The date of the second screening during pregnancy
About 25-30 years ago in our country there was no such thing as a comprehensive survey of pregnant women. In the absence of indications ultrasound was performed once for the entire period or not at all were appointed.
Modern medicine look differently at the management of pregnancy, and according to world standards expectant mothers are strongly recommended to pass the first and second screening. Ultrasound will help to evaluate fetal development.
The “Golden period”
The second trimester is called the “Golden period”, which lasts from 14-th to 27-th week. The level of hormones in the blood is gradually reduced, the body gets used to the changes. Morning sickness, nausea and excessive fatigue are losing ground, and pregnant women feel a surge of vitality.
Every two weeks the expectant mother visits a doctor, which monitors changes in blood pressure and body weight and also keeps the appearance of edema. Necessarily tests of blood and urine.
Separately, an obstetrician-gynecologist talks about the date of the second screening during pregnancy. Usually women are very nervous during these studies, but even if you fail, the probability of error is. Screening standards are also presented in our review.
The first screening
A two-tiered system of prenatal studies have appeared in Russia relatively recently. A comprehensive examination aimed at early detection of hereditary and congenital abnormalities in the fetus.
The first stage is conducted for a period of 10-14 weeks. Results 1 screening allow you to form a group risk for some congenital malformations and chromosomal abnormalities. Is carried out using ultrasound and blood test for PAPP-A and β-HCG. Additionally physician may prescribe a biopsy of the chorion in the following indications:
— increased nuchal translucency in the fetus (3 mm)
— women aged 35 years
— chromosomal abnormalities in the family.
The date of the second screening in pregnancy weeks 17-19. In the second trimester the expectant mother will also have diagnostic ultrasound and a blood test, often called a triple test.
The world health organization recommends a second screening to all pregnant and necessarily those who are at risk:
— age 35 years
— two miscarriages and more
— reception is contraindicated in pregnant drugs in the first trimester
— marriage between close relatives
— long-term threatened miscarriage
— pathology development of the fetus on the first ultrasound
Screening does not require special training. It is important to remember that after the twentieth week to investigate the blood on hormones it is impossible.
When carrying out diagnostic tests, experts estimate:
- The structure of the fetus and internal organs.
- The length of the cervix (36-40 mm).
- The quality and quantity of amniotic fluid (1-1,5 liters).
- The condition of the placenta (maturity 0).
As for the baby, then give an example of the period 18 weeks:
- Weight — 160-215 g.
- Growth of 20-22 cm
- The average size of the fetal head is 3.8-5.5 cm.
- The size of the cerebellum is 1.5-1.9 cm
- Diameter of the heart is 1.5-2 cm.
- The diameter of the humerus is 1.9-3.1 cm
- The diameter of the femur is 1.8-3.2 cm
- The diameter of the belly — 3,1-4,9 cm
The resulting norms ultrasound allow the doctor to make a conclusion about possible disabilities and to resolve the issue regarding additional research.
As we have said, the date of the second screening during pregnancy set in accordance with who recommendations. Thanks to the triple test specialists determine levels of three markers: HCG, free estriol and alpha-fetoprotein.
Blood tests are recommended during the seventeenth week of pregnancy. Screening, or rather the obtained values handles special program. The result is known only in two weeks.
The analysis requires some preparation. Doctors advise a day before a hike in the laboratory to eliminate from the diet citrus fruits, seafood, chocolate and cocoa, and fatty and fried foods. You need to eat at least 4-6 hours. It is permissible to drink 150 ml of plain water for four hours.
Let's take a closer look at the markers that appear in the triple test. Production of HCG is produced by the chorion of the fetus. Higher values may indicate multiple pregnancy, toxemia, or diabetes in a pregnant woman. In combination with low levels of two other hormones doctors suggest the risk of down syndrome.
Low HCG values allow to draw conclusions about ectopic or missed miscarriage, threatened abortion or fetal death, and chronic placental insufficiency. Increases the risk of Edwards syndrome.
AFP is a plasma protein, initially produced in the yolk SAC and then in the digestive tract and liver of the fetus. Low levels of AFP are talking about down's syndrome or illness, Edwards, low location of the placenta, diabetes the expectant mother.
Excessive levels of the hormone may signal risk of brain lesions, abnormalities of renal, duodenal atresia, neural tube defects and anterior abdominal wall. In addition, performance improvements are possible in the case of rhesus-conflict, water shortage, threat of abortion, and the death of a child.
Hormone synthesis occurs in the liver of the fetus and the placenta. During normal pregnancy levels of estriol increases steadily, which helps prepare mammary glands for lactation and improve blood flow in the uterine vessels. However, a sharp increase or decrease in its level can cause serious anxiety.
Reduced rates of estriol indicate the risk of miscarriage, anemia child, delayed physical development or intrauterine infection. There is also the likelihood of down syndrome, placental or adrenal insufficiency. Poor diet and antibiotics can also lead to a sharp decline in values.
High levels of estriol can be a sign of a multiple pregnancy or liver disease. In addition, experts with the drastic reduction of hormone predict premature birth.
So, time for a second screening during pregnancy and the results of the analyses allow us to draw preliminary conclusions regarding the presence or absence of genetic diseases.
However, there are factors that can influence the triple test. For example, IVF, multiple pregnancy, incorrect definition of term pregnancy, diabetes, and excess (or insufficient) weight women.
It is believed that if the figures for ultrasound and blood work are within normal limits, the baby is likely healthy. The reverse situation is the basis for assumption of risk of many pathologies, but on the basis of screening none of the Ob / GYN will not put the diagnosis. In this case the attending physician recommends further the conduct of other investigations (amniocentesis, expert ultrasound and cordocentesis), from which future parents have the right to refuse.
Since the beginning of the 14th until the end of the 27th week of the second trimester lasts. Screening raises concerns, a pregnant woman, because according to the research results it may be at risk. There is no greater grief than the disease of the child, even the unborn.
Diseases that doctors suggest for the results of the triple test:
- Down Syndrome. Immediately after conception, when the egg or sperm is an extra chromosome. Thus, in the fetus, instead of 46 chromosomes is formed 47 (extra — in the 21st pair). The likelihood of down syndrome is between 1-1. 5 %. To predict the disease in advance is impossible, but to a small extent on its appearance is affected by maternal age.
- Edwards Syndrome. Occurs similarly to down syndrome, but it turns out an extra chromosome in the 18th pair. Born in term babies resemble premature: weak, sickly and very small, with many defects of body parts and internal organs. Children with Edwards syndrome rarely live to their first birthday. The probability of disease is 1 case per 5000 newborns.
- A neural tube defect. On the 20th day of pregnancy, the neural tube is formed – first in the form of a plate. After a few days she should curl into a tube. This process occurs quite quickly, and fix the problem in the early stages is impossible. The neural tube may not fully close or to turn later, because of this, the child having hernia and spina bifida.
The date of the second screening during pregnancy is designed to detect these defects.