At week 5 of pregnancy, your embryo’s neural tube (which becomes the brain and spinal cord) is forming and a tiny heart tube is beginning to pulse. You don’t need any extra calories yet, but the nutrients you eat right now directly support this rapid development. Focusing on folate, choline, iron, and omega-3 fatty acids gives your body what it needs during one of the most critical windows of early pregnancy.
Why Week 5 Is a Nutritional Turning Point
The neural tube closes between days 21 and 28 after conception, which falls right around week 5. If it doesn’t close properly, serious birth defects of the spine or brain can result. This is the single biggest reason folate matters so much right now. By the end of week 5, your embryo’s heart tube will be pulsing about 110 times per minute, and the foundations of the central nervous system are being laid down. Every nutrient you take in is fueling extraordinarily fast cell division.
Folate: The Most Important Nutrient Right Now
The recommended intake of folate during pregnancy is 600 mcg per day, up from 400 mcg for non-pregnant women. Because folate is essential for DNA synthesis and rapid cell growth, getting enough of it during this window helps prevent neural tube defects like spina bifida. Clinical evidence shows that adequate folic acid intake around conception prevents a substantial proportion of these defects.
Your prenatal vitamin likely contains folic acid (the synthetic form), but food sources add up quickly. Dark leafy greens like spinach and kale, lentils, chickpeas, fortified cereals, asparagus, and avocado are all rich in folate. A single cup of cooked lentils provides roughly 360 mcg, so pairing food sources with your supplement is a reliable strategy.
Choline: The Nutrient Most Prenatals Miss
Choline works alongside folate to support your baby’s developing brain and eyes, yet most prenatal vitamins don’t contain it. Pregnant women need 450 mg per day, and over 90% of the U.S. population falls short of adequate choline intake even outside of pregnancy. That gap widens when requirements increase during pregnancy and breastfeeding.
Eggs are the simplest source. Two large eggs provide about 300 mg of choline. Beef liver is the most concentrated source, though it’s not for everyone. Other good options include chicken, salmon, soybeans, and shiitake mushrooms. Since you likely won’t get enough from a supplement alone, making choline-rich foods a regular part of your meals matters.
Omega-3s From Low-Mercury Seafood
DHA, an omega-3 fatty acid concentrated in fish, plays a significant role in fetal brain and eye development. Inadequate intake is linked to visual and cognitive deficits in infants. Current guidelines recommend pregnant women eat 8 to 12 ounces of low-mercury seafood per week, which provides roughly 250 mg of combined EPA and DHA daily. Nearly 95% of U.S. women of childbearing age don’t hit that target.
Good low-mercury choices include salmon, sardines, anchovies, herring, and trout. Shrimp and tilapia are also safe options, though they contain less DHA. Fish to avoid entirely during pregnancy include shark, swordfish, king mackerel, and tilefish, all of which accumulate high levels of mercury.
Iron: Steady Intake, Not Overloading
Your iron needs in the first trimester are relatively modest compared to later in pregnancy, rising from about 0.8 mg of absorbed iron per day now to 3 to 7.5 mg per day by the third trimester. That said, building healthy iron stores early helps your body handle the dramatic blood volume expansion ahead.
Lean red meat, poultry, beans, lentils, spinach, and fortified cereals are solid sources. Pairing plant-based iron with vitamin C (a squeeze of lemon on your lentils, bell peppers in a bean salad) improves absorption. There’s no benefit to taking high-dose iron supplements this early unless your provider identifies a deficiency. Excessive iron intake during pregnancy has been associated with adverse outcomes, including impaired blood volume expansion.
You Don’t Need Extra Calories Yet
One of the most common misconceptions about early pregnancy is that you’re “eating for two.” Energy requirements in the first trimester are the same as they were before pregnancy. The caloric increase doesn’t begin until the second trimester, when you’ll need an estimated 340 extra calories per day, rising to about 452 in the third trimester. For now, the focus is on nutrient density rather than quantity.
Managing Nausea Through Food Choices
Week 5 is often when morning sickness starts to ramp up, which can make healthy eating feel impossible. Eating small portions frequently throughout the day, rather than three large meals, helps keep nausea in check. Bland, starchy foods like crackers, toast, rice, and bananas tend to be easiest to tolerate. Keeping something in your stomach at all times (even a few crackers before getting out of bed) can prevent the empty-stomach nausea that hits hardest in the morning.
Vitamin B6 is commonly used to ease pregnancy nausea. A typical approach is 10 to 25 mg every 6 to 8 hours. Ginger, whether in tea, chews, or capsules, is another option with a long track record of helping. Cold foods are sometimes easier to tolerate than hot ones, since they have less aroma. If nausea is limiting your diet significantly, focus on whatever you can keep down and lean on your prenatal vitamin to cover nutritional gaps in the short term.
Hydration Matters More Than You Think
During pregnancy, the recommended fluid intake is 8 to 12 cups (64 to 96 ounces) of water per day. Water helps form amniotic fluid, circulates nutrients to the embryo, and supports digestion at a time when constipation often becomes an issue. If plain water triggers nausea, try adding a slice of lemon or cucumber, or sip on small amounts throughout the day rather than drinking large quantities at once. Herbal teas (check that they’re pregnancy-safe) and water-rich fruits like watermelon also count toward your daily intake.
Foods and Drinks to Avoid
Some foods carry risks that matter more during pregnancy because your immune system is slightly suppressed. The key ones to skip:
- High-mercury fish: shark, swordfish, king mackerel, and tilefish
- Unpasteurized soft cheeses: queso fresco, brie, camembert, and blue-veined cheese made from raw milk, which can harbor listeria
- Deli meats and unheated deli-sliced cheese: unless heated until steaming
- Raw or undercooked eggs, meat, and seafood: including runny yolks, rare steak, and sushi made with raw fish
- Unpasteurized juice and milk
Caffeine doesn’t need to be eliminated entirely, but keeping it under 200 mg per day is the standard guidance. That’s roughly one 12-ounce cup of brewed coffee. Tea, chocolate, and some sodas also contribute to your daily total, so it’s worth tracking if you consume multiple sources.
A Practical Day of Eating at Week 5
Putting this together doesn’t require a complicated meal plan. A realistic day might look like scrambled eggs on whole-grain toast for breakfast (folate, choline, iron), a handful of almonds as a mid-morning snack, a lentil soup with a side salad for lunch (folate, iron, fiber), an apple with peanut butter in the afternoon, and baked salmon with roasted sweet potatoes and broccoli for dinner (DHA, vitamin C, folate). If nausea makes any of that unappetizing, simplify. A banana, a few crackers, and your prenatal vitamin still cover essential ground on a tough day.