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Can an ultrasound not show pregnancy? Fetal size by week of pregnancy
Can an ultrasound not show pregnancy? Fetal size by week of pregnancy

There are times when women find out they're pregnant when they're well into their term. There are quite a few ways to confirm a special situation using the analysis of hCG, various tests. But sometimes the methods listed do not always carry reliable information. Can ultrasound not show pregnancy? We will talk about this in this article.

Why do I need ultrasound during pregnancy?

Ultrasound examination

One of the most accurate ways to determine pregnancy is an ultrasound. With it, the doctor can see the fetal egg in the uterine cavity and determine the approximate period.

Ultrasound is divided into types:

  • Transrectal - carried out through the rectum. This procedure does not apply to pregnant women, since it is performed most often on girls who are not sexually active.
  • Transvaginal - done through the vagina, suitable only for women in early pregnancy. It's believed thatexamination by this method is the most reliable.
  • Transabdominal is aimed at examining the pelvic organs, is carried out through the anterior abdominal wall.
  • Combined - combines the last two ultrasound methods, carried out for a complete diagnosis.
  • 3D, 4D - allow you to get a realistic image of the baby. And thanks to the 4D ultrasound method, you can see the movements and even facial expressions of the child in real time. Usually carried out to clarify the condition of the fetus.

What week is pregnancy visible on ultrasound?

Transvaginal ultrasound is commonly used to confirm early pregnancy. Many mothers are tormented by the question: “What week is the pregnancy visible on the ultrasound?” Let's figure it out. This method allows you to determine the fetal egg at 3-4 weeks of pregnancy. At this time, the level of hCG (human chorionic gonadotropin) should be at least 1800 units. This indicator is one of the most important, as it allows you to more accurately determine the presence of pregnancy and its course.

Ultrasound examination

Can a doctor fail to detect pregnancy

But let's get back to the question of whether ultrasound can not show pregnancy. Such cases happen quite often. If hCG is positive, and the ultrasound does not show pregnancy, then in most cases this may indicate an ectopic pregnancy. It is also worth noting that even in the presence of a fetal egg, one cannot be completely sure of pregnancy, since it may be empty. The uzist will be able to confirm the "interesting situation" with confidence only ifif the embryo itself is found. At 3 weeks from conception, the size of the fetal egg is 4 mm. At this time, only it is displayed on ultrasound, and closer to the fifth week, you can find the embryo itself.

Early term ultrasound

Ultrasound for pregnancy in the first weeks is considered uninformative. Moreover, doctors do not recommend it to be carried out in the absence of medical indicators. These indicators include: the threat of miscarriage, problems with fertilization, bleeding, suspected ectopic pregnancy. Experts explain this by the fact that when a fetal egg is attached, the uterus should be at rest, since unnecessary intervention can provoke an abortion. That is why it is advisable to carry out the first ultrasound in early pregnancy no earlier than the fifth week.

Why ultrasound does not show pregnancy: the main reasons

Can an ultrasound not show pregnancy not only in the early stages, but also in the later ones? This also happens in practice. For example, at 10-11 weeks of pregnancy, a doctor may send a woman for an abortion without identifying an “interesting position”, but suspecting an ectopic pregnancy. Why is this happening?

woman holding a picture

We propose to identify a number of reasons:

  • Lack of proper experience and qualifications of a doctor.
  • Due to the anatomical features of the uterus (for example, an unusual shape), the device may not detect a fertilized egg.
  • Pregnancy is too short. The yolk sac, which is part of the fetal egg, the doctor will be able to examine no earlier than the fifth week.That is why before this period it makes no sense to conduct an ultrasound scan in the antenatal clinic.

Everyone can make a mistake, so if such a situation arises, you should not panic, but it is better to double-check: re-analyze for hCG, contact another specialist.

The entire period of pregnancy is very important not only for the woman, but also for the baby himself, because every day he undergoes changes and develops at a tremendous speed. As a rule, the uzist determines the gestational age based on the size of the fetus. Consider the size of the fetus by week of pregnancy by ultrasound

First trimester

First month of the embryo

1. 1 week is counted not from the moment of conception, but from the date of the beginning of the last critical days. It is from this moment that the doctor announces the preliminary date of birth. Such a calculation is made because at the beginning of the next menstruation, an egg is formed, the fertilization of which, with a successful combination of circumstances, occurs in about two weeks. Therefore, it is too early to talk about the size of the fetus.

