Chocolate cysts usually do not grow any larger during pregnancy at 16 weeks. Chocolate cysts are a symptom of endometriosis and usually increase in size with the menstrual cycle, but they usually do not grow after pregnancy because menstruation does not recur. However, regular ultrasound checkups are needed to monitor the cysts. If the cysts continue to grow, surgery may be needed to remove them. Chocolate cysts usually do not grow after pregnancy. Chocolate cysts are caused by the lining of the uterus growing outside of the uterus. The lining of the uterus grows outside of the uterus and sheds blood regularly with the menstrual cycle, whereas a woman who is pregnant will not have a menstrual period during the entire pregnancy, so the lining of the uterus does not shed blood cyclically and will not grow in size. It is important to note that if a chocolate cyst grows in size, it should be treated promptly by a doctor.