It is not uncommon for pregnant women to experience headaches during the second trimester, including around 16 weeks. Hormonal changes, increased blood volume, and changes in blood pressure can contribute to these headaches. However, if the headaches are severe or accompanied by other symptoms such as blurred vision or high blood pressure, it is important to consult a healthcare provider. To manage mild pregnancy headaches, try relaxation techniques, staying hydrated, getting enough rest, and using a cold compress on your forehead. If needed, your doctor may recommend safe pain relief options.