The "false labor" that can occur after the fourth month of the pregnancy is known as the Braxton hicks contraction. During these contractions, the uterus of the pregnant female tighten for a period of about 30 seconds to 60 seconds. Sometimes, these contractions can continue for 2 whole minutes. These contractions are also known as the 'practice contractions'.
Hence, the answer is 'Braxton hicks contractions'.