If a woman becomes pregnant while an Implanon (etonogestrel) implant is still in place, how should the pregnancy be managed and should the implant be removed?

Pregnancy with Implanon In Situ: Management

If pregnancy occurs with an Implanon (etonogestrel) implant in place, the implant should be removed as soon as possible, though available evidence suggests no increased risk of fetal harm if it remains.

Immediate Management Steps

Confirm Pregnancy and Assess Location

• Perform ultrasound to confirm intrauterine pregnancy and establish gestational dating
• Rule out ectopic pregnancy, as rare cases have been reported with progestin-only contraception 1, 2
• Note that most pregnancies with implants in situ occur due to insertion errors (implant not actually placed) rather than true contraceptive failure 3

Implant Removal Decision

Remove the implant promptly if:

• The pregnancy is desired and will be continued
• The patient requests removal
• The implant can be easily located and removed

Key counseling points:

• While theoretical concerns exist about hormonal exposure to the fetus, no teratogenic effects or adverse pregnancy outcomes have been documented in case reports of first-trimester exposure 4
• One case report documented successful continuation of pregnancy with implant left in place throughout gestation, resulting in normal maternal and neonatal outcomes 4
• However, this represents limited data, and removal remains the standard recommendation

Clinical Reasoning

The 2013 U.S. Selected Practice Recommendations acknowledge that when providers are uncertain about pregnancy status, "the benefits of starting the implant likely exceed any risk" 5. This suggests the etonogestrel exposure itself carries minimal fetal risk. However, there is insufficient evidence to recommend intentionally leaving the implant in place during a desired pregnancy.

Important Considerations

Timing of conception:

• Use ultrasound dating to determine if conception occurred before or after implant placement
• In reported pregnancy cases, ultrasound dating often reveals conception occurred days before the implant was placed or due to insertion failure 2, 6

Ectopic pregnancy risk:

• While overall pregnancy rates with implants are extremely low (<1%), when pregnancy does occur, consider ectopic location
• Both intrauterine and tubal ectopic pregnancies have been documented with implants in situ 1, 2

Follow-Up After Removal

• Provide alternative contraception counseling if pregnancy is not continued
• Offer immediate replacement of the implant postpartum or post-abortion if desired 7
• Counsel that the removed implant should be examined to confirm it was intact and properly placed

Common Pitfalls to Avoid

1. Assuming implant failure without verification: Most "pregnancies with implants" are actually due to insertion errors where no implant was placed 3
2. Delaying ectopic pregnancy evaluation: Don't assume intrauterine pregnancy without ultrasound confirmation
3. Failing to counsel about postpartum contraception: The immediate postpartum period is ideal for implant placement if desired 8, 7

Bottom Line Algorithm

1. Positive pregnancy test with implant → Ultrasound for dating and location
2. Confirm implant is actually present → Physical examination and imaging if needed
3. Ectopic ruled out → Remove implant if easily accessible
4. Counsel patient → Limited data shows no documented fetal harm, but removal is standard practice
5. Document → Intact implant removal and gestational dating
6. Plan postpartum contraception → Offer immediate replacement if desired 8

The evidence base consists primarily of case reports and pharmacovigilance data rather than controlled studies, but consistently shows no pattern of teratogenicity with etonogestrel exposure 4, 3.