Ultrasound at week 12: holding norms


Today, ultrasound is the most informative method to assess the level of fetal development. It 12 week it is already possible to assess the degree of development of the internal organs and to identify possible malformations. In addition, a 12 week to have first prenatal first trimester screening.

Foetal development by the end of the third month

12 week is the last one in the first trimester of pregnancy, and it is at this period it is possible to objectively see the characteristics of the development of the fetus. On the third month the baby is already well developed, the principal organs are practically formed, actively differenziata small structure.

Ultrasound in the third month doing two ways – transvaginal and transabdominal probe.

A study of the transvaginal transducer at this gestation are doing much less and often in the presence of certain indications. These include:

  • Low attachment of the chorion or placenta.
  • Women diagnosed with isthmic-cervical insufficiency, and the need to determine the level of cervical dilatation.
  • The presence in the patient of fibroids complicating transabdominal diagnosis.
  • Uninformative transabdominal method in cases where the patient has significantly developed subcutaneous fat, or the location of the fetus does not allow to make the necessary measurements.

When conducting ultrasound through the abdomen of the woman to prepare to drink about half a liter of liquid. This is because a filled bladder passes the ultrasonic beams and significantly improves the visualization of the uterus and fetus.

The decoding results of the survey

During the ultrasound the doctor assesses the level of development of the fetus, its gestational age, the condition of the uterus and ovaries, take all necessary measurements. Screening results shall be recorded in the conclusion. All actions of the doctor are strictly stipulated in the examination report. The main points of the Protocol:

  • First check the number of embryos.
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It was after 12 weeks it is possible to differentiate twins from triplets. If there are two fruits, you need to figure out what the twins are identical (twins) or dizygotic (twins).

  • Evaluation of the presentation of the fetus.

The doctor checks what part of the body the fruit is to the exit from the uterus. At 12 weeks probably any position – pelvic, the head or transverse or oblique. 30 weeks this option can be repeatedly changing.

  • Fetometry of the fetus.

The specialist performs the necessary measurements is the main goal of ultrasound at week 12, these results are determined by the deviations in the development of the baby. Measure:

  1. Biparietal head size – distance from the edges of the parietal bones. Normal is equal to 20-21 mm.
  2. Growth – in the third month on average, 82 mm. in boys this figure is often more than girls.
  3. Fetal weight – not less than 17 grams. Boys are often bigger than girls.
  4. Thigh length – 8-9 mm — the value at week 12 of pregnancy is moderate.
  5. Measurements of nuchal translucency – from 0.7 to 2.5 mm, mean 1.7 mm. the Definition of this parameter is very important for the diagnosis of genetic diseases – down syndrome.
  6. The nasal bone is 2-4 mm, with an average of 3.1. Another important parameter screening of the third month for the diagnosis of hereditary diseases. Boys and girls of this parameter are the same.
  7. Kopcik-parietal size 40-70 mm.
  8. Head circumference – 55-85 mm, an average of 70, the boys can be a little more.
  9. Chest circumference – 53-73 mm, average size 63.
  10. Length of the humerus is 7-11 mm in this month, averaging 9.
  • See the state of the umbilical cord.
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To exclude or confirm the entanglement of the umbilical cord, its multiplicity.

  • Heart rate.

Normal 150-175 beats per minute.

  • The condition of the amniotic fluid.

The specialist checks the number and transparency, reveals the blurred – such as waters says of a possible accession of intrauterine infection.

In the case when there is a decrease or increase any parameter, the doctors look at the proportion of other sizes in General, perhaps the fetus is larger or Vice versa small. If most of the values are much below normal, the doctor puts intrauterine development. One should not exclude the possibility of incorrect setting of pregnancy, a woman may make a mess of the date of the last menstruation. Also taken into account the Constitution of the mother and the father if the couple are both small built, the child is likely to be the same as boys in most cases inherit his father’s physique.

Safety of the method

Many women often say to my doctors «I’m Afraid to do an ultrasound, then it will harm the baby.» In fact, nothing dangerous, no research and don’t be afraid, the benefits of the results obtained greatly exceeds the theoretical possible harm. However, this does not mean that you can do an ultrasound at any possible occasion. Be sure to listen to the advice of his physician.

First trimester screening

In addition to the ultrasound at week 12 make the first prenatal screening. This study allows high accuracy to determine the likelihood of the fetus has different genetic diseases. In the screening of the third month included an analysis of venous blood.

The survey is recommended for all pregnant women, but in some cases, screening is necessary. This group includes:

  1. Women married to a close relative.
  2. Missed abortion, stillbirth or more than 2 abortions/premature birth in anamnesis.
  3. Viral infection during pregnancy.
  4. There are relatives, patients with patau syndrome or down’s syndrome.
  5. The couple already have children with genetic diseases.
  6. It’s forbidden in pregnancy drugs.
  7. Women aged more than 35 years.
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In the blood analysis includes a screening level determination of two hormones – HCG and PAPP-A (protein A, pregnancy associated):

  • The decrease in the level of HCG indicates a possible pathology of the placenta, or questioning Kindom Edwards. An increase in the level of HCG in the results of the screening test indicates an increased risk of down syndrome.
  • The decrease in the level of PAPP – a disturbing symptom that indicates a high risk of developing down syndrome, Edwards, and about the risk of abortion. Do not be afraid of increasing hormone levels – this only shows that the fetus may be large.

After receiving the results of ultrasound and blood screening, the doctor summarizes the data obtained, and on this basis concludes that the fetus and the level of development, respectively the stages of pregnancy. All the received data are entered in conclusion.

Mandatory ultrasound of 12 week of pregnancy significantly increases the probability of having a healthy baby, because a correct diagnosis in the early stages of pregnancy allows time to take all the necessary measures.