any point during your pregnancy, it could pick up physical conditions.
The person scanning you will always tell you if any conditions are found.
Getting your results
The screening test will not tell you whether your baby does or does not have Down's, Edwards' or Patau's syndromes – it will tell you if you have a higher or lower chance of having a baby with one of these conditions.
If you have screening for all 3 conditions, you will receive 2 results: 1 for your chance of having a baby with Down's syndrome, and 1 for your joint chance of having a baby with Edwards' syndrome or Patau's syndrome.
If your screening test returns a lower-chance result, you should be told within 2 weeks. If it shows a higher chance, you should be told within 3 working days of the result being available.
This may take a little longer if your test is sent to another hospital. It may be worth asking the midwife what happens in your area and when you can expect to get your results.
You will be offered an appointment to discuss the test results and the options you have.
The charity Antenatal Results and Choices (ARC) offers lots of information about screening results and your options if you get a higher-chance result.
Possible results
Lower-chance result
If the screening test shows that the chance of having a baby with Down's syndrome, Edwards' syndrome and Patau's syndrome is lower than 1 in 150, this is a lower-chance result. More than 95 out of 100 screening test results will be lower chance.
A lower-chance result does not mean there's no chance at all of the baby having Down's syndrome, Edwards' syndrome or Patau's syndrome.
Higher-chance result
If the screening test shows that the chance of the baby having Down's syndrome, Edwards' syndrome or Patau's syndrome is higher than 1 in 150 – that is, anywhere between 1 in 2 and 1 in 150 – this is called a higher-chance result.
Fewer than 1 in 20 results will be higher chance. This means that out of 100 pregnancies screened for Down's syndrome, Edwards' syndrome and Patau's syndrome, fewer than 5 will have a higher-chance result.
A higher-chance result does not mean the baby definitely has Down's syndrome, Edwards' syndrome or Patau's syndrome.
Will I need further tests?
If you have a lower-chance result, you will not be offered a further test.
If you have a higher-chance result, you can decide to:
- not have any further testing
- have a second screening test called non-invasive prenatal testing (NIPT) – this is a blood test, which can give you a more accurate screening result and help you to decide whether to have a diagnostic test or not
- have a diagnostic test, such as amniocentesis or chorionic villus sampling (CVS) straight away – this will tell you for certain whether or not your baby has Down's syndrome, Edwards' syndrome or Patau's syndrome, but in rare cases can cause a miscarriage
You can decide to have NIPT for:
- all 3 conditions
- Down's syndrome only
- Edwards' syndrome and Patau's syndrome only
You can also decide to have a diagnostic test after NIPT.
NIPT is completely safe and will not harm your baby.
Discuss with your healthcare professional which tests are right for you.
Whatever results you get from any of the screening or diagnostic tests, you will get care and support to help you to decide what to do next.
If you find out your unborn baby has Down's syndrome, Edwards' syndrome or Patau's syndrome
If you find out your baby has Down's syndrome, Edwards' syndrome or Patau's syndrome a specialist doctor (obstetrician) or midwife will talk to you about your options .
You can read more about what happens if antenatal screening tests find something.
You may decide to continue with the pregnancy and prepare for your child with the condition.
Or you may decide that you do not want to continue with the pregnancy and have a termination.
If you are faced with this choice, you will get support from health professionals to help you make your decision.
For more information see GOV.UK: Screening tests for you and your baby
The charity Antenatal Results and Choices (ARC) runs a helpline from Monday to Friday, 10am to 5.30pm on 020 7713 7486.
The Down's Syndrome Association also has useful information on screening.
The charity SOFT UK offers information and support through diagnosis, bereavement, pregnancy decisions and caring for all UK families affected by Edwards' syndrome (T18) or Patau's syndrome (T13).
First trimester screening - Mayo Clinic
Overview
Nuchal translucency measurement
Nuchal translucency measurement
First trimester screening includes an ultrasound exam to measure the size of the clear space in the tissue at the back of a baby's neck (nuchal translucency).
