Anatomy scan pregnancy
Pregnancy: everything you need to know about obstetric ultrasound
Performed abdominally or endovaginally depending on the indications, obstetric ultrasound is used to check the development of the fetus, detect possible malformations and ensure that the pregnancy is progressing smoothly.
Painless and safe for both the fetus and the mother-to-be, ultrasound is a technique of choice to ensure that the pregnancy is progressing smoothly.
When to have an obstetric ultrasound?
The term obstetric ultrasound refers to ultrasound examinations performed during pregnancy. In general, health professionals recommend performing one ultrasound per trimester.
What are the 3 mandatory ultrasounds?
During pregnancy, three screening ultrasounds are strongly recommended:
- in the first trimester: between 11 and 14 weeks of amenorrhea;
- in the second trimester: between 20 and 25 weeks of amenorrhea;
- in the third trimester: between 30 and 35 weeks of amenorrhea.
Additional ultrasound scans may be performed depending on the patient's history, in the event of multiple pregnancies or clinical signs suggestive of a pathology: for example, an excess or a small amount of amniotic fluid, gestational diabetes, an infection such as rubella or toxoplasmosis, etc.
What are the different types of ultrasound scans for pregnancy?
The different types of obstetric ultrasound scans are:
- screening ultrasound scan;
- diagnostic ultrasound scan;
- and focused ultrasound scan.
Screening ultrasound scan
There are three types of prenatal screening ultrasound scans: they are performed in the first, second and third trimesters of pregnancy.
First trimester ultrasound: ensuring that the pregnancy is progressing normally
The first trimester ultrasound scan allows the future baby to be visualized in its entirety, to identify any malformations, to count the number of fetuses, to measure the crown-rump length (CRL) in order to precisely date the pregnancy and, above all, to assess the risk of genetic abnormality (screening for trisomy 21 ) thanks, in particular, to the measurement of nuchal translucency .
The so-called morphological ultrasound of the 2nd trimester: baby under the microscope!
In the second trimester, the so-called morphological ultrasound methodically studies the anatomy of the future baby. The examination lasts a little longer than the first, it allows to observe the limbs as well as the different organs of the fetus (brain, heart, kidneys, stomach, etc.), to ensure their good development and to detect possible malformations. This is also the time for parents who wish to discover the sex of their child !
3rd Trimester Ultrasound: Checking Fetal Growth
The third trimester ultrasound also includes a morphological study of the future baby and offers the practitioner the opportunity to estimate its weight. If it is too big, additional investigations will be carried out to ensure that the mother does not suffer from gestational diabetes. Finally, the practitioner will examine the structures surrounding the fetus – quantity of amniotic fluid, position of the placenta, umbilical cord – and check its presentation (breech, transverse).
Focused ultrasound
As its name suggests, focused ultrasound responds to a very specific indication. "We will focus on a very specific point". For example: monitoring the baby's growth, checking the amniotic fluid, checking the presentation of the fetus (breech) or analyzing the patient's cervix. "
Dating ultrasound
The dating ultrasound is part of the focused ultrasounds. "It is performed before the first trimester examination, only on indication" . For example: in case of doubt about the beginning of the pregnancy, irregular cycles, history of ectopic pregnancy , twins or unexplained bleeding."
The so-called diagnostic ultrasound
Diagnostic ultrasound is performed as a second option if the sonographer midwife or gynecologist discovers an unusual image or suspects an anomaly. " As soon as we have doubts about the screening, to confirm or rule out a possible pathology or discuss the course of action to take, we refer the patient to a referring physician to perform a diagnostic ultrasound " .
How is an obstetric ultrasound performed?
Obstetric ultrasound can be performed abdominally or transvaginally . " The two approaches complement each other ," says Pierre-Antoine Migeon. "Through transvaginal surgery, we can observe certain structures that we could not visualize through the abdomen and vice versa. We always start with the abdominal route and continue, if necessary, through the transvaginal route. " During the examination, the patient lies on her back and the sonographer moves the probe over her stomach to visualize the fetus. " No preparation is necessary, however, it is strongly recommended that expectant mothers do not apply moisturizer or oil to their stomach before the ultrasound so as not to harm the quality of the image". " There is also no need to come with a full bladder. However, it is advisable to drink enough water. Ultrasounds are much better when the tissues are well hydrated ." If the practitioner needs to go through the endovaginal route in order to examine certain structures that are more difficult to visualize through the abdomen, he will ask for your agreement and then insert an ultrasound probe into your vagina. Rest assured, the examination is not painful...
Obstetrical ultrasound versus gynecological or pelvic ultrasound
The term gynecological ultrasound refers to an ultrasound examination of the pelvic area. It can be performed by an obstetrician-gynecologist or a midwife in a specific context. For example: abnormal bleeding, pelvic pain or palpation of a mass during clinical examination. The examination consists of inserting a small probe into the vagina in order to visualize the uterus, cervix and ovaries. "We always start with the abdominal ultrasound and very often complete it with the endovaginal route after the patient's consent".
Gynecologist or midwife: what training is required to perform a fetal screening ultrasound?
Only doctors and midwives with a DIU in Gynecological and Obstetrical Ultrasound are authorized to perform the three pregnancy screening ultrasound examinations.