Determination of pregnancy by a general blood test. Determining pregnancy by hCG level

Currently, there are several methods that allow you to quickly and accurately determine the presence of pregnancy. One of the most popular of them are pregnancy tests sold in pharmacies. However, a more accurate result can be obtained by conducting a pregnancy blood test based on determining the level of the hCG hormone.

What is HCG

A special hormone that is not produced in the body of a man and a non-pregnant woman is human chorionic gonadotropin, called hCG for short. When pregnancy occurs, the membranes of the fetus, namely the chorion, begin to release the specified hormonal substance. The presence of gonadotropin in the blood allows you to accurately determine pregnancy by a blood test.

It is for this reason that this study is called a blood test for pregnancy.

Does a blood test show early pregnancy?

As follows from the instructions for a standard pharmacy test based on the presence of chorionic hormone in the urine, it is possible to obtain a reliable result on it no earlier than the first day of delay. You can determine pregnancy by a blood test already on the tenth day from the moment of fertilization, that is, approximately one week before the next planned menstruation. Thus, the possibility of carrying out an earlier diagnosis when taking a blood test for pregnancy and the period at which this study can be carried out are the undoubted advantages of this method over the “usual” test from a pharmacy. However, such an analysis was created not only to ensure that impatient parents know the desired results as quickly as possible.

Pregnancy blood test: normal hCG levels

Many women are wondering what hCG indicators should be at a particular stage of pregnancy. It should be noted that each of these terms has a fairly wide range of normal values, which is why it is not always possible to find out how well the embryo develops. However, when taking a blood test for pregnancy twice or more, you can almost always get the correct results. In some situations, it is impossible for expectant mothers to conduct any other examinations, except for suggesting a blood test for pregnancy, therefore, in such situations, one has to rely only on the results obtained from a blood test for hCG.

The unit of measure for the level of chorionic hormone is honey/ml. For men and women who are not currently expecting a baby, the hCG value is less than 5. For pregnant women, the rate of this hormone is determined for each period of pregnancy separately.

Compared with the baseline, which is less than 5 mU / ml, the content of chorionic hormone in the blood of a woman carrying a child will always be increased. And in some cases, the level of this hormone increases even more than it should be at the corresponding gestational age. A significant increase in the level of chorionic gonadotropin occurs with multiple pregnancy female patients. In this case, the value of this hormone can exceed 1.5-2 times and even more than the normal level of hCG for each period of pregnancy.

Such a study as a blood test for hCG does not need to be carried out in every case of pregnancy. If the gestation proceeds safely, then there is no need to take this analysis. However, in any case, performing a blood test for hCG provides diagnostic information, on the basis of which it is possible to identify possible violations in the development of the fetus, select the necessary treatment, and, with the normal development of the child, please future parents with such information.

Today, the most popular way to self-diagnose pregnancy is to buy a test at a pharmacy, the mechanism of action of which is based on a woman's urine test. However, the sensitivity of the tester is quite low: resorting to the test as the only source of information about a possible "interesting situation", a woman runs the risk of being misinformed. Other homegrown methods are a frivolous, if not a dangerous way. Most reliable method in the arsenal of modern medicine is the determination of the onset of pregnancy by a blood test.

The method of determining pregnancy by blood test is based on determining the level of "pregnancy hormone" in the woman's blood. A special pregnancy hormone is called human chorionic gonadotropin (hCG), produced by the cells of a special shell of the embryo - the chorion. If chorionic tissue is present, there is pregnancy. This makes the definition of pregnancy on early dates possible by blood test: already a week after conception, the result of the analysis for the level of hCG will be guaranteed positive. Normally, the level of hCG in the blood serum of a healthy non-pregnant woman is from 0 to 15 mU / ml.

In addition to determining pregnancy, this analysis is prescribed to identify fetal pathologies (in the period from the 14th to the 18th week of pregnancy). You can always make a reliable analysis of hCG at any time convenient for you and even urgently at the Center for Traditional Obstetrics and Family Medicine.

