Don't let coffee "bitter" the fetus during pregnancy.

Caffeine's delicious flavor has become a leisure drink for both young and old, but Danish researchers wrote in the British Medical Journal that pregnant women who drank eight or more cups of coffee a day had more than twice the risk of stillbirth than those who did not drink coffee, according to the China Daily website.

The researchers conducted a retrospective survey of women admitted to hospital during pregnancy in the seven years since 1989, including their coffee consumption, smoking and alcohol habits during pregnancy. The researchers found that pregnant women who drank eight or more cups of coffee a day during pregnancy had a significantly higher risk of stillbirth than women who did not drink coffee, and the risk did not decrease significantly after excluding factors such as smoking and drinking.

The researchers explained that caffeine in coffee can cause an increase in adrenaline secretion in pregnant women, causing vasoconstriction and causing hypoxia in the fetus; another possible explanation is that caffeine enters the fetus through the placenta, directly affecting the fetus's cardiovascular system, or figuratively speaking, the fetus drinks a lot of coffee. However, because the fetal heart is very fragile, coffee stimulation caused by tachycardia or arrhythmia will often make the fetus "overwhelmed" and die.