is a primitive form of immunity called toll-like receptors (TLRs). They work a bit like an alarm system, recognizing cells as evil or friendly and then alerting other immune cells (namely, T cells and B cells, also known as T lymphocytes and B lymphocytes) to do the dirty work. By the end of the first trimester, B lymphocytes are produced in the fetal liver, while T lymphocytes develop in the thymus—a gland in the chest that is large in babies but small in adults.* By this time, the fetus is much better able to withstand sophisticated invaders and potential threats than it was when just the TLRs were in place. Along with the timing of the fetus’s major organ development, the fact that the fetal immune system isn’t fully functional until the second trimester is why you have to be especially careful about exposure to toxins and infectious agents during your first trimester.
T cells work by looking for bad guys in the body and creating memories of any potential invaders they encounter, such as bacteria, viruses, or parasites. It’s a biological Most Wanted List of sorts. The T cells act as the captains and generals of the fetal immune-system army, deciding how many immune cells will respond to potential threats and ensuring that the body doesn’t over- or underrespond. B cells serve as the privates, waiting for a signal to tell them whether the invader is a good guy or a bad guy. Once they know it’s a bad guy, they start making antibodies and blasting away.
Recent research shows that the fetus’s cells and the mother’s immune system join forces to fight infections and other common enemies. When the fetus’s cells call for help, the mother’s system responds to the TLR alarm and sends reinforcements throughout pregnancy.†
So, in many ways, the placenta is the unsung hero of pregnancy, dutifully providing your baby with nutrients and immunity. That’s not to say it couldn’t benefit from a bit of attention. If you do right by your placenta, it’ll do right by your child—with potentially lifelong effects.
Drat, Cat
Of course, your partner is already doing everything he can to help you during your pregnancy (including making you scrambled egg tacos at four in the morning). Add this one to the list. If you have a cat, put your partner in charge of taking out the kitty litter. The litter of some cats includes a parasite that can lead to toxoplasmosis, a condition that can restrict the growth of the fetus. Your cat is the primary host of the toxo parasite and can shed egg cysts in its feces that survive for a long time. But don’t worry: It’s still okay to pet Mr. Moo-Moo. Just be sure to wash your hands very well in running water after doing so. The parasite can also infect raw food (via a fly that flits from the litter box to your hamburger meat). So wash and cook your food to a temperature of 145 degrees for beef, lamb, steak, and veal roasts; 160 degrees for pork, ground meat, and wild game; and 180 degrees for whole poultry. And clean all surfaces that have touched raw meat.
Toxoplasmosis causes flulike symptoms, with muscle aches, brain fog, and swollen glands. Toxo is a threat to your baby only if you’re infected for the first time during pregnancy. (You may have immunity to it if you’ve already been exposed.) Your provider can perform a simple blood test to check whether or not you have antibodies. If not, try to avoid exposure to litter while pregnant. If you don’t have an alternative to changing the litter while pregnant, either wear gloves or wash your hands thoroughly afterward. Toxoplasmosis egg cysts can survive for up to a year in soil, so wear gloves when gardening as well.
Figure 2.3 Good Soldiers A fetus’s early immunity comes in the form of T cells and the primitive toll-like receptors, which work together to identify and fight off potential invaders. The immunity process in pregnancy is one of a kind, as the mom’s body must help protect what it might initially see as a potential invader.
* The placenta is named after the Greek word plakos, which means “flat cake,” because of its appearance.
* After all, ain’t enough room for a restroom down there.
† Some bigger substances, like immunoglobulins, can pass through by folding themselves into smaller
* Morning sickness may seem like a form of rebellion, but it’s really more of an ally, as we’ll explain in a few pages.
* This gland shrinks dramatically with age; in fact extracts of thymus are injected by suspect antiaging docs, supposedly to bring vitality to aging clients.
† TLRs are the oldest immune system and the dominant system in ancient species, like the shark.
There aren’t a whole lot of products out there that really tout their placental benefits. It’s not like yogurt containers, cereal boxes, or jugs of OJ contain such marketing gems as “100% Placentally Fortified!” or “Boost Your Blastocyst!” So you may be unaware that there are indeed things that you can do to improve placental function. Above all, you want to maintain good arterial health yourself—namely, by doing many of the things we list below. And by avoiding exposing yourself to toxic substances, you won’t risk transmitting them through the placenta to your baby.
Follow the Basics. Several things have been shown to contribute to optimal placental function. Not surprisingly, they’re also good for a healthy pregnancy in many other ways. They are:
• Don’t diet during pregnancy.
• Get your extra calories with extra protein.
• Exercise wisely.
• Don’t smoke.
• Avoid exposure to high altitudes.
• Avoid exposure to potentially toxic chemicals such as pesticides.
Follow These Med Rules. On page 342, you’ll see our guidelines for specific medications that have been deemed safe or unsafe to take during pregnancy (most are generally okay). While we recommend using that list as a guide, we also believe that you should follow these basic principles:
• Don’t self-prescribe meds. Any pill you want to pop, run it by your obstetrician or midwife first.
• Don’t stop any medications you’re currently taking. The issue of medicine is often a risk-versus-benefit decision. If you’re at high risk of developing a complication by not taking your medication, you may very well be putting your baby in harm’s way by stopping.
• Don’t rely on the average internet site. It’s easy to get caught up in message boards and the thousands of health sites out there. When it comes to medical info, you need to make sure the source is reliable and respectable. Three sites we recommend for cutting-edge updates: www.motherisk.org, www.realage.com, and www.drugsafetysite.org.
• While your doc will advise you on medication doses, you should know that you may need a higher dose as your pregnancy progresses, because the rate that your body breaks down drugs while pregnant differs from the nonpregnant state.
Note: If you’re interested in complementary medicine, choose a provider who shares your perspective