Eating watermelon in moderation during late pregnancy generally has no effect on the fetus. However, watermelon contains high sugar content, if pregnant women have gestational diabetes mellitus, it may affect the blood sugar of pregnant women, which in turn affects the development of the fetus. Watermelon is rich in glucose, vitamins and other nutrients, pregnant women eating watermelon can provide nutrition for themselves and the fetus, and will not affect the development of the fetus, pregnant women can eat watermelon properly. However, it should be noted that watermelon should not be eaten frozen, so as not to affect the gastrointestinal function of pregnant women, abdominal pain, diarrhea and other discomforts. Pregnant women with gestational diabetes should also not eat watermelon, which is rich in glucose and will affect the blood sugar of pregnant women. Pregnant women with gestational diabetes need to strictly control their blood sugar so as not to affect fetal development.