2. Around the end of the second week, conception occurs. At the gestational age, according to ultrasound, 2.5 weeks of pregnancy, the size of the unborn baby is no more than 0.1-0.2 mm. At this time, the child has not yet acquired human features, but is more comparable to a poppy seed. It is likely that even at 2.5 weeks of pregnancy, the size of the fetus will not be determined, so conducting an examination at this time can be considered a meaningless exercise.

3. The fetus is 5 weeks old, but according to obstetric calculations, we are talking about 3weeks. Earlier we mentioned that gynecologists start counting from the first day of critical days. At this time, the process of movement of the zygote through the fallopian tube to the uterus continues. The fetus is 0.15mm.

4. At the beginning of the 4th week, the zygote reaches the uterus and implants in its lining, which can cause some bleeding. The size of the fetal egg is 1 mm, comparable to a sesame seed.

5. Miscarriages often occur at this time, so at this time, the expectant mother needs to carefully monitor her he alth. Meanwhile, the fertilized egg is growing rapidly, at the 5th week of pregnancy, the size of the fetus reaches 1.25 mm.

6. At week 6, the embryo can already be seen using ultrasound. At this time, he begins to move, but his movements are not yet felt by the mother, since the fetus is very small. Its size is 2-4 mm.

7. At this time, the heart of the embryo beats, the tail gradually begins to disappear, which will finally disappear by the end of the tenth week. The weight of the fetus at this time is 0.8 g, and the size is 4-5 mm, comparable in size to a pea.

8. This week, the fetus reaches 1.6 cm in length, and its weight is already 3 g. At this time, changes occur not only with the unborn baby, but also with his mother. A woman may notice breast enlargement, darkening of the nipples, as well as abdominal pain associated with a rapid increase in the uterus. The pain should pass soon. A baby at 8 weeks pregnant is similar in size to a bean fetus.

9. A nine-week-old embryo develops a swallowing reflex, he already knows how to compress and decompresscams. Pawned systems and organs continue to rapidly form. At this time, the size of the crumbs reaches 2.3 cm, and its weight can vary from 5 to 15 g.

10. From this period, the mother's tummy begins to grow, especially if the pregnancy is not the first. The placenta is formed in the mother's body, thanks to which the baby will receive nutrition. The length of the fetus reaches 3.1 cm, and the weight may remain unchanged. You can compare the crumbs in size with an average plum.

11. During this week, the intestines form in the fetus. Now he already knows how to yawn, turn around, move his legs and arms. But mom can not yet feel his movement, because he is still very small. The size of the crumbs is about 4.1 cm in length, and its weight is 7 g.

12. By this time, the baby has already formed the urinary and circulatory systems. Now the coccyx-parietal size (KTP) reaches 5.4 cm.

13. This week is the last week of the first trimester. As a rule, the first ultrasound is prescribed at this time. The size of the fruit is about 7.4 cm, and the weight is 20 grams.

Second trimester

fetus in the second semester

14. This week starts the second trimester. From this time on, significant external changes appear: the fetus begins to grow hair, eyes converge and facial expressions appear. Now the baby is about 10 cm long and weighs 30 grams.

15. At this time, the fetus is a miniature copy of the newborn. The future baby is growing rapidly, it reaches a length of 11 cm, and a weight of 50 grams. At this time, the size of the fruitcomparable to an avocado.

16. At this time, the mother can feel the first movements of her crumbs. The fetus continues to improve the face, the bladder is actively working and the marigolds are completing their formation. The baby reaches 15 cm in length, and it weighs about 100 grams. You can compare a baby at 16 weeks with a small carrot.

17. At this time, the baby hears sounds, distinguishes between the voices of dad and mom. Now the baby reaches up to 18 centimeters in length and 150 grams in weight. At week 17, the baby is about the size of a medium potato.

18. At this time, an ultrasound scan by a qualified doctor can reveal the sex of the unborn child. During the entire stay in the tummy, the baby has become much stronger, it reaches 20 cm in length and 200 grams in weight. And the size of the fruit is comparable to a medium-sized tomato.

19. Every day the movements of the baby are more and more distinct. Now not only mother, but also other relatives can feel the movements if they put their hand on their stomach. In a week, the fetus gained 30 g in weight and 2 cm in height. The fruit is now comparable in size to a banana.

20. As a rule, at this time, the gynecologist prescribes a second scheduled ultrasound examination. At week 20, the baby already has hair on his head, tiny nails and an expressive face. Its dimensions are about 25 cm, and its weight is approximately 300 g. It is similar in size to a small bunny.

21. Now the fetus reaches 26 cm in length and 350 g in weight. The baby weighs about the same as a large mango.

22. This week, internal organs continue to develop. The growth rate of the fetus slows down a little,because the emphasis is on weight gain. So, the growth of the future baby remains unchanged, but its weight is already 475 grams. The size of the fetus at 22 weeks resembles an egg of an emperor penguin.

