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If you were sexually active after insertion of IUD (within first few weeks), then chances of pregnancy cannot be ruled out. Hormonal contraceptive measures usually start giving you effective protection after about 3-4 weeks of regular use. It is recommended that you use additional protection while having intercourse during this time. If you suspect to be pregnant, look out for development of any other new symptoms suggestive of early pregnancy. You should consider visiting your doctor/gynecologist for further evaluation and assistance. If pregnancy is suspected, a blood/serum HCG test done would be helpful to confirm/rule out pregnancy accurately.
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