The Krogan will frequently mention having many stillborn babies as a result of the "genophage" which renders most of the species sterile or causes miscarriage/stillbirths.
During a sidequest dealing with a distraught abuse victim, the Renegade option to resolve the quest is to forcibly inject her with a sedative. If done right, she's given a sleeping pill, which she takes willingly.
The Prothean Beacon at the beginning. It's literally some "Indianna Jones"-level valuable in-universe. It explodes after being sabotaged/booby-trapped.
If your Shepard has a colonist background, you will receive a side quest at the citadel where you talk to Talitha, a girl named who was captured and traumatized at the hands of Batarian slavers from a young age.
A political attache is addicted to a drug that, while not outright banned, is tightly controlled. He begs Shepard to use their Spectre status to get him an advance on his next ration. He can be talked into getting himself straight, however.
One sidequest involves a consul who asks Sheperd to abuse their authority to get him an additional dose of a mind-enhancing drug he's taken his allotment of. Sheperd must either do so or talk him into getting off the Sapho.
A side quest makes it possible for you to kill monkey-like creatures on a planet while looking for a missing device hidden on one of them. Killing them generates reactions of approval/disapproval depending on which squadmates you bring. (To clarify, you can complete the quest without hurting any of them)
Rachni, a species of arachnoid creatures, can be seen during the game, but they are so alien that it'd probably be difficult that they trigger any arachnophobe.
If you use incendiary ammo, this burns your opponents when you shoot them and causes their body to disintegrate upon their death. It’s generally not considered to be very graphic though.
Matriarch Benezia, a mother of one of your crew members, is required to be killed. There are other references to parents dying through the game and series.
Occasional morality choices using the left and right triggers can cause unexpected responses, but this is animation and congruence, not intentional jump scares.
In the Mission "Feros: Geth Attack"; after dealing with the colonists and going on your way back to the Normandy (near the end of the mission), you'll find a new type of enemy. One of the attacks available for this enemy is puking a green-ish "pus" that will poison the main character. The enemies will also explode with this "liquid" on each hit and on death. After some time you'll get a cutscene where you'll go downstairs and meet a giant mouth thing hanging for the ceiling; A humanoid entity will come out of their mouth. The sound is calm but slimy because it's a slimy creature, so if you feel like you'll be ok, just close your eyes until you hear this new character speak.
Talitha, a traumatized girl you'll encounter if you choose the Colonist background, can be considered a violent threat (though objectively she does not hurt anyone). If anything, there's violence toward mentally ill people like in this case. One of the characters says there is a sniper watching her in case she acts out. If you choose the extreme renegade option you can request to have her killed ("you should take her out before she hurts anyone else") followed by an offscreen gunshot.
On Eden Prime, you have the option to encounter hidden NPCs. Manuel, one of the NPCs, experiences a mental breakdown and expresses an anxious outlook about the future. Additionally, the protagonist has the option to not be very kind about it.
It is a possibility, if your Paragon/Renegade score is high enough, for you to be able to talk Saren into suicide instead of fighting him in the final mission. He uses a gun and is rather fast, but it's still there. In addition, someone goes on a mission on Virmire not expecting to survive.
If the "sole survivor" background is chosen for Shepard, there will be occasional implications that Shepard experiences PTSD symptoms as a result of the event in their past.
In the game, a type of alien called Krogan are affected by a disease that causes only a few babies to be able to hatch. While it isn't exactly miscarrying, I would consider it similar enough to warrant a caution to anyone sensitive to miscarriage.
Yes, but not about different specific groups of humans. The hate speech in Mass Effect is done by or about aliens, making bigoted comments about other aliens, including humans as a whole.
During one mission the character Harkin will sexually harass you with lewd comments if you’re playing as a woman. Even ignoring that said moment takes place in a strip club where even the player can ogle the dancers
Aside from a strip club, the only sexual content you're going to see is if you choose to pursue a romance. An all cases, the only body parts shown are butts. You will never see a nipple or genital in Mass Effect 1.