During pregnancy, the intake of fish oil is very important for fetal development and maternal health. Fish oil is rich in Omega-3 fatty acids, including EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid), which is very important for the development of fetal brain and eyes.

The best time to take fish oil is to start before pregnancy and continue to supplement it throughout pregnancy. This is because the development of fetal brain and eyes mainly occurs in the first three months and the last three months of pregnancy. Therefore, fish oil supplementation before pregnancy can ensure that you get enough Omega-3 fatty acids during critical periods.

However, if you are pregnant and haven't started to supplement fish oil, it is good to start to supplement it now. You can choose to take 1000-2000 mg of fish oil every day to ensure that you and your fetus get enough Omega-3 fatty acids. Be sure to consult a doctor or obstetrician to determine the specific dosage that suits you.

In addition, it is also important to choose high-quality fish oil products. Make sure to choose purified and tested products to avoid ingesting mercury and other harmful substances. It's best to choose products marked for pregnant women or suitable for pregnant women.

To sum up, the best time to take fish oil during pregnancy is to start before pregnancy and continue to supplement it throughout pregnancy. Taking 1000-2000 mg fish oil daily is a common recommended dose. Please consult your doctor for personalized advice and guidance.