How to take a blood test for hCG

Traditionally, pregnancy is determined by a blood test on the eighth day after the woman's intended conception, but not earlier than after 3-5 days of delayed menstruation. For this, in the morning, on an empty stomach, venous blood is taken. If you plan to take the test at another time of the day, then you must stop eating 4-6 hours before the procedure.

If you are taking medications or hormones, be sure to tell your gynecologist or nurse about this. To clarify the results, the test can be repeated after a few days. More detailed recommendations on preparing for the analysis will be given to you by the gynecologist of the Center chosen by you.

Whether you're planning on having a baby or not, missed periods are always a source of stress for women. And the first thing to do in this case is to determine whether conception has occurred, namely, to take pregnancy tests. The most common and accessible way are home rapid tests. But, as practice shows, the results are often inaccurate. In order not to make an endless number of attempts, doctors recommend resorting to a more reliable method - taking a blood test for pregnancy, the result of which is discarded all further doubts.

What is this study? What does it show? How to determine pregnancy by a blood test? When and how to submit it? Let's figure it out.

Laboratory blood tests to determine conception reveal a special hormone in a woman's body - human chorionic gonadotropin (hCG). It is produced by the shell of the embryo - the chorion, and begins to be released into the body from the first hours of fertilization of the cell. And if this hormone is present in the body, there is conception. At the same time, its concentration in the blood of a pregnant woman doubles every two days. And the greatest value its level reaches 8-, after which there is a decrease.

Express pregnancy tests also determine the level of hCG, showing that very second strip, but the concentration of this hormone in the urine is much lower and increases at a much slower pace. Therefore, a more accurate study to determine fertilization is considered to be a blood test, which is able to detect conception as early as 2-5 days after fertilization. While the test strips - only a week later.

Did you know? The concentration of hCG in the blood serum is significantly higher than in the urine, almost 2 times.

For normal development The fetal level of this hormone in a woman is very important, because it also indicates the success of the growth and development of the fetus, therefore it is necessary to monitor it throughout the entire period of bearing a child.

What exactly does it show

Also, the hormone hCG helps to predict the duration of pregnancy, based on the level of its concentration in the blood.

It is very important to monitor its level throughout the entire period of expectation of the child, as it can indicate possible pathologies in the development of the fetus. The first screening is done in the period from the 11th to the 11th, where the PAPP-A plasma protein is also examined and an ultrasound scan of the embryo is performed, which determines the presence of chromosomal abnormalities in the fetus. Repeated studies, the second screening, are carried out at 16-. The data obtained are not the final diagnosis, and only determine the risk group and prescribe additional studies. It should also be noted that determining the level of hCG is only a part of the study, which in itself is not a reliable screening.

Deviations from the norm can appear with such serious problems as freezing or ectopic pregnancy, the threat of disruption (in the early stages), pathologies in the development of the fetus, multiple pregnancy, etc.

Important! In non-pregnant women, a high level of hCG may indicate a number of oncological diseases (tumors of the mammary glands, ovaries, gastrointestinal tract, etc.).

When can I take the test and how is the procedure?

A blood test for hCG levels can already be taken if menstruation is delayed by 3-5 days. In the case when the exact date of conception is known, after a week you can go to the laboratory to confirm or deny the fact of conception. Be prepared to repeat the procedure at least twice in 2 days, preferably at the same time and in the same laboratory, to monitor growth dynamics.

An analysis is given in the morning on an empty stomach by taking blood from a vein. If you take it during the day, then the day before it is recommended to refrain from food for 4-6 hours. In the case of taking hormonal drugs, it is necessary to warn the doctor about this. It is also recommended to exclude severe physical activity, nervous shocks and physiotherapy procedures a day before visiting the laboratory.

Deciphering the results during pregnancy

The first thing you should pay attention to when deciphering the results of laboratory tests is the units of measurement. They can be as follows - honey / ml, U / lm, mIU / ml, mIU / ml. There is no need to specifically translate one into the other, they are one and the same, and there is an equal sign between them. But the indications of the norm should be given priority attention, since each laboratory will have its own. This depends on the sensitivity of the methods used.

