Worldwide, tuberculosis (TB) is among the top five causes of death for women aged 15-44 years [1]. In 2014, an estimated 480 000 of newly reported TB cases were multidrug-resistant (MDR) TB [1]. Pregnancy is a risk factor for reactivation of TB, but data about multidrug-resistant (MDR)-TB in pregnant women are lacking. There are few data about the efficacy and safety of second-line anti-TB drugs during pregnancy for both the mother and the unborn child [2]. One study from Peru showed a mortality rate of 13% in 38 patients and 13% of these 38 patients were lost to follow-up. Five of the pregnancies ended in spontaneous abortions, and one child was stillborn. Data for pregnant women did not differ from the general MDR-TB population in Peru [2]. To assure efficacy while minimising adverse events, therapeutic drug monitoring (TDM) has been proposed [3]. In TDM of anti-TB drugs, the accurately measured exposure to the drug [4] is evaluated in relation to the minimum inhibitory concentration (MIC) of the offending strain of Mycobacterium tuberculosis [5]. Low drug exposure is associated with an increased risk of treatment failure or with acquired resistance. High drug exposure might result in increased toxicity and adverse events [6]. Little is known about the effects of pregnancy in patients with MDR-TB with regards to the pharmacokinetics of second-line anti-TB drugs [2]. During pregnancy, pharmacokinetic parameters might change over time because of dynamic physiological changes in different stages of pregnancy, leading to inadequate treatment and poor outcome. In this case study, we aimed to describe the pharmacokinetics of moxifloxacin (Mfx) and linezolid (Lzd) during and after pregnancy in a patient with MDR-TB. A 25-year-old HIV-negative female from Somalia presented with a cough of several months' duration. She had arrived in the Netherlands 10 months earlier [7]. Her sister had been diagnosed with TB 12 years ago, and had been treated successfully. Physical examination revealed an enlarged lymph node in her neck. Culture from a fine-needle aspirate yielded M. tuberculosis. The chest radiograph showed no abnormalities; she was started on rifampin, isoniazid, pyrazinamide and ethambutol. Molecular susceptibility testing of the cultured isolate showed mutations in both the rpoB and katG genes. She was diagnosed with MDR-TB and transferred to our TB reference centre at 11 weeks' gestation. The first-line anti-TB drugs were discontinued and we decided to wait for further susceptibility results before starting with-second line anti-TB drugs to avoid giving inactive but potentially toxic drugs to the fetus. We considered it safe to withhold the treatment for some time as lymph node TB is paucibacillary and she was clinically stable without apparent disease activity apart from the nuchal lymph nodes. In vitro phenotypical susceptibility testing was performed, and the isolate appeared resistant to the first-line drugs rifampicin, isoniazid and ethambutol, but susceptible to all injectables, moxifloxacin, prothionamide, ...