In Down syndrome, the nuchal translucency measurement is abnormally large — as shown on the left in the ultrasound image of an 11-week fetus. For comparison, the ultrasound image on the right shows an 11-week fetus with a normal nuchal translucency measurement.
First trimester screening is a prenatal test that offers early information about a baby's risk of certain chromosomal conditions, specifically, Down syndrome (trisomy 21) and extra sequences of chromosome 18 (trisomy 18).
First trimester screening, also called the first trimester combined test, has two steps:
- A blood test to measure levels of two pregnancy-specific substances in the mother's blood — pregnancy-associated plasma protein-A (PAPP-A) and human chorionic gonadotropin (HCG)
- An ultrasound exam to measure the size of the clear space in the tissue at the back of the baby's neck (nuchal translucency)
Typically, first trimester screening is done between weeks 11 and 14 of pregnancy.
Using your age and the results of the blood test and the ultrasound, your health care provider can gauge your risk of carrying a baby with Down syndrome or trisomy 18.
If results show that your risk level is moderate or high, you might choose to follow first trimester screening with another test that's more definitive.
Why it's done
First trimester screening is done to evaluate your risk of carrying a baby with Down syndrome. The test also provides information about the risk of trisomy 18.
Down syndrome causes lifelong impairments in mental and social development, as well as various physical concerns. Trisomy 18 causes more severe delays and is often fatal by age 1.
First trimester screening doesn't evaluate the risk of neural tube defects, such as spina bifida.
Because first trimester screening can be done earlier than most other prenatal screening tests, you'll have the results early in your pregnancy. This will give you more time to make decisions about further diagnostic tests, the course of the pregnancy, medical treatment and management during and after delivery.
If your baby has a higher risk of Down syndrome, you'll also have more time to prepare for the possibility of caring for a child who has special needs.
Other screening tests can be done later in pregnancy. An example is the quad screen, a blood test that's typically done between weeks 15 and 20 of pregnancy. The quad screen can evaluate your risk of carrying a baby with Down syndrome or trisomy 18, as well as neural tube defects, such as spina bifida. Some health care providers choose to combine the results of first trimester screening with the quad screen. This is called integrated screening. This can improve the detection rate of Down syndrome.
First trimester screening is optional. Test results indicate only whether you have an increased risk of carrying a baby with Down syndrome or trisomy 18, not whether your baby actually has one of these conditions.
Before the screening, think about what the results will mean to you. Consider whether the screening will be worth any anxiety it might cause, or whether you'll manage your pregnancy differently depending on the results.
You might also consider what level of risk would be enough for you to choose a more invasive follow-up test.
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Risks
First trimester screening is a routine prenatal screening test. The screening poses no risk of miscarriage or other pregnancy complications.
How you prepare
You don't need to do anything special to prepare for first trimester screening. You can eat and drink normally before both the blood test and the ultrasound exam.
What you can expect
First trimester screening includes a blood draw and an ultrasound exam.
During the blood test, a member of your health care team takes a sample of blood by inserting a needle into a vein in your arm. The blood sample is sent to a lab for analysis. You can return to your usual activities immediately.
For the ultrasound exam, you'll lie on your back on an exam table. Your health care provider or an ultrasound technician will place a transducer — a small plastic device that sends and receives sound waves — over your abdomen.
The reflected sound waves will be digitally converted into images on a monitor. Your health care provider or the technician will use these images to measure the size of the clear space in the tissue at the back of your baby's neck.
The ultrasound doesn't hurt, and you can return to your usual activities immediately.
Results
Your health care provider will use your age and the results of the blood test and ultrasound exam to gauge your risk of carrying a baby with Down syndrome or trisomy 18. Other factors — such as a prior Down syndrome pregnancy — also might affect your risk.
First trimester screening results are given as positive or negative and also as a probability, such as a 1 in 250 risk of carrying a baby with Down syndrome.
First trimester screening correctly identifies about 85 percent of women who are carrying a baby with Down syndrome. About 5 percent of women have a false-positive result, meaning that the test result is positive but the baby doesn't actually have Down syndrome.
