It is unlikely that there is at least one woman who does not seek to determine the date of the upcoming birth and the estimated time of conception after learning about her pregnancy. And it is important for the obstetrician to know the exact period of pregnancy to assess and monitor the development and growth of the fetus and to timely carry out one or another corrective therapy. There are several known ways to find out the gestational age, but the most accurate of them is an ultrasound scan of the uterus and fetus.
Instructions
Step 1
Remember that ultrasound is safe for the fetus and has no limitations during pregnancy. In case of a favorable course of pregnancy, this type of perinatal diagnosis will be assigned to you three times.
Step 2
Please note that at different stages of pregnancy, the doctor has a different amount of information about the fetus, and the gestational age is set according to strictly defined criteria. Therefore, the so-called screening was developed and the terms were determined in which the ultrasound study carries more accurate information that is important for a given period of time. For example, at a gestational period of 2-3 weeks, only the ovum is visualized in the uterine cavity, roughly speaking, the doctor can give a conclusion whether there is a pregnancy or not. From the 4th week of gestation, an experienced ultrasound doctor can see the body of the embryo (on average, the size of the ovum will be 3-4 mm during this period). At 4-5 weeks, the heartbeats of the crumbs are recorded. Separate movements of the baby are visualized from the 7th week of intrauterine life.
Step 3
The head as an independent anatomical formation is determined from the 8th week, and the limbs from the 9th week of pregnancy. During this period, the doctor estimates the size of the average internal diameter of the ovum (SVD) and the coccygeal-parietal size of the embryo (CTE) and compares the data obtained with tabular or ultrasound scanners and determines the gestational age with an error of ± 6 days. At the end of the first trimester of development (11-12 weeks), individual brain structures of the unborn child can be scanned. It was at this time that ultrasound clarifies the gestational age, determines the number of fetuses, measures the thickness of the collar space and the nasal bone to exclude chromosomal defects.
Step 4
Be aware that in the future your baby on the display of the ultrasound machine will look more and more like a real person. Each time during the study, the doctor will measure the main indicators of the biophysical development of the fetus, namely: biparietal (between the parietal tubercles) and frontooccipital head sizes, chest circumference, abdominal circumference, nasal bone length, femur length. Certain tables and built-in programs for ultrasound machines have been developed, by which it is possible to determine the gestational age with an accuracy of ± 1 week.
