What to expect in the third trimester?
Lots of growing! -- baby gains about half of their birth weight in this last trimester! You will typically gain between 1/2 to 1lb a week
Some symptoms from first trimester return! -- Nausea and the need to pee, which were caused by hormones in the 1st trimester can return due to the growing fetus putting increasing pressure on the digestive tract and bladder.
Fatigue also frequently returns.
New or increasing symptoms for the third trimester! -- There are lots of symptoms that can begin or exacerbate due to the increasing size and weight of baby, including shortness of breath, swelling, aches and pains in the hips, back and pelvic area, hemorrhoids, braxton hicks.
Increasing office visits with your provider -- At most traditional OB's, you will move from seeing your provider every 4 weeks, to every 2 and increasing to 1 week or less by the end. They will typically test for Group B Strep in the upcoming weeks and possibly some other labs. Towards the last few weeks your provider may offer to check your cervix for dilation and effacement, but it is YOUR choice to do this.
Some preparations for the third trimester:
Rest. Rest. Rest. Get the rest you can, while you can
Prepare your nursery
Make sure you have everything you need for baby, especially a car seat!
Attend any birthing, postpartum or breastfeeding classes
Pick a pediatrician
Pack your hospital bag
Iron out your birth plan, if using one and discuss it with your provider and any birthing support people
Tour your local birthing facility (if it is an option right now)
Make a family plan for visitors and dividing responsibilities after baby arrives