Background: To evaluate the effect of distance, professional behaviour education and guidance on reducing adverse pregnancy outcomes in women with gestational diabetes mellitus (GDM). Methods: Women with GDM who had undergone regular prenatal care and gave birth at Jinshan Branch of Shanghai Sixth People’s Hospital from January 2019 to October 2020 were enrolled. A random number table method was utilized to divide the patients into a control group (168 cases) and an intervention group (182 cases). In the control group, routine prenatal education was conducted, while in the intervention group, in addition to routine prenatal education, providers used video and the WeChat public platform to regularly impart knowledge and behaviour education to women with GDM and supervise the implementation of their actions. The pregnancy outcomes of the two groups were compared. Results: ① Fasting plasma glucose (FPG), 2-hour postprandial blood glucose (2hPG) and glycohemoglobin (HbAlc) in the intervention group were significantly lower than that of the control group (p 0.05). ② In the intervention group, the thyroid peroxidase antibody (TPOAb) positive rate was lower and free thyroxine (FT4) was higher than that in the control group (p > 0.05). The vaginal pH in the intervention group was significantly higher than that of the control group. ③ Thyroid-stimulating hormone (TSH), weight gain during pregnancy, incidences of preeclampsia, polyhydramnios, preterm premature rupture of membranes (PPROM), premature rupture of membranes (PROM), caesarean section, puerperal infection, amniotic fluid pollution chorioamnionitis, macrosomia, large for gestational age infant, neonatal care, neonatal hypoglycaemia, neonatal pneumonia, detection rates of bacterial vaginosis (BV), vulvovaginal candidiasis (VVC), Ureaplasma urealyticum (UU), Group B streptococcus (GBS), cleanliness III/IV and positive rates of hydrogen peroxide, neuraminidase and leukocyte esterase were all significantly lower in the intervention group than those in the control group (p 0.05) and relative risk (RR) 1. ④ The rates of trichomonas vaginitis (TV), Neisseria gonorrhoeae, chlamydia trachomatis (CT), positive rates of N-acetyl-D-glucosaminidase (NAG), and proline aminopeptidase (PA), and the incidences of oligohydramnios, foetal growth restriction (FGR), placenta previa, placental abruption, foetal distress in utero, postpartum haemorrhage, preterm infant, neonatal Apgar score less than 7 at one minute, neonatal abnormality, neonatal death, small for gestational age and hyperbilirubinemia were lower in the intervention group than those in the control group (p > 0.05). Conclusions: WeChat group and other online intervention measures were adopted for women with GDM. These are simple interventions which can automatically upload, classify, and analyse data. An increased use of telemedicine can closely supervise the intervention, adjust the personalized plan at any time, effectively control blood sugar levels, maintain vaginal microecological balance and reduce the occurrence of adverse pregnancy outcomes.