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Early-onset type 2 diabetes is rising in women of childbearing age, increasing the risk for fetal and maternal complications versus other forms of diabetes.

“Early onset type 2 diabetes (T2D – generally diagnosed prior to the age of 40) is of major concern as its prevalence is increasing rapidly,” researchers wrote in The American Journal of Obstetrics and Gynecology. “It disproportionately affects females, those of non-White ethnicity, and those living in the most deprived communities, meaning it is affecting an increasing proportion of women in their childbearing years.”

In the United States, the March of Dimes estimates that 1% to 2% of women have preexisting diabetes before pregnancy, a number that has been increasing in recent years.

For this systematic review and meta-analysis, Eleanor Scott, MD, and colleagues set out to determine the impact of T2D on pregnancy outcomes versus type 1 diabetes (T1D), gestational diabetes (GDM), and pregnancies not affected by diabetes. Primary outcomes, which were all evaluated among the infants, included congenital anomalies; stillbirths; neonatal and perinatal mortality; birthweight; and rates of large for gestational age (LGA), small for gestational age (SGA), and macrosomia.

Primary Outcomes With T2D in Pregnancy

The analysis included 47 studies. The number of pregnancies in each analysis varied, ranging from 723 to 4,469,053 pregnancies.

When comparing mothers with T2D with other populations, Dr. Scott and colleagues found that:

• Moms with T2D had a smaller chance of an LGA baby compared with moms with T1D but a higher risk for having an SGA baby as well as neonatal and perinatal mortality.
• Moms with T2D had babies that were 80.20 grams lighter, on average, than babies from mothers who had T1D.
• The babies of mothers with T2D had a heightened risk for congenital anomalies, being LGA, and stillbirth and perinatal mortality compared with babies of mothers with gestational diabetes.
• Compared with women with no diabetes, mothers with T2D had a greater likelihood of having a baby with congenital anomalies, as well as perinatal mortality or stillbirth.

Secondary Outcomes With T2D in Pregnancy

Dr. Scott and colleagues also examined secondary outcomes for the babies of mothers with T2D compared with mothers without diabetes, gestational diabetes, and T1D.

Mothers with T1D were more likely to have a preterm birth at less than 37 weeks’ gestation as well as neonatal ICU (NICU) admission. Mothers with T2D were more likely than their counterparts with gestational diabetes to experience pregnancy-induced hypertension, a preterm birth at less than 37 weeks, and preeclampsia.

Compared with mothers without diabetes, pregnant women with T2D were more likely to experience:

• Pregnancy-induced hypertension
• Preeclampsia
• Cesarean delivery
• Preterm births at less than 37 and less than 32 weeks
• Shoulder dystocia
• Neonatal hypoglycemia
• Respiratory distress syndrome
• Fetal hyperbilirubinemia
• Fetal hypocalcemia
• NICU admission

Improving Outcomes for Pregnant Women with T2D

“We have shown that T2D pregnancies are associated with increased risk, both for the mother and for the fetus,” Dr. Scott and colleagues wrote. “The finding that T2D is associated with increased perinatal morbidity and mortality is consistent with its severe metabolic phenotype outside of pregnancy. This may reflect the underlying maternal cardiometabolic status, with increased rates of chronic hypertension in T2D, impacting on placental function and fetal growth.”

The researchers noted that mothers from ethnic minority groups and socioeconomically deprived communities are the ones most often affected by T2D, and socioeconomic deprivation can exacerbate perinatal mortality, widening healthcare disparities.

Dr. Scott and colleagues also addressed strategies for pregnant women with T2D, as follows:

“In developed populations, resources are focused on women with GDM or those at risk of GDM, due to its high prevalence; however, as shown in this meta-analysis, those with T2D have higher rates of congenital anomalies, LGA, perinatal mortality, and stillbirth than those with GDM and control pregnancies. The National Pregnancy in Diabetes Audit 2020 identified glucose control as being the main modifiable risk factor for pregnancy outcomes in T2D. … Continuous glucose monitoring (CGM) is associated with improved glucose control (and therefore pregnancy outcomes) in T1D. Given the severity of pregnancy outcomes in T2D, the use of interventions such as CGM warrant further investigation.”

Further, the increasing prevalence of T2D among women having children indicates that clinicians, researchers, and policymakers must be aware of these higher risks and “work collaboratively with patient groups to optimize pregnancy outcomes and reduce longer term health inequalities for both mothers and their children,” they wrote, noting also that enhanced, supportive care for those with T2D before and during pregnancy “is urgently needed.”