At 17 weeks the baby is about 5 inches long and about 4-5 ounces. When discussing length it is traditional to talk about “crown-rump” length. This is the distance between the sacrum (bottom) and the top of the head. The baby is curled into the fetal position so this is the length we can measure on ultrasound.
17 week babies are swallowing amniotic fluid. This serves several important functions. Swallowing the amniotic fluid helps exercise the muscles responsible for swallowing. This allows the swallowing abilities to be available when the baby is born. It also helps stimulate the gastrointestinal tract helping it to develop. The swallowed amniotic fluid gets absorbed and then processed through the baby’s kidneys to be excreted as urine. Amniotic fluid is made from the baby’s urine. It may sound strange but we all started life living in and drinking amniotic fluid, our own urine.
It is still possible to get second trimester screening at 17 weeks. The second trimester blood test can be done as late as 19 weeks and 6 days. Amniocenteses can be safely done at 17 weeks as well. These tests are optional and not everyone will want to do them.
The second trimester is a time when most women feel their best. Headaches are a common problem that tends to be worse in the second trimester especially in women that suffer from migraines when not pregnant. Tylenol is the first line therapy for headaches in pregnancy. Caffeine can help with headaches as well and is safe in pregnancy. I often recommend Tylenol and a cup of coffee or some soda for headaches. If this is not effective, Fioricet can be prescribed. Fioricet is a prescription headache medication that is safe for pregnancy. It contains Tylenol, caffeine, and a barbiturate. Talk to your doctor if you are experiencing bad headaches that are not relieved with Tylenol and caffeine.
Some women are starting to feel little flutters called quickening at 17 weeks. This is the baby moving. Women that have had babies before tend to feel this earlier then first time moms. If you do not feel it yet, don’t be worried. Many women do not feel movement until around week 20. But if you feel a strange sensation in your abdomen that is new, it is probably the baby.