At week 18 the baby is now about 5 1/2 inches long and 5-6 ounces. They baby is moving a lot but the mother is just starting to feel it. The early sensation of fetal movement is called quickening. Quickening is often described as feeling flutters in the abdomen. Some times it can be hard to distinguish quickening from gas at first. If you feel a strange movement sensation that is different from your normal experience, this is the baby. Some people don’t experience quickening until about week 20 so don’t be worried of you don’t feel it yet. First time moms tend to feel the baby later than women who have been pregnant before.
18 weeks is when we typically order the anatomy screening ultrasound. This is a standard 2-D ultrasound but at 18 weeks it is very detailed. We can see all kinds of things about the baby’s structural development. There is a long checklist of items that we look for. This includes complex brain structures, facial features including ruling out cleft lip and palate, Heart structures, lungs, stomach, kidneys, bladder, arms, and legs to name a few. This is also the best time to check for gender, is the baby a boy or a girl. Ultrasounds are not perfect but they can be very good at finding abnormalities and normal structures.
People often ask if the ultrasound says it is boy or a girl is it correct. The answer is maybe. Ultrasounds are not ever 100% correct but the technology continues to improve. If the ultrasound technician says they are sure of the gender they are almost always right. If they say something like “I’m not 100% sure but I think it’s a …” I would save your receipts and refrain from painting the room gender specific.
There are endless wives-tales related to guessing gender. None of these actually work. The rate of the heart beat, how the baby is being carried in the stomach, the due date, how an object rotates over the pregnant belly, or any thing else you can imagine have all been used to predict the baby’s gender. None of them are better than 50% correct.
Second trimester screening is still available at week 18 if that is something you desire. It must be done before the start of the 20th week if you want the test.