28 to 40 weeks

3rd Trimester

Group B Strep - GBS

Group B Streptococus is a normal bacteria that 25% of women have in their vagina and/or rectum. It is not an infection but there is a chance that it could be passed on to the baby at the time of delivery. In rare cases, a baby could acquire a severe infection such as pneumonia or meningitis. As a result, we screen all women at 35-37 weeks gestation by first swabbing the vagina, and then the rectum. Women whose swabs are positive will receive antibiotics (Pencillin G unless you’re allergic to Penicillin) during labour.

Women who go into preterm labour (before 37 weeks), have had a bladder infection with GBS, or have had a previous baby affected with GBS will also be treated with antibiotics at the time of labour.

For more information please watch the video below about GBS. This video was developed by medical students at Queen's University in collaboration with faculty in the Department of Obstetrics and Gynecology.

Pertussis Vaccination

A pertussis vaccination booster is now available between 28 and 30 weeks gestation in every pregnancy. This is based on high quality evidence that the vaccine is safe in pregnancy, and will protect you and your baby from pertussis.

What is Pertussis?

Pertussis, or whooping cough, is a highly contagious infection that causes cold-like symptoms, followed by a serious and long-lasting cough. In Canada, most cases of pertussis occur in infants, and it causes more serious illness in infants than in adults. The severe cough can lead to vomiting, bruising in the eyes, a need to be admitted to hospital, and sometimes a need to help babies breathe with a ventilator. Rarely, babies have died from this infection.

Why Vaccinate during Pregnancy?

Babies are vaccinated for pertussis at 2, 4, 6 and 18 months old. Until the third dose of pertussis vaccine is received, babies are not completely protected. Pertussis is most common and most severe in infants, but protection for those early months can be transmitted to baby during pregnancy if a vaccine is given. Vaccinations given before pregnancy do not provide as much protection to baby.

After the vaccine, people often experience some pain at the vaccine site, and some redness is common too. Less often, people may experience a fever or chills, headache, tiredness, stomach upset, aches, or a rash. People may faint after receiving the vaccine. Rarely, people may have a severe allergic reaction.

Weekly Clinic Visits

In your third trimester, you will visit your health care provider every week. As with your previous clinic visits, your urine will be checked for protein, your blood pressure will be taken, and the size of your uterus will be measured. Your baby's heartbeat will be measured and you will discuss the baby's fetal movements. Your health care provider will also want to know about any changes or problems you may be experiencing, for example: bleeding, leaking of fluid from the vagina or uterine activity. As you near labour you may have questions about what to expect, or concerns over pain management, all of which can be discussed during these visits.