Pregestational type 1 (T1DM) and type 2 (T2DM) diabetes mellitus and gestational diabetes mellitus (GDM) are associated with increased rates of adverse maternal and neonatal outcomes. Adverse outcomes are more common in women with pregestational diabetes compared to GDM; although, conflicting results have been reported. This systematic review aims to summarise and synthesise studies that have compared adverse pregnancy outcomes in pregnancies complicated by pregestational diabetes and GDM. Three databases, Pubmed, EBSCOhost and Scopus were searched to identify studies that compared adverse outcomes in pregnancies complicated by pregestational T1DM and T2DM, and GDM. A total of 20 studies met the inclusion criteria and are included in this systematic review. Thirteen pregnancy outcomes including caesarean section, preterm birth, congenital anomalies, pre-eclampsia, neonatal hypoglycaemia, macrosomia, neonatal intensive care unit admission, stillbirth, Apgar score, large for gestational age, induction of labour, respiratory distress syndrome and miscarriages were compared. Findings from this review confirm that pregestational diabetes is associated with more frequent pregnancy complications than GDM. Taken together, this review highlights the risks posed by all types of maternal diabetes and the need to improve care and educate women on the importance of maintaining optimal glycaemic control to mitigate these risks.

Adiponectin is an adipocyte-derived hormone that plays a critical role in energy homeostasis, mainly attributed to its insulin-sensitizing properties. Accumulating studies have reported that adiponectin concentrations are decreased during metabolic diseases, such as obesity and type 2 diabetes, with an emerging body of evidence providing support for its use as a biomarker for pregnancy complications. The identification of maternal factors that could predict the outcome of compromised pregnancies could act as valuable tools that allow the early recognition of high-risk pregnancies, facilitating close follow-up and prevention of pregnancy complications in mother and child. In this review we consider the role of adiponectin as a potential biomarker of disorders associated with pregnancy. We discuss common disorders associated with pregnancy (gestational diabetes mellitus, preeclampsia, preterm birth and abnormal intrauterine growth) and highlight studies that have investigated the potential of adiponectin to serve as biomarkers for these disorders. We conclude the review by recommending strategies to consider for future research.

Diabetes in pregnancy increases the risk of adverse perinatal outcomes for mother and child, with severity influenced by the type of diabetes and degree of hyperglycemia. This study aimed to identify circulating microRNAs (miRNAs) associated with different types of diabetes in pregnancy. Serum miRNAs were profiled in pregnant South African women with type 1 diabetes (T1DM), type 2 diabetes (T2DM), gestational diabetes (GDM), and normoglycemia using PCR arrays (n = 15). Differentially expressed miRNAs were validated in pregnant South African women (n = 167), and a separate cohort of Spanish pregnant women with T1DM and T2DM (n = 48). PCR arrays showed significant differential expression for miR-19b-3p (↓ 9.8-fold; p = 0.033) in GDM, miR-20a-5p (↓ 4.5-fold; p = 0.047) in T1DM, and miR-29a-3p (↑ 1.8-fold; p = 0.002) in T2DM compared to normoglycemia. Screening in the larger cohort showed lower expression of miR-20a-5p (↓ 2-fold; p = 0.013) in GDM and miR-30d-5p (↓ 2.1-fold; p = 0.032) in T1DM compared to normoglycemia. Additionally, miR-20a-5p levels were higher in women with T2DM compared to those with GDM (↑ 2.5-fold; p = 0.019). Our findings show that miRNA profiles are largely consistent across different types of diabetes in pregnancy, suggesting that hyperglycemia plays a key role in shaping miRNA expressions. Moreover, the identification of several shared gene targets suggests common underlying pathophysiological mechanisms.