It is also necessary to know that during multiple pregnancy, the hCG indicator will be increased by a multiple of the number of embryos.
The level of this hormone until the 10th week is growing rapidly every 7 days, after which it stabilizes for a while and begins to gradually decrease until the moment of delivery.

tables hCG norms by week, widely distributed on the Internet, clearly demonstrate such dynamics.

On the 1st-2nd week, the level of the hormone is small and averages from 50 to 300 mU / ml. In the next 7 weeks, it continues to grow rapidly, reaching its peak at the 7-8th week, when the upper limit of the norm is 200,000 mU / ml. And for the next two trimesters of waiting for the child, there is a gradual decrease to 10,000 - 60,000 mU / ml at the time of delivery. In this case, to determine the period, the date of the last menstruation is taken, and not the date of conception.

Did you know? The hCG hormone is also present in the male body, stimulating the production of sex hormones and sperm. Its level is about 2 mU/ml.

Remember - only your attending physician can give the most reliable decoding of the data. Because the normal range is quite wide and a number of individual factors must be taken into account. And some indicator for one woman may be a suspicion of pathological processes, and for another, it may well fit within the normal range. Therefore, only a doctor who knows all the features of your body is able to draw conclusions and prescribe the next steps.

Deviation from the norm: what is dangerous and what to do?

In a laboratory study, two variants of deviation from the norm are possible - hCG is above and below the norm.

A low indicator of this hormone in a blood test for pregnancy in the early stages indicates quite dangerous and pathological conditions:

hormonal failure in a woman;
ectopic pregnancy;
intrauterine fetal death;
pathologies in the development of the embryo.

On the later dates this may be evidence of a baby being overwhelmed. In any case, the real cause is determined by the doctor, based on additional research.

Elevated hCG can be with:

multiple pregnancy;
taking hormonal drugs;
diabetes in a woman;
toxicosis;
gestose;
developmental pathologies of the embryo.

When receiving results, do not jump to conclusions. Deviations from the norm in any direction can often be caused by an incorrect determination of the gestational age. And only the doctor decides on further actions. And the first thing he prescribes is a second study, because it is very important to monitor the level of this hormone in dynamics. Also, for further conclusions, additional diagnostics are carried out, the basis of which is ultrasound.

Can the analysis be wrong?

Like any study, hCG analysis carries the risk of error. Such results are called false-negative (if conception occurred, but the analysis did not reveal this) and false-positive (there was no fertilization, but the analysis shows the opposite). The probability of the first increases at too early blood donation, when the fetal egg has not yet attached to the uterine wall and the hormone level is too low. The cause may also be late ovulation, ectopic pregnancy, a sudden change hormonal background. False positive results may occur when taking hormonal drugs, which include hCG, as well as in serious tumor diseases.

Although very rare (with a probability of less than 2%), erroneous analysis data is obtained when the procedure for collecting material in the laboratory was violated, or an error in determining the gestational age.

In any case, if you have any doubts, consult your gynecologist and go through a number of necessary additional studies.

Other diagnostic methods

The simplest and most familiar home express tests work on the same principle, they only detect the level of hCG in the urine, where its concentration is much lower. The modern rapid test has sufficient sensitivity, and most often gives reliable results about the presence of conception. In addition, its availability and ease of use is an undeniable advantage. It is with his help that most women get rid of doubts, and a blood test only finally confirms the result. Therefore, these two methods perfectly complement each other.

But the greatest accuracy in determining conception gives ultrasound. Already from the 4th week of the term, the intravaginal sensor visualizes a fetal egg about 2 mm in size. And later (from the 5-6th week) it makes it possible to confirm the formation of the yolk sac, the attachment of the embryo to the uterine cavity and the viability of the fetus. Together, the level of hCG and ultrasound make it possible to identify all possible pathologies in the early stages.

Video about a blood test for pregnancy

The following video discusses in detail the analysis for hCG, as well as its decoding:

Many women, especially those who want to become a mother, claim that they feel when the magical moment of conception occurs. Others notice only those changes in the body that are hard to ignore (delayed periods, for example). Both those and others eventually resort to modern research methods, the first on the list of which are home tests that have confirmed their effectiveness, and in 90% of cases they give the correct result. But to get rid of all doubts, it is necessary to do two or even more express analysis, or you can not waste time and money, but immediately go to the laboratory and take a blood test. After all, only after it you can say with 100% certainty "I am a future mother."

