Jennifer Salcedo and Aparna Sridhar
History of present illness
An 18-year-old gravida 0 woman presents to your urgent care clinic with complaint of three days of moderate dark vaginal bleeding accompanied by mild pelvic cramping. She had a Nexplanon®(etonogestrel) contraceptive implant placed three months ago for long-acting reversible contraception after she had difficulty remembering to take oral contraceptive pills as prescribed. She has a long-term history of irregular menstrual cycles. She is uncertain of her last menstrual period, but believes it was a few weeks prior to the Nexplanon placement.
Urine pregnancy testing performed in the office before the Nexplanon placement was negative.
Her past medical history is unremarkable. She takes no other medications. She has never had surgery. She is sexually active with a single partner.
Due to a recent change in insurance, she is unable to follow-up with her previous provider and wants reassurance that her current symptoms are normal before she leaves to travel for the summer.
Physical examination
General appearance:Well-developed, well-nourished woman who is in no distress
Vital signs:
Temperature: 37.0°C Pulse: 86 beats/min
Blood pressure: 106/70 mmHg Respiratory rate: 18 breaths/min Oxygen saturation: 100% on room air
Extremities:Nexplanon rod palpable in left upper arm, approximately 8 cm proximal to the medial epicondyle in the intermuscular groove
Abdomen:Soft, nontender
External genitalia:Unremarkable without lesions Vagina:Approximately 10 cc dark-appearing blood in the vault with one dime-sized clot. No mucopurulent discharge
Cervix:Closed without lesions. No cervical motion tenderness
Uterus:Fourteen-week size, mobile, mid-position, nontender
Adnexa:Nontender without masses
Laboratory studies:
Urine pregnancy test: Positive CBC: Within normal limits Blood type: O positive
Imaging:Transabdominal pelvic ultrasound shows a singleton intrauterine pregnancy consistent with 14 weeks and 1 day, posterior placenta without previa, cardiac motion present, uterus and cervix within normal limits, ovaries not clearly visualized, no adnexal masses seen, and no pelvic freefluid
How would you manage this patient?
The patient had a Nexplanon contraceptive implant placed a few weeks following her last menstrual period, prior to which she was irregularly using oral contraceptive pills. Inadequately protected intercourse took place prior to Nexplanon initiation, resulting in a pregnancy that was too early to be detected by the urine preg- nancy testing performed in the office. The patient did not realize that her amenorrhea could be the result of pregnancy, given her history of irregular menstrual cycles and expectations for irregular bleeding with Nexplanon use. She now presents with a threatened abortion at 14 weeks’gestation, a complication unre- lated to Nexplanon use. She needs referral for pregnancy options counseling and follow-up. Unlike an intrauterine device (IUD), the Nexplanon implant presents no threat to the ongoing preg- nancy, and removal may be deferred to follow-up.
Implantable contraception
Nexplanon is a single-rod subdermal contraceptive implant con- taining a core of 68 mg of etonogestrel, a progestin, which is released over a period of 3 years. It is 4 cm in length and 2 mm in diameter. Nexplanon is a radiopaque second-generation version of the original etonogestrel implant, Implanon®, which was approved in the United States in 2006. It is distributed in a specially designed preloaded applicator and inserted under local anesthesia. All healthcare providers who provide Nexplanon insertion and removal must complete a formal training program administered by the device manufacturer [1]. Its primary mech- anism of action is suppression of ovulation. It is the most effective method of reversible contraception, with a failure rate of 0.05% during thefirst year of use [2]. Its noncontraceptive benefits include improvement of dysmenorrhea and decreased pelvic pain related to endometriosis [3].
Acute Care and Emergency Gynecology, ed. David Chelmow, Christine R. Isaacs and Ashley Carroll. Published by Cambridge University Press.
© Cambridge University Press 2015.
Changes in menstrual bleeding patterns are common and may include amenorrhea, infrequent, frequent, or prolonged bleeding. However, Nexplanon users experience fewer mean bleeding and spotting days per cycle than women with natural menstrual cycles. Women with favorable bleeding profiles during the first three months of implant use are likely to continue such bleeding patterns, while those with unfavorable bleeding patterns have a 50% chance of those patterns improv- ing. Women with lower body weight have fewer bleeding and spotting days with implant use than women with higher body weight [4]. The 1-year continuation rate for implant users is 84%, which compares favorably to the 67% annual continu- ation rate of oral contraceptive pill users [2].
According to the US Medical Eligibility for Contraceptive Use [5], use of the etonogestrel contraceptive implant by most women is category 1, meaning there are no restrictions for its use. There are few women for whom the theoretical risks of implant use are thought to outweigh the anticipated benefits.
