Abstract
<title>Abstract</title> <p>Background Congenital tuberculosis (CTB) is rare but often severe. Although CTB is usually associated with clinically apparent maternal tuberculosis, maternal infection may be asymptomatic, particularly during pregnancy and after assisted reproduction. The clinical spectrum of CTB arising from occult maternal tuberculosis in IVF-ET twin pregnancies remains poorly described. Case presentation: We report two IVF-ET twin pregnancies in which the mothers had no tuberculosis-related symptoms during the perinatal period but the fetuses and neonates developed markedly divergent outcomes. In the first pregnancy, suspected hematogenous dissemination from maternal pulmonary tuberculosis was associated with delayed postnatal CTB in both twins. The infants were diagnosed at approximately 3 months of age based on Xpert testing and molecular pathogen detection, responded well to anti-tuberculosis therapy, and showed favorable growth and development during 3 years of follow-up. In the second pregnancy, suspected endometrial or localized placental tuberculosis was associated with intrauterine fetal death in one twin and fatal extreme prematurity with severe infection in the co-twin. Mycobacterium tuberculosis was detected in maternal uterine secretions by metagenomic next-generation sequencing 12 days after delivery, and tuberculosis DNA was detected in neonatal respiratory secretions. Conclusions Occult maternal tuberculosis may cause a wide spectrum of CTB outcomes, from fetal death and fatal extreme prematurity to delayed postnatal disease with good recovery after treatment. These cases support tuberculosis screening before IVF-ET and systematic placental or uterine mycobacterial testing after unexplained stillbirth, extreme preterm birth, fetal growth restriction, or severe neonatal infection.</p>