How did you find out about your pregnancy? When and how many times during the period of gestation was the level of hormones monitored? Write about your experience in the comments.

2 123

A modern rapid test, which is sold in a pharmacy, is a cheap, affordable and reliable way to find out about pregnancy. However, there are situations when a woman wants to know the result before she has a delay or if this is required by medical indications. Determination of pregnancy by blood test is the most informative and accurate method of diagnosing.

What is a blood test based on?

If conception has occurred, then the shell of the fertilized egg stimulates the production of a special hormone - human chorionic gonadotropin. The hCG hormone is also called the "pregnancy hormone". It is it that is determined both in conventional express tests and in a biochemical blood test. If fertilization does not occur, the hormone levels will not exceed the norm.

If the usual pharmacy tests allow you to identify the special condition of a woman from the first day of delay, then an analysis to determine pregnancy by hormone can be done even on the 6th day after conception, that is, a week earlier. However, for more reliable result it is recommended to determine pregnancy by blood at least after 3 days of delay.

HCG levels in a non-pregnant woman range from 0-10 mU / ml. From the first hours of pregnancy, the shell of a fertilized egg begins to produce a hormone and the values increase significantly, reaching a maximum by 12 weeks.

What is the analysis for?

A blood test to determine pregnancy is done in the following cases:

The need for earlier diagnosis of fertilization.
Determination of the degree of development of the fetus.
Timely detection of ectopic or missed pregnancy.
Determining the likelihood of a miscarriage.

How to take an analysis

For analysis, venous blood is taken, so doing it better in the morning, on an empty stomach. If blood sampling is done in the evening, it is recommended to refrain from eating 6-8 hours before the procedure. The results may be distorted if a woman takes some medications in parallel. You need to warn the doctor about this.

If the analysis is done before the onset of the delay, then the doctor will compare not only the absolute indicator of the concentration of the hormone, but also the dynamics of its change. With early diagnosis, the analysis will have to be repeated after 3 days. It is recommended to do repeated blood sampling in the same laboratory.

The analysis is done quite simply, you can order it in any private laboratory and even public clinics. The results are ready in 1-2 days. They need to be taken to a gynecologist so that he draws the right conclusions.

HCG norms

The sensitivity of pharmacy express tests starts from 15 mU / ml. If the hCG values are below this limit, only the control test strip will react, and the indicator will show a negative result.

In the first week of embryo development, the hormone level increases several times, and a blood test will help determine not only the fact of the increase, but also the quantitative content of the hormone.
In the third or fourth week, hCG can reach 1-30 thousand mU / ml.
The period of two-month development of the embryo is characterized by extremely high levels of the hormone. Its concentration can reach 30-200 thousand mU / ml.
Peak concentrations are recorded at 11-12 weeks, then the level of hCG gradually decreases.
In the second trimester, the level of the hormone is in the range of 20-60 thousand mU / ml.
In the third trimester, the values fall even lower - up to 6-10 thousand units. However, 1-2 weeks before the birth, the level of the hormone jumps up again.

Such wide ranges of values are explained by the individual course of each pregnancy. In addition, each laboratory conducts analysis based on a specific research method. Therefore, it is important to compare the results obtained not with generally accepted indicators, but with laboratory standards.

A woman is advised to wait for a delay in menstruation, since with an early analysis, the concentration of hCG may be insignificant. Then the doctor prescribes a second analysis to get the result in a few days and see the dynamics of the process. With an accomplished pregnancy, the numbers may differ several times, which will confirm the special condition of the woman.

By determining pregnancy by a blood test, you can not only find out the good news about its onset, but also track how well the fetus develops. For each week of pregnancy, there are boundaries for the normal concentration of the hormone. Deviation from these norms can be a symptom of incipient problems.

Causes of deviation from the norm

A blood test is the only way to determine the exact concentration of the hormone and draw a conclusion about the course of pregnancy. Deviations from the norm are observed in the case of:

Complications during pregnancy, for example, toxicosis.
Diabetes.
Multiple pregnancy.
placental insufficiency.
Wrong deadline.
Fetal pathologies.
A frozen embryo or ectopic attachment.
Premature birth or threatened miscarriage.