When you consider your test results, remember that first trimester screening indicates only your overall risk of carrying a baby with Down syndrome or trisomy 18. A low-risk result doesn't guarantee that your baby won't have one of these conditions. Likewise, a high-risk result doesn't guarantee that your baby will be born with one of these conditions.
If you have a positive test result, your health care provider and a genetics professional will discuss your options, including additional testing. For example:
- Prenatal cell-free DNA (cfDNA) screening. This is a sophisticated blood test that examines fetal DNA in the maternal bloodstream to determine whether your baby is at risk of Down syndrome, extra sequences of chromosome 13 (trisomy 13) or extra sequences of chromosome 18 (trisomy 18). Some forms of cfDNA screening also screen for other chromosome problems and provide information about fetal sex. A normal result might eliminate the need for a more invasive prenatal diagnostic test.
- Chorionic villus sampling (CVS). CVS can be used to diagnose chromosomal conditions, such as Down syndrome. During CVS, which is usually done during the first trimester, a sample of tissue from the placenta is removed for testing. CVS poses a small risk of miscarriage.
- Amniocentesis. Amniocentesis can be used to diagnose both chromosomal conditions, such as Down syndrome, and neural tube defects, such as spina bifida. During amniocentesis, which is usually done during the second trimester, a sample of amniotic fluid is removed from the uterus for testing. Like CVS, amniocentesis poses a small risk of miscarriage.
Your health care provider or a genetic counselor will help you understand your test results and what the results mean for your pregnancy.
By Mayo Clinic Staff
Frequently asked questions about biochemical screening of pregnant women
What tests are performed on pregnant women?
Currently, two main types of tests are recommended for pregnant women in St. Petersburg:
- analysis for PAPP-A and beta-hCG in the period of 9-13 weeks
- analysis for AFP and hCG.
Should I do a “triple test”?
Some private laboratories use the so-called “triple test”, using kits that, in addition to AFP and hCG, have added the determination of the concentration of another hormone - unconjugated estriol. According to modern data, its assessment for clarifying the risks of fetal chromosomal pathology has too little weight and is highly dependent on many other factors of the woman's condition, which is not significant for calculating risks for fetal chromosomal pathology. If the results of the “double” test reveal an increased risk for you, it is better to contact a geneticist and understand the situation, taking into account a professional clinical assessment of the test results.
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How important is it to accurately indicate the weight of a pregnant woman when taking blood for “fetal proteins”?
Each woman's weight must be recorded on the examination referral. In the absence of such information, the risk can be calculated "according to the average" weight of pregnant women in this period - 60 kg.
All women are different - there are pregnant women weighing 45 and 145 kg. For a more accurate assessment of the results, an amendment is introduced in accordance with the "weight category". But absolute accuracy is not required here - individual grams will not change the calculations. An individual approach is important. Therefore, we always measure a woman's weight before taking tests. nine0005
I took a blood test for fetal proteins, as the doctor prescribed them immediately after taking them, now I'm worried, so I had a hearty breakfast in the morning. Will this affect the outcome of the study? Can I retake blood on an empty stomach?
Don't worry! Unlike most "adult" tests that are sensitive to food intake, the measurement of the amount of any proteins entering the mother's blood from the fetus is not dependent on the time of the meal.
The most important thing here is to know exactly the gestational age established by ultrasound. It makes no sense to retake the analysis. And it is very important for pregnant women to eat breakfast and continue to eat more often during the day than usual. nine0005
In clinics where an individual approach to the examination of pregnant women is possible, and of course, in our Center for Fetal Medicine, blood for screening tests can be donated throughout the working day.
Which test is better - PAPP-A and beta-hCG or AFP and hCG?
At present, the first one has the absolute advantage. It has been proven that it is more specific for assessing risks for chromosomal pathology, including Down syndrome. Its important advantage is that it is carried out in the first trimester, you can donate blood from the age of 9weeks of pregnancy (determined by the size of the fetus on ultrasound). The most optimal terms for this analysis are 9-12 weeks. A study period of up to almost 14 (13 weeks 6 days) is allowed, but the reliability of the risk assessment will be lower.
