Occasional hiccups caused by indigestion during pregnancy will not affect the health of the fetus. If the hiccups are persistent during pregnancy due to indigestion, or stress, or diaphragmatic spasms caused by eating spicy and irritating foods, they can affect the fetus during early or late pregnancy. In early pregnancy, frequent hiccups caused by diaphragmatic spasms can implicate the uterus in contractions and can easily cause a miscarriage. If diaphragmatic spasms occur in late pregnancy, with frequent hiccups that are relatively strong, they can also easily cause uterine contractions, leading to the possibility of preterm labor. You need to be treated promptly with medication to control the diaphragm spasms and relieve the hiccups. You also need to relax and not be overly stressed during this period.