Back in 2008, a Reviews in Obstetrics and Gynecology article said:
“Most pregnant women likely do not get enough omega-3 fatty acids because the major dietary source, seafood, is restricted to two servings a week. For pregnant women to obtain adequate omega-3 fatty acids, a variety of sources should be consumed: vegetable oils, two low-mercury fish servings a week, and supplements (fish oil or algae-based docosahexaenoic acid).”
Although two of the three authors were employees of a supplement company, we shouldn’t dismiss what they say — a recent study at the University of Kansas seems to back it up. Pregnant women in this study were given either 600 milligrams of docosahexaenoic acid (usually called DHA for obvious reasons) or a placebo. The DHA group’s babies “were less likely to be very low birth weight and born before 34 weeks”, the findings say.
The study will continue for years to come, tracking the possible effects of DHA on the children’s development, but meanwhile, the researchers say, it “greatly strengthens the case” for pregnant women taking DHA. If you choose to do this, DHA is available over the counter, but you should talk to your doctor about it first, as with any complementary medicine.
It may be tempting to try to get your DHA simply by eating lots of fish. However, the Department of Health and Human Services recommends only eight to 12 ounces a week. Also, there are a few kinds of fish you should avoid during pregnancy: swordfish, tilefish, shark, and King mackerel (Atlantic and Pacific mackerel are fine). These are high in mercury. Albacore tuna is okay if you stick to one serving (about six ounces) a week. Though most other fish and shellfish are safe, you should eat them only if they’re cooked — smoked, cured, or made into jerky doesn’t count. The cooking is needed to kill bacteria. Try to eat a variety of fish — though that can be hard when you have cravings. If you don’ t like fish and don’t want to take supplements, there are still options like omega-3 eggs.
Womenshealth.gov has a “print and go” guide to safe seafood for pregnant women here.