If you have completed a full first trimester test, performed an ultrasound and received a conclusion from a geneticist that the fetus is at low risk for chromosomal abnormalities, testing for AFP and hCG is not worth it.
In special cases, after the first screening, a test for AFP and hCG is prescribed as an additional test on the recommendation of a geneticist. nine0005
If you missed the first screening test, then, of course, you need to donate blood at least for the second one within 15 to 18 weeks.
I would like to emphasize that, on the recommendation of international experts in prenatal diagnosis, analysis for PAPP-A and beta-hCG in a period of 9-12 weeks is recommended for all pregnant women at any age.
I went through the IVF procedure and used a donor cell, because my cells do not mature at the age of 46. Now 12 weeks. How do I correctly pass a biochemical test? nine0004
You urgently need to donate blood for PAPP-A and beta-hCG and perform an ultrasound.
From your age, the IVF procedure itself does not change the amount of proteins. And the risk "by proteins" will be assessed depending on certain concentrations.
But the computer program calculates the "combined" risks - by proteins, by ultrasound and by the age of the woman, more precisely, by the "age of the egg." Accordingly, for this analysis, the age of the egg donor must be indicated in the calculation referral. If you do not know it exactly, you can calculate by low age risk, since all donors have age restrictions for participating in the IVF program. If you have already been calculated according to your age, don't worry, we can reassess the risks taking into account real data and issue you a Medical Genetic Conclusion based on the results of prenatal studies. nine0005
Doctors of the Fetal Medicine Center are one of the leading specialists in prenatal diagnostics, candidates of medical sciences, doctors of the highest categories with a narrow specialization and extensive experience in prenatal medicine.
All ultrasound examinations in the center are carried out according to the international standards FMF (Fetal Medicine Foundation) and ISUOG (International Society for Ultrasound in Obstetrics and Gynecology).
Ultrasound doctors have international certificates from the Fetal Medicine Foundation (Fundamental Medicine, UK), which are are confirmed annually.
We take care of the most complex cases and, if necessary, it is possible to consult with specialists from King's College Hospital, King's College Hospital (London, UK).
The pride of our Centers - modern and high-tech medical equipment from General Electric: expert-class ultrasonic devices Voluson E8 / E10
The capabilities of these devices allow us to talk about a new level of information content. nine0005
To make an appointment and get an expert opinion of our ultrasound specialists, you can call the single contact center +7 (812) 458-00-00
Screening for the detection of congenital fetal diseases during pregnancy
Category: Reminders for the population .
Pregnancy screening is a whole range of studies that allows parents and doctors to get the most complete information about the health of an unborn baby. Screening reveals many congenital and physical characteristics. How and when is pregnancy screening done? nine0002 What is pregnancy screening and why is it done
Screening during pregnancy is a complex of examinations, which includes ultrasound and biochemical analysis of venous blood for hormones. As a rule, screening is carried out three times - in the first, second and third trimester.
Early detection of pathologies is very important. This makes it possible to start treating genetic diseases as early as possible and, if not completely cure them, then at least stop the symptoms as much as possible. If the doctor notices any abnormalities during the examination, the pregnancy is monitored especially carefully, which makes it possible to prevent the development of complications or premature birth.
If the detected pathologies turn out to be too severe and incompatible with life, the doctor will refer the patient to terminate the pregnancy for medical reasons. nine0005
Pregnancy screening is harmless for both mother and baby. This is a fairly accurate study, although it should be clearly understood that it does not give a 100% guarantee. The accuracy of screening depends on many factors - the professionalism of the researchers, the woman's compliance with the rules for preparing for the examination, and other factors.
First pregnancy screening
The first screening during pregnancy is carried out between the 11th and 13th weeks. It makes no sense to undergo this examination earlier - before the 11th week of pregnancy, many indicators are practically indeterminate. nine0005
The study includes two medical tests - an ultrasound and a blood test.
ultrasound
With the help of ultrasound, the doctor determines the exact gestational age, evaluates the baby's physique, its dimensions (head circumference, limb length, height), the work of the heart muscle, the symmetry of the brain, the volume of amniotic fluid, the structure and size of the placenta, as well as the condition and tone of the uterus.
