According to Babycenter: The network of nerves in your baby's ears is better developed and more sensitive than before. He may now be able to hear both your voice and your partner's as you chat with each other. He's inhaling and exhaling small amounts of amniotic fluid, which is essential for the development of his lungs. These so-called breathing movements are also good practice for when he's born and takes that first gulp of air. And he's continuing to put on baby fat. He now weighs about a pound and two-thirds and measures 14 inches (an English hothouse cucumber) from head to heel. If you're having a boy, his testicles are beginning to descend into his scrotum — a trip that will take about two to three days.
Are you rushing around trying to get to childbirth classes and prepare your baby's room while still taking care of all your other daily tasks? Make sure that you also continue to eat well and get plenty of rest. Around this time, your blood pressure may be increasing slightly, although it's probably still lower than it was before you got pregnant. (Typically, blood pressure falls toward the end of the first trimester, and it tends to reach a low at about 22 to 24 weeks.)
If your lower back seems a little achy lately, you can thank both your growing uterus — which shifts your center of gravity, stretches out and weakens your abdominal muscles, and may be pressing on a nerve — as well as hormonal changes that loosen your joints and ligaments. Plus, the extra weight you're carrying means more work for your muscles and increased stress on your joints, which is why you may feel worse at the end of the day. Walking, standing, or sitting for long periods, as well as bending and lifting can all put a strain on your back. A warm bath or hot compress might bring relief. (Some women, though, find cool compresses more comforting.) Try to maintain good posture during the day, avoid activities that require bending and twisting at the same time, take frequent breaks when sitting or standing, and sleep on your side with one or both knees bent with a pillow between your legs, using another pillow (or wedge) to support your abdomen.
Turns out there are very few pictures of Hothouse Cucumbers on the internet. Probably because if you don't know what they are live in a cave and therefore do not use internet.