23. Now the fetus is growing by leaps and bounds. At this time, its parameters are 500 grams of weight and 30 centimeters in length. The corncob will serve as an analogue for comparison.

24. The fetus is growing rapidly, so in the uterus it becomes cramped every day. The size of the baby at this time is about 30 cm, and its weight has increased by as much as one hundred grams. The baby is now the size of a green coconut.

25. At this time, the development and improvement of the baby continues. Now mom feels active kicks and regular jolts in her tummy. KTR at week 25 is 32 cm, and weight is 700 g.

26. At this time, the rounded shapes of the tummy are clearly visible to others. Now the weight of the baby reaches 800 g, and the height is 33 cm. The size of the fetus is comparable to a head of broccoli.

Third trimester

fetus in trimester

27. This is the final trimester of pregnancy. For six months in the tummy, the baby already knows a lot: sucking fingers, recognizing the voices of parents, recognizing s alty and sweet foods. The baby is growing at a fast pace. At week 27, his weight reaches 900 g, and his height is 34 cm.

28. At this time, a pregnant woman may experience training contractions. The most important thing for a future mother is to be able to distinguish training fights from real ones. As for the baby, now he smells,distinguishes tastes, knows how to see and hear. The KTR of the crumbs is 35 cm, and its weight has reached the mark of one kilogram.

29. By this time, the baby in the tummy should take a head presentation. The baby in the mother's tummy becomes even tighter, so he can no longer tumble as before. The KTR is 37 cm, and its weight has reached the mark of 1.2 kg. By weight, the fruit is comparable to an ostrich egg.

30. This week, the baby’s eyesight is actively forming and the nervous system is developing, and some character traits are also beginning to be laid. The growth of the crumbs can be approximately 37-38 cm, and its weight reaches 1.4 kg.

31. Around this time, the expectant mother needs to undergo a third planned ultrasound. In a week, the baby has grown well and its height is about 40 cm, and its weight is 1.6 kg. A newborn lion cub weighs about the same.

32. At this time, the baby's cheeks are rounded, the skin has acquired a light pink hue, and very soon he will have folds on the arms and legs. The CTE of the fetus is 42 cm, and the weight is 1.8 kg.

33. Fetal indicators at week 33 are as follows: weight - 2 kg, height - 43 cm. By weight, the baby is comparable to a large pineapple.

34. The baby's heart is almost formed. The baby is actively gaining grams, because of this, the mother may notice a decent weight gain, as well as face heartburn and digestive problems. Now the growth of the crumbs varies from 42 to 43 cm, and the weight is 2.1 kg. The size of the fruit is comparable to a melon.

35. Before the expected date of birth, it remains to wait quite a bit, buteven if the child is born earlier, then there is nothing to worry about, since the baby is already physically ready for this. Its activity is significantly reduced due to lack of space in the uterus, but still the mother needs to monitor and count the baby's kicks. The size of the baby at 35 weeks is 46 cm and 2.5 kg, resembling an average pumpkin in weight.

36. It is worth noting that the size of the fetus directly depends on genetic characteristics. The average parameters of the fetus this week are: height - 48 cm, weight - 2.7 kg.

37. This week, the fetus is considered full-term. The average size of the crumbs can be about 3 kilograms and over 50 centimeters in height. The size of the baby resembles a medium-sized watermelon.

38. The prolapse of the abdomen is a harbinger of childbirth, and every mother at this time should already be ready for this. There are no changes in the development of the baby, and his weight and height at this time may remain unchanged.

39. It’s definitely impossible to call a child’s fetus anymore, since there is a full-fledged newborn in the tummy, which can be born at any moment. This week, the size of the baby can reach over 50 cm tall and 3.5 kg.

40. This is where the pregnancy comes to an end. As a rule, most children are born between 38 and 42 weeks, but still it is 40 weeks that is considered to be the gestational age.

How to be?

So, the answer to the question "Can ultrasound not show pregnancy" has been received. Now we know that such a situation is quite real. But what should a woman do in such a case? Firstturn it is important not to be nervous and concentrate. To finally deal with this issue, it is recommended to contact another clinic and undergo an ultrasound scan again. It is better to pass the survey on expert-class equipment, since such equipment has a high resolution. In addition, the examination should be accompanied by a blood test for hCG levels.

ultrasound picture


Practice shows that cases when a doctor cannot detect pregnancy using ultrasound are quite common. In such a situation, it is important for future parents to remain calm and make every effort so that diagnostic examination errors do not cost the baby's life.

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