For each of these parameters, there are normal indicators with which the doctor will compare the results. For an 11-13 week pregnancy, these rates are:
- KTP (coccygeal-parietal size, that is, the length of the fetus from the crown to the tailbone) is 43–65 mm. If this figure is more than normal, then the child will be large. A downward deviation indicates slow development (the reason for this state of affairs is often a hormonal imbalance or infectious diseases suffered by the expectant mother), genetic pathologies or fetal death (in this case, the heart will not be auscultated). However, this may also be due to a banal mistake in determining the timing of pregnancy. nine0111
- BDP (biparietal size, that is, the distance from the temple to the temple) - 17-24 mm. A high BDP means a large fetus, but only on the condition that all other indicators say the same. Otherwise, we can talk about a herniated brain or hydrocephalus. Low BDP indicates slow brain development.
- TVP (collar space thickness) - 1.6–1.7 mm. Deviation from this norm (TVP above 3 mm) is considered a sign of some severe chromosomal pathologies - Down syndrome, Edwards syndrome, etc. However, one should not panic ahead of time - no one will make such a serious diagnosis only on the basis of TVP. To confirm, you need to take a blood test for hormones and take a biopsy of the outer dense shell of the embryo for further research. nine0111
The length of the nasal bone is 2–4.2 mm. Too small a nose bone can indicate pathology or simply that the baby's nose will be snub-nosed. HR (heart rate) - 140-160 beats per minute. A small (up to 40 beats per minute) deviation in one direction or another is considered a variant of the norm.
The size of the chorion, amnion and yolk sac. The chorion is the outer shell of the fetus, which will eventually become the placenta. If it is located on the lower wall of the uterus, they speak of chorion previa. This is a potentially dangerous situation, fraught with miscarriage, and in this case, bed rest is recommended for the pregnant woman.
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The amnion is the inner membrane that holds the amniotic fluid. The normal volume of amniotic fluid at 11–13 weeks is 50–100 ml.
The yolk sac is an embryonic organ that, in the first weeks of a fetus's life, plays the role of some internal organs that will be formed later. By the time of the first screening, the yolk sac should practically disappear (then the examination form will indicate “not visualized”). If its size is about 6 mm, then the fetus may have certain pathologies. nine0005
Cervix. Normally, its length by the time of the first screening is 35–40 mm. A shorter cervix means a risk of preterm labor.
Ultrasound is performed in two ways - transabdominal, in which the sensor of the ultrasound machine is located on the abdomen, and transvaginal, in which it is inserted into the vagina. Transvaginal ultrasound provides more complete and accurate information, but it is usually performed only in the first trimester. This method is usually used when examining overweight women, since the fat layer in the abdomen does not allow the fetus and uterus to be examined in detail.
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It is necessary to properly prepare for an ultrasound. Before a transabdominal ultrasound, it is advised to drink about a liter of water so that the bladder is full at the time of the examination - then the uterus will shift slightly towards the abdomen and the picture will be clearer. With transvaginal ultrasound, the degree of fullness of the bladder does not matter, however, before the examination, it is better to go to the toilet - it will be more comfortable. Before the examination, you need to take a shower or freshen up with wet wipes. The accumulation of gases can distort the results of ultrasound, no matter what method it is carried out. Therefore, expectant mothers suffering from flatulence are advised the day before the examination to take remedies for flatulence and not eat anything that produces gas. nine0005
Blood test
Biochemical screening, also called a dual test, is done to determine the level of two hormones (hence the name) - free b-hCG and PAPP-A.
