PIP: Uterine perforation is the most serious complication of IUD insertion; the risk is less than 1/1000 insertions for currently available IUDs. Most perforations occur at the time of insertion and the risk is increased in the 4-8 weeks postpartum. It is important to choose an IUD appropriate to the size of the endometrial cavity and to clean the area with an antiseptic solution. When the string is found to be missing, pregnancy must be excluded, and the endometrial cavity explored. Ultrasonography can often determine if the IUD is in the uterus; most IUDs that perforate the uterus are often found in the pelvis. Alterations in vital signs that occur at the time of insertion have been documented in 35-60% of patients; these generally require no therapy. If there are severe vasovagal reactions, treatment with intravenous atropine sulfate 0.4 mg, may be required. Bleeding is the most common reason for IUD removal, but its cause is not extremely clear. Blood loss is greatest with the large inert devices, less with small copper-containing devices, and least with a progesterone-containing IUD. The addition of supplementary iron to the diet and periodic hemoglobin determinations are recommended for IUD users. The risk of pelvic inflammatory disease (PID) is increased in IUD users, ranging from 1.6-10.5 compared with other forms of contraception. Risk is greatest during the 1st few months after insertion but continues to be higher than normal as long as the IUD is used. Studies have shown that women using hormonal or barrier contraceptives have a decreased incidence of PID. For mild infection, tetracycline 500 mg orally 4 times daily suffices; in more severe cases a regimen consisting of an animoglycoside plus penicillin is adequate. The pregnancy rate in IUD users varies between 1.6-5.3/100 women/year. Pregnancy in an IUD-wearer must be considered ectopic until proven otherwise, although the rate of ectopic pregnancy in this group is extremely low. The IUD's protective effect seems to extend to the fallopian tube and is greatest in the 1st and 2nd years of use. Once pregnancy is determined the IUD should be removed; studies have shown that the spontaneous abortion rate with the IUD left in situ is about 50% versus 20-30% with removal or subsequent spontaneous expulsion. Some contraindications to IUD use include acute PID, allergy to heavy metals, bleeding diathesis, cervical stenosis, and uterine myoma.