Blood test is easy and fast way find out if you are pregnant. Its advantage is that it is possible to control the course of the process by comparing the quantitative indicators of the hormone with the standards and its changes in dynamics. The level of hCG is an important diagnostic criterion for gynecologists in some controversial situations or in complicated pregnancy.

Waiting is always tiring. Therefore, most girls do not get tired of looking for ways to determine pregnancy even before the test confirms it. Some are looking for answers in the literature, others select options on the advice of friends and acquaintances. We offer a selection of the most reliable and effective ways learn about your situation.

100% accurate method: blood test

You can find out about a possible pregnancy by donating blood to human chorionic gonadotropin. The hCG hormone, in other words, the pregnancy hormone, begins to be produced in the woman's body immediately after the fertilized egg is fixed in the uterus.

How to determine pregnancy by blood test? Compare the result obtained and the established norms. Normally, the hCG indicator should not exceed 10. This applies to non-pregnant women and men. After conception has occurred, hormone levels will double every 36 to 48 hours. Therefore, already a week after conception, an increased content of hCG in the blood can be noted.

A blood test for hCG can not only confirm the fact of pregnancy, but also reveal various pathologies in the fetus.

Venous blood is used as an analysis. An important point, is the fact that before the analysis it is necessary not to eat 6 hours.

This study is the most optimal in deciding how to determine pregnancy before a delay. It is often used in in vitro fertilization clinics to control the development of pregnancy at the earliest stages.

When answering the question of when pregnancy can be determined, experts still recommend undergoing this study only on 2-3 days of delayed menstruation. By the way, the analysis is carried out on a paid basis.

HCG in urine: when will it show

The pregnancy hormone can be determined not only in the blood of a pregnant woman, but also in the urine. It should be noted that in this case, you will have to wait a longer time, since the concentration of hCG in the urine is several times lower than in the blood.

The urine method is the basis of all rapid pregnancy tests. Making them is quite simple, and the result is obtained with high accuracy. When can it be done? Depends on the sensitivity of the test. You can find out this indicator by studying the instructions for the test.

Most pregnancy test strips have a sensitivity of 20–30 mIU/mL.

To understand on what day after conception pregnancy can be determined, you will have to delve into female physiology. A fertilized egg is not immediately fixed in the uterus. On average, this takes about 3 more days, although sometimes this period lasts up to 10 days. Only after this will the growth of chorionic gonadotropin begin. As test manufacturers assure, it is advisable to test for the 3-4th day of a delay in menstruation to get the most accurate result.

How to do the test correctly:

Collect urine in a specially prepared clean container.
Open the protective packaging of the dough and lower it into the collected material up to the special mark.
Hold for 5 seconds.
Lay on a flat horizontal surface.

You can increase the effectiveness of the test if you do it using morning urine. It is at this time that it contains the maximum content of hCG. First, a test line appears on the test, it will tell you that all the conditions have been met. In case of pregnancy, another similar strip will be visible next to it.

It should be noted that even a mild second strip can indicate the presence of pregnancy. If this appears, then it is better to wait 2 days and do the test again.

Trust in the hands of experts

If the test showed a positive result or the woman has suspicions of pregnancy, you should immediately contact a specialist. First, it can give reliable information about the situation. Secondly, it will help to avoid health problems and identify pathologies at an early stage.

How a gynecologist determines pregnancy during examination:

Examination of the external genitalia.
Checking the internal genital organs.
Breast assessment.
Condition of the skin.

The first thing the specialist will pay attention to is appearance labia. Venous plethora is one of the symptoms of pregnancy. It is characterized by the following manifestations:

change in lip color. They acquire a bluish tint;
change in consistency. The labia have a denser texture;
drop in temperature. The external genitals become cool;
puffiness.

It is possible to determine pregnancy during examination only after 4-5 weeks from conception. Until this time, the signs may be the same as those that characterize close periods.

