Not too much

Consume in moderate amounts.

Basil

Excessive quantities can cause a build up of toxic oils. In food is fine, but should not be consumed in concentrated or medicinal forms.

Source
Safe

Bay Leaf

Reportedly aids flow of breast milk but historically used as an abortifacient (substance to induce abortions) in large quantities.

Source
Careful

Caraway

In large quantities it can cause uterine contractions.

Source
Careful

Carp

Carp can contain moderate levels of mercury, and should only be eaten in strictly limited quantities.
Source
Careful

Coffee

Do not have more than 200mg of caffeine a day.

Source
Careful

Daikon Radish

Large quantities can cause digestive tract irritation.
Source
Safe

Fenugreek

Has been used to induce labour and is considered to be an emmenagogue.

Source
Careful

Gingko Biloba

Excessive quantities can be toxic.
Source
Safe

Herbal Tea

There's little information on the safety of herbal and green teas in pregnancy, so it's best to drink them in moderation.

Green tea contains caffeine.

Source
Careful

Jellied Eels

Jellied eels are cooked during the preparation process, but do contain high quantities of vitamin A so don't eat too many.

Safe

Kola Nut

Kola nuts contain caffeine.

Safe

Lemongrass

Safe in food, unsafe in medicinal or concentrated forms.

Source
Careful

Mastic

As a gum, mastic is used widely in Mediterranean dishes and desserts (including Turkish Delight). It is also used as a chewing gum. Avoid the leaf, especially in the first trimester.
Source
Careful

Moonfish (Opah, Cusk)

Only eat this once a fortnight to prevent a build up of mercury.
Source
Careful

Pilchard

Pilchards are classed as oily (and may contain chemical pollutants) and you shouldn't eat more than two portions a week if you're pregnant.
Source
Careful

Potato

Too much potato consumption during pregnancy has been linked to diabetes.
Source
Safe

Rice

All varieties of rice are generally safe, but be careful about consuming excessive quantities as a build up of normally safe levels of arsenic can be harmful to unborn babies.
Source
Safe

Salmon

All varieties of salmon (in all preparations - i.e. smoked, canned, fresh) are considered low in mercury. However, because they are oily, pregnant women shouldn't consume more than two portions per week to avoid a build up of pollutants.
Careful

Sanddab

Do not have more than two or three times a week.
Source
Careful

Sardine

Due to their oily nature, sardines can contain other pollutants. Sardines are fine to consume while pregnant, but don't have more than two portions a week.
Source
Careful

Sea Bass

Don't have this fish more than twice a week as they can contain similar pollutants to oily fish. Infrequent consumption is perfectly fine.
Source
Safe
Safe

Snapper

Snapper may contain moderate levels of mercury. It's best avoided, but a few small portions a month should be fine.
Careful

Sorrel

Contains oxalic acid, which is harmful in large quantities.

Careful

Sprat

Sprats are oily and should therefore only be eaten (at most) twice a week to avoid build-ups of potentially harmful contaminants.
Careful

Sturgeon

Limit consumption to two portions per week to avoid potentially harmful levels of pollutants.
Source
Careful

Trout

This oily fish should not be consumed more than twice a week.
Source
Careful

Tuna (Albacore, Yellowfin, Bigeye, Skipjack, Bluefin)

Tuna can contain high levels of mercury and when it's fresh it is also considered oily. Don't eat more than two medium-sized portions of fresh tuna (or more than four cans of canned tuna) a week.
Source
Careful

Turbot

Don't eat more than two portions a week because it could have similar levels of pollutants as oily fish.
Source
Careful

Wahoo

No more than once every two weeks.
Source
Careful

Whitebait

Don't eat this oily fish more than twice a week.
Careful