Third trimester of pregnancy: medical checks

During the third trimester, the second-trimester exams are repeated: blood, urine and glucose tests, ferritin, toxoplasmosis antibodies, Combs test, and ultrasound.

However, others must also be done. We detail them to you.

In the last three months of pregnancy, you will have to repeat some tests that you have already been doing during pregnancy. To these are added those that detect the hepatitis B and HBSAG virus, hepatitis C, a vaginal and rectal culture, coagulation tests and cardiotocographic controls. Discover what controls each of them:

Hepatitis B and HBSAG virus

• This analysis is carried out again in the third trimester, between weeks 33 and 37, since the risk of transmission, very low in the first two quarters, increases up to 70% if hepatitis is presented in the final period of pregnancyIf the woman is positive (carrier without symptoms), the child will receive specific immunoglobulins as soon as she is born, to prevent her from contracting the disease. Then, you can feed your chest without problems.

Hepatitis C virus

• This is the specific analysis to check if the mother has antibodies against the hepatitis C virus. If positive, the virus genome (HCV RNA) should also be dosed, to see if, also to the antibodies, the virus is active. In this case, nothing changes concerning the mode of delivery, but it will be necessary to assess whether it is appropriate to suspend breastfeeding.

Vaginal and rectal culture

• It is usually done between weeks 35-37, to detect the presence of Streptococcus agalactiae (also known as group B streptococcus), a bacterium that can inhabit the vagina and rectum without the pregnant manifest any symptoms. If the result is positive, the future mother should be given antibiotics during childbirth, to prevent the infection from passing to the fetus during its passage through the birth canal.

Coagulation tests

• They are used to control that the blood of the future mother coagulates normally. This is an essential test since it allows predicting a possible risk of bleeding during childbirth and confirming whether epidural anesthesia can be used.

Cardiotocographic controls

• From week 37, cardiotocographic controls are usually prescribed (also known as fetal monitoring or “straps” ), which are used to control the fetal heart rate and the presence of uterine contractions. They are a great indicator of fetal well-being and offer the necessary data to determine if childbirth is more or less imminent.