4 Weeks Pregnant

Most of your vitamin D supply comes from the sun or fortified milk. If you don't drink the white stuff, you'll need to find your D from other sources.

That's because vitamin D is essential for maintaining healthy teeth and bones, and helps your body absorb calcium (and you already know why you need to absorb plenty of that).

You can find vitamin D in many prenatal vitamins as well as from fortified milk, fortified orange juice and egg yolks. Talk to your doctor about how much you need (600 IU is the standard recommendation among the expectant set, but some may need 1,000 IU or more).

Think you need a Ph.D. in quantum physics to figure out your due date? Doing the math is actually a lot easier than you think — even if you slept through high school algebra. Your estimated due date is 40 weeks from the first day of your last period.

Here's the slightly confusing part: If you do give birth on that day, your baby will have clocked in only 38 weeks in utero, not 40. That's because the pregnancy countdown begins two weeks before your baby is even conceived — making you about four weeks pregnant before you see a positive pregnancy test.

Regardless, you shouldn't plan your schedule around your estimated due date. After all, it is just an estimate. Most babies are born between 38 and 42 weeks, and babies of first-time moms are more likely to arrive on the later side. Only a handful of babies actually make their debuts right on schedule.

Learn more about how to calculate your due date.

Your baby needs some fat — especially essential fats like omega-3 fatty acids. DHA, one of those omega-3s, is a major component of the human brain and retina and it’s important for your baby's developing brain and eyes.

You can get DHA from pregnancy-safe fish such as trout and wild salmon and from DHA-fortified eggs. If you can't stomach fish, you can also find DHA in prenatal vitamins and supplements, including a vegetarian DHA made from flaxseed.

You may not smoke, but if those around you do, there could still be risks to baby. Recent research has found that exposure to secondhand smoke may increase your risk of miscarriage, low birth weight, ectopic pregnancy and other complications. So try to steer clear as much as possible.

Often, what starts out as a comfort food (meaning one of the few things you can stomach) later becomes associated with nausea — and actually starts to trigger another round of the queasies because you’ve eaten so much of it.

If you’re so sick of saltine crackers that they’re actually beginning to make you sick, for example, switch to another comforting carb instead.

If you haven't already, now's the time to make your first doctor's appointment! Some OB/GYNs ask that you wait until you’re at least 6 to 8 weeks pregnant before a visit, but since early prenatal care is so important, it's best to get something on the calendar as soon as you have a positive pregnancy test.

Make sure to research the kind of doctor or midwife you really want first.

You may be eating for two (or, more accurately, one and a fraction) these days, but your menu just got a whole lot smaller. The reason for cutting out sushi, runny eggs and raw cookie dough batter? To safeguard against foodborne illnesses like listeria and salmonella.

Some of the most common food poisoning culprits are undercooked proteins like poultry, eggs, meat or fish, and raw dairy or juices.

On the off chance that you are sickened by food poisoning from salmonella, the bug will likely have to run its (unpleasant) course. But don’t worry, because it's unlikely that your baby will be in any danger.