Sushi in general is considered safe in pregnancy. The only exception are mercury levels in certain seafoods. Most of the fish in Sushi is safe can can be eaten during pregnancy without health concerns. However, a few of the fish used in sushi may contain too high levels of mercury which could affect the developing fetus, and these kind of fish should be avoided, but there are others that can be safely eaten. 

LOWEST MERCURY: Enjoy two 6-oz servings a week

• Aji (horse mackerel)
• Akagai (ark shell)
• Anago (conger eel)
• Aoyagi (round clam)
• Awabi (abalone)
• Ayu (sweetfish)
• Ebi (shrimp)
• Hamaguri (clam)
• Hamo (pike conger; sea eel)
• Hatahata (sandfish)
• Himo (ark shell)
• Hokkigai (surf clam)
• Hotategai (scallop)
• Ika (squid)
• Ikura (salmon roe)
• Kaibashira (shellfish)
• Kaiware (daikon-radish sprouts)
• Karei (flatfish)
• Kohada (gizzard shad)
• Masago (smelt egg)
• Mirugai (surf clam)
• Nori-tama (egg)
• Sake (salmon)
• Sawara (spanish mackerel)
• Sayori (halfbeak)
• Shako (mantis shrimp)
• Tai (sea bream)
• Tairagai (razor-shell clam)
• Tako (octopus)
• Tamago (egg) Tobikko (flying fish egg)
• Torigai (cockle)
• Tsubugai (shellfish)
• Unagi (freshwater eel)
• Uni (sea urchin roe)

High Mercury: Eat no more than three 6-oz servings a month

• Kajiki (swordfish)
• Saba (mackerel)
• Shark
• Tilefish
• Ahi (yellowfin tuna)
• Buri (adult yellowtail)
• Hamachi (young yellowtail)
• Inada (very young yellowtail)
• Kanpachi (very young yellowtail)
• Katsuo (bonito)
• Maguro (bigeye, bluefin or yellowfin tuna)
• Makjiki (blue marlin)
• Masu (trout)
• Meji (young bigeye, bluefin* or yellowfin tuna)
• Shiro (albacore tuna)
• Toro (bigeye, bluefin or yellowfin tuna)

LOWER MERCURY: Eat no more than six 6-oz servings per month

• Kani (crab)
• Seigo (young sea bass)
• Suzuki (sea bass)

Highest mercury: AVOID

• 
  Chart obtained from the Natural Resource Defense Council (NRDC); data obtained by the FDA and the EPA.Kajiki (swordfish)
• Saba (mackerel)
• Shark
• Tilefish