Introduction:
Type 1 Diabetes Mellitus (T1DM), an autoimmune disorder requiring continuous glucose regulation, induces significant metabolic and physiological adaptations that affect maternal health and fetal development. Poor glycemic control is associated with an increased risk of complications such as preeclampsia, intrauterine growth restriction, and congenital anomalies. This study explores two primary research questions: 1) What are the effects of pre-existing T1DM on pregnancy outcomes? 2) Does continuous glucose monitoring (CGM) improve perinatal outcomes in pregnant women with T1DM?

Methodology:
Α systematic search was conducted using the keywords "T1D, incidence, neonate, pre- existing T1D, pregnancy, maternal, gestation" and the Boolean logic search algorithm (AND/OR/NOT) as follows: ("Type 1 Diabetes" OR "T1DM" OR "insulin-dependent diabetes") AND ("pregnancy" OR "maternal" OR "gestation" OR "pregnant women") AND ("effects" OR "outcomes" OR "impact") NOT ("Type 2 Diabetes" OR "gestational diabetes" OR "GDM"). The systematic review was carried out following the PRISMA guidelines. The initial search yielded a total of 2,264 records from PubMed and Google Scholar databases. The evaluation of studies led to the inclusion of 11 articles that addressed the research questions.

Results:
Findings emphasize that strict glycemic control, particularly through the use of CGM, reduces glucose fluctuations, improves perinatal outcomes, and minimizes the risk of complications such as preeclampsia, macrosomia, and neonatal hypoglycemia.

Conclusions:
The conclusions highlight the importance of perinatal care for women with T1DM and the use of innovative technologies. The review demonstrated that while CGM significantly enhances glucose monitoring and management, as evidenced by improved HbA1c levels, Time in Range (TIR), and reduced glycemic variability, its direct impact on perinatal outcomes has yet to be fully established.