Changes during pregnancy must be monitored through routine medical tests. We list them in this post, trimester by trimester.



Your pregnancy test has been positive and you are entering a unique stage. It's normal to be a bit stressed at first, thinking about all the months ahead, with possible discomfort and obligatory tests on your calendar. But take it easy. It's important to find out about the different stages of pregnancy and the tests you'll need to attend.


Which medical professional do I need for my pregnancy? The most common thing to do is to go to a family medicine doctor in the first instance. This is the person who will connect you with an obstetrician or a midwife. They will give you specific pre-birth training and will order many of the tests needed during pregnancy.


First trimester tests

Once you have confirmed you are expecting, you will need to make your first appointment with your doctor. This will take place approximately between week 6 and week 8, and at this meeting, you will calculate your due date based on the first day of your last menstrual period. 

During this initial consultation, the pregnant woman's medical history will be reviewed and a complete physical examination will be performed. If it has not been done recently, you will need a Pap smear. This painless, preventive test lasts only a few minutes and is important for diagnosing possible infections such as cervical cancer or the human papillomavirus.

The doctor will ask you about diseases and allergies, and begin to give you tips for a healthy lifestyle. You will be asked to undergo a blood test to rule out possible diseases and to evaluate the functioning of the body's organs.


The next follow-up test is the ultrasound scan at 12 weeks of pregnancy. This is an important test to determine whether it is a single or multiple gestation, and to rule out pre-eclampsia in the mother. The foetus will already be between 4 and 8 centimetres in size.

This test also measures nuchal translucency. This is an accumulation of fluid at the back of the neck of the foetus. There is a positive correlation between the size of the nuchal translucency and the likelihood of Down's syndrome. Thus, the results of this test are significant in understanding the risk of having this chromosomal abnormality. With this test it is still difficult to be sure of the sex of the baby.

 

Second trimester tests

The second ultrasound examination recommended during pregnancy is the morphological ultrasound. It is usually performed by an ultrasound scanner during the 20th week of gestation. This test, which does not cause any discomfort to the pregnant woman, lasts about 30 minutes and its main objective is to study in detail the development of the foetus and to detect possible malformations in its organs. It is during this ultrasound that the sex of the baby becomes clear.


The O'Sullivan test is usually performed between the 24th and 28th weeks of pregnancy. It is also known as the sugar test because blood glucose levels are tested in order to diagnose gestational diabetes early. A blood draw is performed before drinking glucose water, and another one hour after drinking glucose water.

 

Third trimester tests

It is around the 34th week that the third-trimester ultrasound takes place. The position of the foetus, the amniotic fluid of the placenta and the umbilical cord are analysed. All of this is important information to prepare for the birth.


Between the 36th and 38th week of pregnancy, a vaginal culture is also performed. This gynaecological examination, which is painless for the mother, consists of samples taken from the vaginal walls to examine the cells. Doctors look for a bacterium called streptococcus, which, if present, can cause complications for the baby. If the pregnant woman carries streptococcus, she will have to take an antibiotic to get rid of it. 


Is there still more to do? Yes, but don't worry, it is coming to an end. To ensure that the baby is completing its development correctly in the womb, there is a mandatory test for pregnant women: foetal monitoring. It is performed between 37 and 40 weeks of pregnancy and serves to check the baby's well-being, and heart rate and helps to better approximate the due date. It lasts approximately 30 minutes. It is usually performed externally, by placing sensors on the pregnant woman's abdomen. 


In addition to the ultrasound, vaginal culture and foetal monitoring, the third trimester also requires a blood and urine test to properly monitor the last phase. Let the specialists help you at all times and be serious about your testing schedule.

 

Less common tests


Amniocentesis is an invasive test that serves to make an exhaustive study of possible abnormalities in the baby's chromosomes. It is only done when there is already high risk of these alterations. It is usually done between 15 and 20 weeks of pregnancy and involves obtaining a sample of amniotic fluid and analysing its cells. An abdominal puncture is necessary to reach the gestational sac.


On the other hand, a corial biopsy is another invasive test that is performed between 10 and 14 weeks if there is suspicion of chromosomal abnormalities. The chorionic villi of the placenta are investigated from the cervix or from the abdominal wall.


Cordocentesis is a prenatal test that involves obtaining a sample of the baby's blood from the umbilical cord. It is an invasive test that requires a puncture and is performed from the 18th week of pregnancy onwards. It is used to detect foetal anaemia or low levels of platelets in the blood.