It is difficult to study the true effect of coffee on fetal development. The current conclusion on this issue can only rely on observation and theoretical analysis. Based on the available data, two conclusions are relatively clear: first, it is not recommended for pregnant women to drink coffee; second, under the usual amount of drinking (1,2 cups per day), there is no evidence that coffee has a substantial effect on fetal development harm.

　　1. Caffeine

　　Caffeine is the main functional component of coffee, generally insoluble in cold water, but easily soluble in hot water. Caffeine does not accumulate in the body and is excreted with urine after a few hours. The impact on the body is transient, so the action time of a cup of coffee is usually relatively short, and many people have to drink and drink again. In addition to coffee, tea, cocoa, chocolate, cola drinks, and some functional drinks also contain small amounts of caffeine. The benefits and possible harms of drinking coffee are closely related to caffeine, which is the focus of our discussion. In addition to caffeine, trans-fatty acids and excess sugar in coffee mates or non-dairy creamers may also cause health problems.

　　The most obvious effect of caffeine is to refresh and energize people. This refreshing effect is not only related to brain excitement, but also to psychological dependence, and has obvious characteristics that vary from person to person. Some people are more sensitive to caffeine, the refreshing effect is particularly obvious, and may even cause insomnia or difficulty falling asleep. Some people, especially those who often drink coffee, are less sensitive and sometimes do not even feel refreshed. Drinking coffee for a long time is really refreshing, or is it just a habitual psychological dependence? Sometimes it is difficult to identify.

　　The excitatory effect of caffeine on breastfeeding babies is easy to observe. The mother drinking coffee will make the baby hyperactive and sleep less. Pregnant women drinking coffee often also increase the frequency and amplitude of fetal movement. The actual harm of these effects is still unknown. However, in theory, caffeine can pass through the placenta and have the effect of constricting blood vessels, which can significantly reduce the blood flow of the placental chorion and thus affect the fetal development. Studies have found that caffeine can reduce fetal birth weight, and the more caffeine intake, the more grams of fetal birth weight will be reduced. To this end, the US Food and Drug Administration (FDA) has issued a statement recommending that women who are or may be pregnant reduce caffeine intake.

　　 The FDA’s recommendation is to "reduce" caffeine intake rather than "ban" it. How much reduction is more appropriate? This is obviously a difficult question to answer accurately. For non-pregnant women, the general recommendation is not to consume more than 200 mg of caffeine per day, that is, no more than 3 cups of coffee per day (instantly packed coffee). The caffeine content of different types of coffee varies greatly. A cup of coffee in a coffee shop (250-280 ml) contains 150 to 200 mg of caffeine.

　　 For women who are pregnant or may become pregnant, do not exceed 1 cup (instantly packed coffee) per day. When it is found that the fetus has an excitement reaction (fetal movement is significantly increased), it is necessary to stop drinking coffee. Even if the fetus does not show obvious excitement, it is necessary to monitor the fetal growth rate. If the fetus is found to be slower (less than gestational week), it should stop drinking coffee.

　　These recommendations are based on the effect of caffeine on the fetus, so those low-caffeinated coffee (1 cup of coffee contains only 3 mg of caffeine, which is roughly equivalent to 20% of ordinary coffee A) Not within this limit. In other words, you can drink a few cups of low-caffeine coffee. Before the coffee beans are sent to the roaster, they are processed to separate most of the caffeine, so that the caffeine in the coffee is only about 5% of the "residual", which is low caffeine coffee. However, regardless of the level of caffeine, drinking coffee will bring some other health problems that deserve attention.

　　2. Trans fatty acids

　　In addition to caffeine, the creamer in coffee mates or instant coffee may also cause adverse effects. The ingredients of the non-dairy creamer (coffee companion) are relatively complex, mainly including glucose syrup, hydrogenated vegetable oil and various food additives, such as emulsifiers, water retention agents, antagonists, etc. For the time being, all kinds of complex and diverse food additives are ignored. The "trans fatty acids" contained in hydrogenated vegetable oils are potentially harmful to the fetus.

　　 "trans" is relative to "cis". The so-called trans-fatty acids refer to fatty acids with hydrogen (H) on both sides of the double bond according to the molecular space structure. The opposite is "cis-fatty acid", which is a fatty acid with hydrogen (H) on the same side of the double bond. In natural foods, most fatty acids are cis-fatty acids, and trans-fatty acids are few and far between. The main source of trans fatty acids is a special class of processed oils and fats-hydrogenated vegetable oils.

　　 The so-called hydrogenation refers to a special oil and fat processing technology. Hydrogenated vegetable oil, in short, is to convert unsaturated fatty acids in vegetable oils such as palm oil and rapeseed oil into saturated fatty acids by adding hydrogen to obtain many very good properties, such as lubricating taste, not easy to oxidize, etc. It is very important to improve the taste of coffee. But at the same time, hydrogenated vegetable oils often contain a certain amount of by-products-trans fatty acids.

　　 Trans fatty acids have been proven to be harmful to health. At present, it is very clear that the harm is caused by dyslipidemia, which increases the risk of coronary heart disease. Other studies have found that trans fatty acids can be transported to the fetus and infants through the placenta and breast milk, and affect their growth and development. The World Health Organization (WHO) recommends limiting the intake of trans fatty acids, no more than daily 1% total energy (about 2 grams). my country''s national standards for infant formula (GB10765, GB10767, GB10770) also prohibit the use of hydrogenated vegetable oils.

　　However, coffee mates or non-dairy creamers are not the only source of trans fatty acids. Bread, biscuits, instant noodles, egg yolk pie, pastries, fritters, french fries, potato chips, various crisps, puffed snacks, salad dressings, milk tea, etc. are commonly used hydrogenated vegetable oil and contain trans fatty acids. Moreover, compared with these processed foods, the content of trans fatty acids in the non-dairy creamer is actually lower. Therefore, as far as trans fatty acids are concerned, it is not enough, or even critical, for pregnant women to control coffee consumption.

　　Pregnant women should keep less coffee companions when drinking coffee, and choose less instant coffee with non-dairy creamer. You can directly add hot whole milk to the coffee, which not only tastes the same as fragrant, but also has more nutritional value high.

　　3. Others

　　coffee will interfere with the absorption of calcium, iron, zinc and other minerals in the intestine, reducing its absorption rate. Therefore, when drinking coffee, try not to be mixed with food.

　　 Coffee is bad for patients with gastritis and ulcers. Because coffee can promote gastric juice secretion and increase gastric acid, pregnant women with poor stomach and intestines should pay more attention when drinking coffee and do not drink coffee on an empty stomach.

　　 Coffee will cause calcium loss. Some studies say that caffeine increases the calcium excreted in the urine, thereby increasing the risk of osteoporosis. This is obviously not good news for pregnant women who need a lot of calcium. So women who drink coffee regularly should pay attention to calcium supplementation.

　　All in all, if measured comprehensively, coffee will do more harm than good to pregnant women. Coffee hardly contains any important nutrients or is very low in content. This is really not a good thing for pregnant women who need a lot of nutrients. Therefore, it is best for pregnant women not to drink coffee, and must be limited to drink as much as possible. Of course, this suggestion does not mean that drinking coffee will cause great harm to the fetus. This objective attitude also applies to other foods containing caffeine, such as tea, cocoa, chocolate, cola drinks, etc.