A 24-year-old woman comes to the office for a routine prenatal visit at 32 weeks gestation. Last week, she was evaluated for postcoital spotting. The cervix was closed, and there was no evidence of preterm labor. Nucleic acid amplification testing (NAAT) performed at that visit was positive for Chlamydia trachomatis. Routine NAAT was negative for C trachomatis at the initial prenatal visit. Today, the patient has no vaginal bleeding, leakage of fluid, or contractions. Fetal movement is normal. She has no chronic medical conditions or previous surgeries. The patient does not use tobacco, alcohol, or illicit drugs. She had 3 sexual partners prior to marriage. She has been in a monogamous relationship with her husband for the last 2 years and is sexually active with him. The patient swims at the local pool regularly but stopped after the episode of vaginal bleeding. Blood pressure is 110/70 mm Hg and pulse is 72/min. Fundal height is 32 cm. Fetal heart rate is 140/min by Doppler ultrasound. Urine dipstick is negative for glucose and protein. The patient is concerned about the results and wonders how she acquired the infection during her pregnancy.
Which of the following is the most appropriate statement to explain the results?

Question

A 24-year-old woman comes to the office for a routine prenatal visit at 32 weeks gestation.  Last week, she was evaluated for postcoital spotting.  The cervix was closed, and there was no evidence of preterm labor.  Nucleic acid amplification testing (NAAT) performed at that visit was positive for Chlamydia trachomatis.  Routine NAAT was negative for C trachomatis at the initial prenatal visit.  Today, the patient has no vaginal bleeding, leakage of fluid, or contractions.  Fetal movement is normal.  She has no chronic medical conditions or previous surgeries.  The patient does not use tobacco, alcohol, or illicit drugs.  She had 3 sexual partners prior to marriage.  She has been in a monogamous relationship with her husband for the last 2 years and is sexually active with him.  The patient swims at the local pool regularly but stopped after the episode of vaginal bleeding.  Blood pressure is 110/70 mm Hg and pulse is 72/min.  Fundal height is 32 cm.  Fetal heart rate is 140/min by Doppler ultrasound.  Urine dipstick is negative for glucose and protein.  The patient is concerned about the results and wonders how she acquired the infection during her pregnancy. 
Which of the following is the most appropriate statement to explain the results?

Quizplus · Accepted Answer

Explanation: 11ec2b69_bfb5_67b6_8f63_a7805d09fa31_MD0005_00 Infection with Chlamydia trachomatis is frequently asymptomatic. Pregnant patients are routinely screened for chlamydia via nucleic acid amplification testing (NAAT) at the initial prenatal visit. High-risk patients (eg, age <25, multiple partners) undergo screening again in the late third trimester. In addition, patients with symptoms suggestive of acute cervicitis, such as postcoital spotting or mucopurulent cervical discharge, are tested with NAAT. mucopurulent cervical discharge NAAT is the preferred test for diagnosing both C trachomatis and Neisseria gonorrhoeae due to its high sensitivity and specificity. NAAT false-positive and false-negative results are rare, and pregnancy does not alter the test's performance (Choices B and D). This patient had negative chlamydia testing at the initial prenatal visit; therefore, the recent positive NAAT is due to newly acquired infection. (Choice A) Although reactivation of herpes simplex virus infection occurs, reactivation of chlamydial infection does not. A positive NAAT for Chlamydia in a patient whose test was previously negative is most consistent with recent transmission and new infection. (Choice C) C trachomatis is sexually transmitted and is not spread from a water source. Educational objective: A negative Chlamydia trachomatis nucleic acid amplification test at the initial prenatal visit followed by a positive test in the third trimester most likely indicates a newly acquired infection during pregnancy. References: Sexually transmitted diseases treatment guidelines, 2015. (http://www.ncbi.nlm.nih.gov/pubmed/26042815) Recommendations for the laboratory-based detection of Chlamydia trachomatis and Neisseria gonorrhoeae-2014. (http://www.ncbi.nlm.nih.gov/pubmed/24622331)

A 24-Year-Old Woman Comes to the Office for a Routine