- b-hCG (human chorionic gonadotropin) begins to be produced from the first days of pregnancy. Its amount gradually increases until about the 9th week, and then begins to gradually decrease. On average, for a period of 11–13 weeks, 50,000–55,000 mIU / ml is considered the norm. An elevated level of hCG may indicate a multiple pregnancy, or, in the worst case, genetic pathologies of the fetus or the presence of diabetes in the mother. Reduced hCG is typical of miscarriage, ectopic pregnancy, fetal death, or certain malformations (Patau syndrome and Edwards syndrome). nine0111
- PAPP-A is an A-plasma protein. The content rate for a period of 11–13 weeks is 0.79–6.01 mU / l. Low PAPP-A is a sign of chromosomal pathologies such as Down syndrome and Edwards syndrome, fetal death and miscarriage, fetal malnutrition (underweight) and preeclampsia.
- A high PAPP-A is a sign of multiple pregnancies, large fetuses, or a low placenta.
In order for the blood test to give the most accurate information, it must be taken on an empty stomach, at least 8 hours after the last meal.
2-3 days before the analysis, you should refrain from fried, fatty, spicy, smoked foods, chocolate, nuts, seafood. It is also recommended not to have sexual intercourse. All this is not so significant, but it can affect the result in one way or another. nine0005
Second pregnancy screening
The second screening during pregnancy is carried out at 16-20 weeks. Like the first one, it consists of the same two stages - ultrasound and blood test.
ultrasound
This time, the doctor determines not only the size, but also the position of the fetus and its bone structure, the condition of the internal organs and the place of attachment of the umbilical cord, as well as the volume of amniotic fluid. Here are the approximate main indicators of the norm for a period of 16-20 weeks:
- BPR - 26–56 mm.
- DBK (length of the femur) - 13-38 mm.
- DPC (length of the humerus) - 13-36 mm.
- OG (head circumference) - 112-186 mm.
IAF (amniotic fluid index, that is, the volume of amniotic fluid) - 73-230 mm. Oligohydramnios can adversely affect the condition of the child's bone structure and the development of his nervous system.
Localization of the placenta. There is some risk only when the placenta is located on the anterior wall of the uterus - with such localization, detachment of the placenta is possible. nine0005
Umbilical cord. One of the most important parameters is the place of attachment of the umbilical cord. Marginal, split or sheath attachment is fraught with fetal hypoxia and difficulties during childbirth, often it becomes an indication for caesarean section. The umbilical cord is fed through 2 arteries and 1 vein, although sometimes only one artery is available. This can cause fetal hypoxia, heart disease, disorders in the child’s cardiovascular system, and cause a baby’s low body weight. However, if all other analyzes and examinations do not show deviations from the norm, you should not worry.
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Cervix. The length of the cervix at this time should be 40–45 mm. A short cervix means a threatened miscarriage.
Visualization. Unsatisfactory visualization can be caused both by the peculiarities of the position of the fetus or the excess weight of the expectant mother, and by edema or hypertonicity of the uterus.
Blood test
As during the first screening, during the second, a blood test for b-hCG is taken, the level of free estriol and AFP is also checked. Here are the norms for their content at the 16th-20th weeks of pregnancy:
- b-hCG - 4.67-5-27 ng / ml.
- Free estriol is a hormone whose level can be used to judge the state of the placenta. The norm is 1.17–3.8 ng / ml. Elevated estriol is characteristic of multiple pregnancy or a large fetus. Reduced - for threatened miscarriage, placental insufficiency, anencephaly and Down's syndrome.
- AFP is a protein that is produced in the gastrointestinal tract of the fetus.
Norm - 15-27 U / ml. A slightly lower AFP may mean that the gestational age was determined incorrectly (slightly underestimated). If the AFP is very low, the cause may be Edwards or Down syndrome, the threat of miscarriage or fetal death. High AFP is characteristic of neural tube pathologies, esophageal atresia, Meckel's syndrome. High AFP is also possible in women who have had an infectious disease during pregnancy. nine0111
Third pregnancy screening
The third screening during pregnancy is carried out at the 30th-43rd week. Based on the results of this screening, the doctor decides on the need for a caesarean section or the possibility of a natural birth. The basis of the third screening is the same ultrasound. Sometimes dopplerography is prescribed - a study of the work of blood vessels. Here are the approximate norms for a given gestational age:
ultrasound
nine0109 The thickness of the placenta is 23.