After that, the doctor performs an examination using a gynecological mirror. The onset of pregnancy can be determined:

along the cervix. The body becomes softer, increases in size;
along the vaginal mucosa. It becomes edematous, the surface is smooth, the color is red-violet.

Special attention is paid to the nature of the discharge. Since a smear can also be used to judge a probable pregnancy. Mucous discharge from the vagina in this case becomes transparent, viscous, their number increases. A swab is required for laboratory testing.

The next step is hand inspection. The doctor will feel the uterus through the front wall of the abdomen. The development of pregnancy can also be judged by the breast. It becomes more elastic, painful when touched, increases in size.

What is basal body temperature

The method of determining pregnancy by basal temperature is quite painstaking, it requires attention and strict adherence to the schedule. What is basal body temperature? This is the temperature that is measured in a state of exceptional rest. The measurement site can be the oral cavity or the rectum.

Rectal temperature changes throughout the cycle. This is due to the action of various hormones in the female body. So, the first half of the cycle is called the luteal. In it, the temperature in the rectum does not rise above 36.9 degrees.

Using this method, it is possible with a high probability to determine ovulation at this moment, the basal temperature mark will be at the level of 37.3–37.7 degrees. This is due to the action of the hormone progesterone.

stress, climate change, physical activity and many other factors can greatly affect the accuracy of the results.

Just before the menstruation itself, the temperature drops sharply to 37 degrees. If this did not happen, and menstruation did not occur at the usual time, pregnancy can be assumed.

To get the most accurate results, you should know how to measure basal temperature:

Measurements should be carried out only after sleep, which lasted at least 3 hours.
Reduce movement to a minimum. Therefore, it is better to put a thermometer immediately next to the bed.
The duration of measurements in the rectum is 3 minutes. You can also measure the basal temperature in the oral cavity. This will take 5 minutes.
Do not change the measurement tool.

Measurements must be made from the first day menstrual cycle only in this case it will be possible to judge the reliability of the results.

Pregnancy with menopause: can this be

It is possible to get pregnant during menopause only if the woman's ability to fertilize has not yet completely died out. Indeed, in a full understanding of menopause, childbearing and conception are simply impossible.

With menopause, pregnancy can be suspected by the following signs:

nausea in the morning;
lack of menstruation;
fast fatiguability;
positive pregnancy test.

Pregnancy during menopause is a serious burden on the body. The expediency of its preservation and taking into account all possible risks should be carried out by specialists. But the final decision to preserve or interrupt always lies with the woman herself.

Some resort to the most unexpected and controversial methods of determining pregnancy. Of course, they have a place to be, but it is not recommended to trust them 100%. Since pregnancy can only be determined with high accuracy medical workers using special equipment.

First of all, you should pay attention to early signs pregnancy before missed period:

engorgement of the mammary glands;
nausea in the morning;
sudden change of mood;
rapid decline in strength;
lower back pain;
changes in taste preferences.

Folk methods will also help satisfy curiosity:

Determination by a drop of iodine. To do this, you need to drop iodine into the urine and observe. During pregnancy, a drop of the product remains on the surface and does not spread.
By the pulse on the stomach. The woman lies on her back and puts her hand just below the navel. Approximately 7–8 cm. If a pulsation is noted in this place, then she is possibly pregnant.
Soda and urine. To do this, pour 1 teaspoon of ordinary soda into a container with urine. During pregnancy, the substance calmly sinks to the bottom, without reaction.

Alarm bells: we determine a missed pregnancy

There can be many reasons for the cessation of fetal development. These are chromosomal abnormalities and infectious diseases of the mother. It is very important to determine this phenomenon at an early stage so that the deceased fetus does not begin intoxication of the mother's body.

There are several ways to determine a missed pregnancy before visiting a antenatal clinic:

A pregnancy test shows a weak second line for a long time. If the first test shows a faint second line, the examination should be repeated after 2-3 days. At developing pregnancy the hCG level will rise and the line will become pronounced. If the development of the fetus has stopped, the test results will not change.
A sharp drop in basal temperature. The level of progesterone falls, and hence the body temperature drops.
A strong increase in the number of leukocytes and protein in the urine.

In addition, you should carefully listen to your own body. Problems with the child may indicate.