At 19 weeks pregnant, you're near the middle of your second trimester. The period of organ development, during which your baby-in-progress is most sensitive to toxins from the environment, has ended and the period of significant fetal growth has just begun. There are some foods that you should avoid during this time to help ensure your baby's health.
By far, the most sensitive period of pregnancy is near the beginning, when your baby's organs are developing. During this time, which is mostly completed by the end of the eighth week of pregnancy, environmental toxins and toxins in your diet can lead to significant birth defects. By the end of the first trimester -- and even more so by 19 weeks, the fetus is much less sensitive to toxins. Still, your baby is growing rapidly during this time, and its brain in particular is sensitive.
Risk of Infection
One potential problem of which you should be aware is that the food you eat can contain bacteria that might cross the placenta and damage your developing baby. Even foods that wouldn't ordinarily put a non-pregnant person at risk have the potential to cause serious bacterial infections in mid-pregnancy fetuses. Avoid soft cheeses made with unpasteurized milk and undercooked meats, as these can harbor dangerous bacteria, advises Dr. Miriam Stoppard in her book, "Conception, Pregnancy and Birth."
There also are toxins that can damage developing babies, even when they're well past the organ-development stage. Alcohol remains a risk throughout pregnancy, explain Drs. Michael Roizen and Mehmet Oz in their book, "You: Having A Baby." Similarly, some fish -- particularly swordfish, shark, and other large predator species -- can contain high levels of mercury. Mercury is a potent neurotoxin that can damage your baby's developing brain and nervous system.
With the exception of bacterial infections, which can kill second-trimester fetuses, most of the toxins to which you could expose your baby by eating certain foods won't result in fetal death, but they can result in damage to the developing brain and nervous system. Some toxins can also cause a reduction in fetal size or failure to achieve normal birth weight, which can affect the health of your baby and can lead to developmental delays even after birth, explain Drs. Roizen and Oz.
While most obstetricians advise women to avoid caffeine during the first trimester, many agree that it's OK to add a small amount of caffeine back into your diet by the middle of the second trimester. Drs. Roizen and Oz point out that the majority of caffeine-related effects noted in studies suggest that caffeine is most likely to cause miscarriage early in pregnancy in heavy caffeine users. If you miss your daily coffee, it's probably safe to consume a small amount -- no more than a cup a day -- starting at about 19 or 20 weeks into your pregnancy.