The Second Trimester: 4 to 6 Months
By Month 4
By the end of the month, the fetus is eight to ten inches in length and weighs a half-pound or more. The mother will probably start to "show" now. The ears are functioning, and there is evidence that the fetus hears quite a bit.
By Month 5
Half the pregnancy has now passed, and the fetus is about 12 inches long. You should begin to feel movement. If a sound is especially loud or startling, the fetus may jump in reaction to it.
By Month 6
Oil and sweat glands are functioning. If the baby were born this month and given the proper care, he would survive.