All About The First Trimester Of Pregnancy

If the baby’s presence is not yet very visible from the outside, the first trimester of pregnancy is nevertheless rich in emotions and symptoms for the future mother. It is also a crucial trimester in the development of the future baby, which goes from the egg stage to that of an embryo, to finally become a fetus. What should the mother pay attention to during these first three months? What precautions should she take? What examinations should be done?

1st trimester of pregnancy: duration (number of weeks)


The first trimester of pregnancy lasts 13 weeks in total out of a total duration of 40 weeks on average, or about 284 days. However, there are two ways to count the advancement of a pregnancy: in the week of amenorrhea and in the week of pregnancy.

When does the 1st trimester start?

“The first trimester of pregnancy therefore begins on the first day of the last menstrual period if we are talking about a week of amenorrhea, or two weeks later if we are talking about a week of pregnancy.

When is the end of this term?

This first trimester is considered to end at 13 completed weeks when we speak of weeks of pregnancy, or at 15 completed weeks if we count in weeks of amenorrhea.

Egg, embryo, fetus: an extraordinary ascent!

Fatigue, nausea, constipation: the most common symptoms:


The first trimester is marked by many symptoms and inconveniences, under the influence of hormones, which can come to tarnish this beginning of pregnancy for the future mother.
“The most common symptoms are nausea, vomiting, disgust with smells, great fatigue and bouts of drowsiness, breast tenderness, and hormone-related constipation,” . This trimester can also be marked by frequent urges to urinate, following the change of axis of the uterus which compresses the bladder.In rare cases, the mother-to-be can suffer from hypersalivation, called hypersialorrhoea, which results in a production of saliva twice as important as in normal times, which can go up to 2 liters on day!

the strong fluctuations of hormones at the beginning of pregnancy often have an influence on the mood of the future mother, who can be subject to the emotional lift.

advices for the 1st trimester:


“The 1st trimester is very sensitive for the fetus, and we now know that certain factors will have a role in the future health of the child”. Advice related to food, lifestyle but also the use of certain cosmetic or body products, certain paints or household products, are useful for the future mother.

  • Limit processed foods and junk food,
  • favor as much as possible fresh, seasonal and pesticide-free foods,
  • preferably choose organic cosmetics;and avoid endocrine disruptors  such as phthalates, bisphenol A, parabens, etc.
  • “As throughout pregnancy, consumption of alcohol and tobacco should ideally be stopped from the start of pregnancy and until delivery,”

Sports: which ones are allowed? 

While it is important for the pregnant woman to maintain regular physical activity, care should however be taken to protect the fetus from possible shocks during the first months. Sports at risk of falling, such as horse riding, skiing, skating, cycling or climbing should be avoided. Be careful also with sports at risk of violent contact, such as handball, volleyball, basketball, and of course all combat sports

The recommended sports are walking, swimming, prenatal yoga, pilates, stretching and gentle gymnastics, while taking care not to put too much strain on the abdominal strap.

First trimester pregnancy exams++++


One of the first medical examinations proposed to the future mother in consultation is the realization of her blood group card – if she does not already have one. Whether her rhesus is positive or negative, a search for irregular agglutinin – RAI – is carried out in order to detect a possible rhesus incompatibility between the mother and her baby.

“Then, the mother-to-be must do a serology, for toxoplasmosis, rubella, syphilis and hepatitis B, HIV to which hepatitis C can be added

In the event of a history of diabetes in the family, of gestational diabetes during a previous pregnancy, of a BMI greater than 25 or of an age greater than 35 years: a fasting blood sugar level is prescribed for the pregnant woman, to screen for gestational diabetes.

“Depending on the history, a TSH assay is proposed to detect thyroid dysfunction. And for women prone to urinary tract infections, a urine culture should be performed”

Finally, screening for trisomy 21 can be done between the 11th and 13th week of amenorrhea. It is reimbursed by social security but is not compulsory.