Such women include: those in whom ischemic heart disease or stroke begins or worsens during implant use; lupus and posi- tive or unknown antiphospholipid antibodies; migraines with aura that begins or worsens during implant use; undiagnosed abnormal vaginal bleeding suspicious for malignancy; history of breast cancer in remission for at leastfive years; and severe liver disease or cancer. Implant use is only absolutely contra- indicated for women with current breast cancer. There is no known harm to the woman, the course of her pregnancy, or the fetus if systemic progestin-only contraception (pill, injection, implant) is inadvertently used during pregnancy [5].
According to the US Selected Practice Recommendations for Contraceptive Use [6], a contraceptive implant can be inserted at any time when it is reasonably certain that the woman is not pregnant. A healthcare provider can be reason- ably certain a woman is not pregnant if she lacks signs and symptoms of pregnancy and meets any of the following cri- teria: she is within seven days from the start of normal menses;
has not has intercourse since the start of the last normal menses; has been correctly and consistently using a reliable method of contraception; is within seven days of a spontan- eous or induced abortion; is within four weeks postpartum; or is exclusively breast-feeding and amenorrheic within six months of birth. In these circumstances, a pregnancy test is not required, but may be ordered based on clinical judgment.
If a woman is not within five days of the start of her last menses, a back-up method of contraception, such as condoms, should be used for seven days following implant insertion [6].
In this case, at the time of Nexplanon insertion the provider
could not be reasonably certain the woman was not pregnant.
If the decision had been made with the patient to proceed with Nexplanon insertion, the possibility of an early undetected pregnancy should have been discussed, and a plan made for follow-up pregnancy testing.
Urine pregnancy testing
Both qualitative urine pregnancy point-of-care (POC) tests used in medical settings and those purchased over-the-counter for home testing demonstrate wide variability in their sensitiv- ity for detecting human chorionic gonadotropin (hCG). This variability is even more substantial when it comes to detecting the variants of hCG, such as hyperglycosylated hCG, that are common and variably excreted in early pregnancy [7]. POC tests demonstrate sensitivities of approximately 40–77% for detecting pregnancy the day of missed menses, and have been found to have lower sensitivities than available home tests [8].
Specifically, POC tests have poor sensitivity at hCG concen- trations of 20–300 IU/L, and are correct only 50% of the time when evaluating urine with hCG in this range [9]. Home tests demonstrate a sensitivity of 55–100% in detecting pregnancy on the day of missed menses. At least 1 home pregnancy test has demonstrated the ability to detect 25% of pregnancies 6 days prior to missed menses and 74% of pregnancies 3 days prior to missed menses. However, it is important to note that at 6 days, 5 days, and 4 days prior to missed menses, only 29%, 40%, and 76% of pregnancies, respectively, have implanted and are releasing hCG [8]. In this case, the Nexplanon was likely placed during the woman’s periovulatory period, during which time neither home nor POC pregnancy tests would be expected to detect the conception.
Key teaching points
The Nexplanon implant is the most effective reversible method of contraception.
Pregnancy should always be suspected in women who present with abnormal bleeding or pregnancy-related symptoms, even if the patient has a history of highly effective contraception use or sterilization.
Qualitative urine pregnancy testing is inconsistently reliable until several days after missed menses.
If a healthcare provider cannot be reasonably certain that a woman is not pregnant at the time of contraception initiation, emergency contraception should be offered, if appropriate, and a plan for follow-up pregnancy testing should be made.
References
1. American College of Obstetricians and Gynecologists. Long-acting reversible contraception: Implants and intrauterine devices. Practice Bulletin No. 121.Obstet Gynecol2011;118:184–96.
2. Trussell L. Contraceptive failure in the United States.Contraception
2011;83:397–404.
3. Walch K, Unfried G, Huber J, et al.
Implanon versus medroxyprogesterone acetate: effects on pain scores in patients
with symptomatic endometriosis–a pilot study.Contraception2009;79:
29–34.
4. Mansour D, Korver T, Marintcheva- Petrova M, Fraser IS. The effects of Implanon on menstrual bleeding Case 42: An 18-year-old woman with long-acting reversible contraception and new-onset bleeding
patterns.Eur J Contracept Reprod Health Care2008;13(Suppl 1):13–28.
5. Centers for Disease Control and Prevention. US medical eligibility criteria for contraceptive use.MMWR 2010;59(RR-4):1–86.
6. Centers for Disease Control and Prevention. US selected practice
recommendations for contraceptive use.MMWR2013;62(RR-5):1–46.
7. Cervinski MA, Lockwood CM, Ferguson AM, et al. Qualitative point- of-care and over-the-counter urine hCG devices differently detect the hCG variants of early pregnancy.Clinica Chimica Acta2009;406:81–5.
8. Cole LA. The hCG assay or pregnancy test.Clin Chem Lab Med2012;50:
617–30.
9. Green DN, Schmidt RL, Kamer SM, et al. Limitations in qualitative point of care hCG tests for detecting early pregnancy.Clinica Chimica Acta 2013;415:317–21.