<unk><unk> s (IUDs) are one of the most effective contraceptive methods
T-shaped<unk>  inserted through cervix, can be used for up to 3-12 years
Serious<unk>  are rare, <1% of women with IUDs
Copper IUD (Paraguard):
lasts up to 12 years, no hormones, usually cheaper
tend to cause more side effects (heavy/irregular menses, pelvic pain)
also extremely effective as emergency contraception if inserted within 120 hours of unprotected sex
Hormonal IUDs (Mirena, Liletta, Mirena, Skyla, Kyleena): secrete small amount of progestin (levonorgestrel)
MIrena effective up to 6 years, the others for 3-5 years
Menses tend to get significantly lighter or disappear altogether after the first few months
Very little progestin absorbed systemically, so women tend NOT to have the hormonal side effects or increased DVT/PE risk associated with oral contraceptives
lasts up to 12 years, no hormones, usually cheaper
tend to cause more side effects (heavy/irregular menses, pelvic pain)
also extremely effective as emergency contraception if inserted within 120 hours of unprotected sex
MIrena effective up to 6 years, the others for 3-5 years
Menses tend to get significantly lighter or disappear altogether after the first few months
Very little progestin absorbed systemically, so women tend NOT to have the hormonal side effects or increased DVT/PE risk associated with oral contraceptives
Intrauterine device complications
Comorbid diseases in pregnancy
Pregnancy 
Trauma in pregnancy
Vaginal trauma
Dysfunctional uterine bleeding
Preterm labor
Postpartum hemorrhage