Objective: Tea lovers are increasing worldwide. We hope that this report is the first to discuss the possible impacts of high black tea consumption on gestational weight gain (GWG) and birth parameters. Methods: Throughout one year, a total of 7,063 pregnant ladies coming for first antenatal visit were screened in a major tertiary center. Of them, 1,138 were involved and divided according to their preference into 3 groups: excessive tea (ET), usual tea (UT), and mixed beverages group. The study included women who gave birth to healthy neonates. Results: The rate of ET consumption was 4.13% with a total of 41 cases. The UT group (controls) comprised 94 women. ET was significantly associated (P<0.05) with maternal age, parity, occupation, smoking, and poor GWG starting from 30 weeks’ gestation until delivery, low birth weight, and small for gestational age (SGA). Poor GWG had a higher relative risk (with 95% confidence interval) in the ET group than in the UT group in crude (1.84 [0.85–2.43]) and risk adjusted models (1.25 [0.28–2.26]). Further, similar results were obtained for SGA in the crude and 3 adjusted models, where the first model was adjusted for bio-obstetrical variables, the second for social parameters, and the third for all factors included in the previous models (1.53 [0.62–2.81], 1.52 [0.71–2.50], and 1.46 [0.78–2.39]), respectively. Conclusion Consumption of large amounts of daily black tea during pregnancy (≥1,500 mL) is a significant cause of poor GWG and SGA.