Background Lymphangioleiomyomatosis (LAM) is a rare disease that almost exclusively affects women of reproductive age. Patients are warned of the increased risks if they become pregnant. However, information on pregnancy in patients after the diagnosis of LAM is limited. Methods Patients were collected from the LAM registry study at Peking Union Medical College Hospital, Beijing, China. Patients with a history of pregnancy after the diagnosis of LAM were included. Medical records were reviewed, and baseline information and data during and after pregnancy were collected in May 2018. Results Thirty patients with a total of 34 pregnancies after the diagnosis of LAM were included. Livebirth, spontaneous abortion and induced abortion occurred in 10, 6 and 18 pregnancies, respectively. Sirolimus treatment was common (17/34). A total of 6/10, 5/6, and 6/18 patients with livebirths, spontaneous abortions, and induced abortions respectively, had a history of sirolimus treatment. Ten pregnancies (29.4%) had LAM-associated complications during pregnancy, including the exacerbation of dyspnea in 7 patients, pneumothorax in 3 patients (2 resulting in induced abortion and 1 successful parturition), and spontaneous bleeding of renal angiomyolipomas in 2 patients (both having successful parturition). No chylothorax was found during pregnancy. There were six pregnancies in six patients (17.6%) who had a history of livebirth after sirolimus treatment for LAM (all having successful parturition and healthy infants); two of these patients reported exacerbated dyspnea after parturition compared with before pregnancy. Conclusions Patients with LAM, especially those taking sirolimus before pregnancy, were at a higher risk of spontaneous abortion. Complications such as pneumothorax, bleeding of renal angiomyolipoma, and exacerbated dyspnea during pregnancy were common. In patients without spontaneous abortion, sirolimus discontinuation before or during pregnancy did not lead to increased adverse neonatal outcomes.