Can I be reasonably certain this patient is not pregnant and place a LNG-IUD?
Updated: Feb 25
Client presents to clinic for LNG IUD. Client has used condoms 100% in the last two weeks and has a negative urine pregnancy test (ucg) on day of visit. Would you insert a LNG IUD? She has no symptoms of pregnancy and has used condoms 100% x 2 weeks. Going by the CDC Selected Practice Recommendations, 'Being Reasonably Certain a Woman is Not Pregnant' criteria of no pregnancy signs or symptoms PLUS correctly and consistently using a reliable method of contraception, is 2 weeks a long enough time period to use, provided the UCG test detects HCG at 20mIU or greater? K.C.
Thank you for presenting this common and challenging situation. I assume your patient is not on her period because if so, we could be reasonable sure she isn’t pregnant based on the CDC criteria (first in the list below).
The short answer is you can provide the IUD if the patient is OK assuming a small risk that she may be pregnant - though highly unlikely. In general, two weeks of use of a method consistently and correctly plus a negative pregnancy test should be enough to rule out a pregnancy. But the longer answer below is about weighing all the factors going into making this decision.
In general, we want to provide the most effective method when requested without delay. Regarding insertion of a LNG-IUD, the CDC says this: “In situations in which the health care provider is uncertain whether the woman might be pregnant, the woman should be provided with another contraceptive method to use until the health care provider can be reasonably certain that she is not pregnant and can insert the LNG-IUD.”
A few relevant questions to help determine whether you are reasonably certain your patient is not pregnant:
1) Where in the cycle is she?
2) What happened before these last two weeks? Did she have unprotected intercourse in the two prior weeks?
3) Does your patient have regular menstrual intervals?
You’ve correctly consulted the CDC Selected Practice Recommendations, available here.
Some important considerations:
•The criterion for correctly and consistently using a reliable method should cover a time frame that includes any risk of pregnancy, so a time frame since her last period. In your case, two weeks may not be long enough if she had unprotected intercourse earlier in the cycle depending on where she is in her cycle. The second criterion above is no unprotected sex since her last period.
• The next question is whether condoms are considered “reliable.” The CDC doesn’t define what it considers “reliable.” If condoms were used each time consistently and correctly some may consider that reliable (I would), while others may say condoms should never be considered a reliable method. The perfect use failure rate is 2% in the first year of use and the typical use failure rate is 13%.
• If she had recent unprotected intercourse, within the past five days, you may provide emergency contraception
• Pregnancy tests typically become positive as early as 7-10 days after implantation, so they may often be positive at the time of a missed menstrual period. BUT a negative test does not definitively rule out pregnancy completely. According to CDC, “Some studies have shown that an additional 11 days past the day of expected menses are needed to detect 100% of pregnancies using qualitative tests.”
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