Consider adding in Eggs into the diet for their Choline content. Choline has been shown to benefit unborn children through maternal consumption, and can either be supplemented or consumed through foods.
Fish is also a food to seek out, particularly for the Fish Oil content which is associated with increased offspring intelligence in several animal models. Caution should be taken when considering mercury though, as it is a contaminant in some foods and fish oil products and is negatively associated (bad) for brain development.
Attempt to exclude predatory fish such as shark, or long living fish and species such as albacore tuna, due to their higher mercury content.
Seek shorter living and non-predatory fish such as sardines, mackeral, and herring for the Fish Oil content and lesser mercury content. These select fish are also high in fat content and thus the beneficial omega-3 fatty acids (whereas leaner fish, like tilapia or tuna, have less overall omega-3s).
If not already prescribed by a Medical professional, one should consider taking a Folate supplement to reduce the risk of Neural Tube Defects (NTDs).
There have also been many benefits associated with an increased Choline intake, which can be supplemented or consumed through animal products (mostly through eggs). It should be noted that these have only been seen with Choline, and the similar compound DMAE is actually harmful.
Ginger, usually either in pills or made at home from ground up root (in the form of tea) is demonstrated effective in reducing morning sickness; mostly nausea but sometimes vomiting frequency as well. It has been shown safe for up to 14 weeks usage in pregnant women, so it should be considered to be used as needed during pregnancy.
There are many supplements out there that are 'teratogenic', which is a term used to indicate a compound that is able to disrupt growth and development. For unborn children, they can potentially cause birth defects.
The most well known teratogen is Thalidomide, which is no longer available. Not all teratogens are potent, and there is a chance that ingestion of a compound known to be teratogenic may not actually harm a fetus. For cautionary reasons, it is advised that women expecting a baby do not take or otherwise discontinue usage of any compounds linked to teratogenicity. These compounds include:
Some other compounds are 'Abortifacients' and cause contractions of the wall of the uterus. In worst case scenarios, they may cause premature birth and should also be avoided unless otherwise recommended by a Medical Professional, these include: