Pregnancy Loss Increases Risk of Type 2 Diabetes
MAY 21, 2020
Pia Egerup, MD
Pia Egerup, MD, and a team of Denmark-based investigators used a Danish nationwide data cohort of women born from 1957-1997. They found a significant and consistent association between pregnancy loss and later type 2 diabetes increased with more losses.
The investigators identified all women born from 1957-1977 with a diagnosis of type 2 diabetes during 1977-2017. Every woman with diabetes (case population) was matched by birth year and educational level to 10 control women without diabetes in the general Danish population.
A diagnosis of type 2 diabetes was defined based on an algorithm for chronic diseases published by The Danish Health Data Authority. Age at diagnosis was determined as the first hospital contact with a discharge diagnosis or a first filled prescription of glucose-lowering drugs.
The team calculated the odds of developing type 2 diabetes with different numbers of pregnancy losses. Each pregnancy loss was categorized as the total number of pregnancy losses before the index date: 0, 1, 2, or >3 losses. The investigators further divided the women with 0 pregnancy losses into those who achieved a pregnancy (live birth, stillbirth, molar pregnancy, ectopic pregnancy, or induced abortion) and those who never achieved a pregnancy.
Overall, Egerup and the team included 24,774 women diagnosed with type 2 diabetes in the case population. After matching, the control population included 247,740 women without type 2 diabetes. The age at index and education level were similar in both groups, which indicated similar matching.
A significant number of women in the case group had a history of gestational diabetes, family history diabetes, cardiovascular disease, obesity, and hypertension. Among the population, 74.5% of the cases and 78.7% of the controls never experienced a pregnancy loss.
Those with 1, 2, and >3 pregnancy losses made up 19.1%, 4.3%, and 2.1% of the cases and 16.8%, 3.2%, and 1.3% of the controls. Women with 1, 2, and >3 pregnancy losses had ORs of type 2 diabetes of 1.18 (95% CI, 1.13-1.23), 1.38 (95% CI, 1.27-1.49), and 1.71 (95% CI, 1.53-1.92) compared with those with no losses. More women in the case group (31.7%) never achieved pregnancy compared to 25.1% in the controls.
The investigators included 3064 cases and 42,276 controls in a subgroup analysis. The team adjusted for obesity and found women with 1, 2, and >3 pregnancy losses had significantly increased ORs for type 2 diabetes of 1.4 (95% CI, 1.25-1.58), 1.71 (95% CI, 1.35-2.17) and 2.79 (95% CI, 1.98-3.94) compared with women who have never had a pregnancy loss. After adjustment for gestational diabetes, women with 1, 2, and >3 pregnancy losses had an OR for type 2 diabetes of 1.14 (95%CI, 1.1-1.19), 1.32 (95% CI, 1.21-1.43) and 1.53 (95% CI, 1.36-1.73).
Egerup and the team found overall adverse outcomes in reproductive history were linked with a higher risk of type 2 diabetes later in life. The association could be due to shared immunological and/or metabolic components, the study authors said.
Women who have had >3 pregnancy losses could monitor their blood sugar level more frequently so they can get advice to lower their risk or participate in interventions early if diabetes developed, they suggested. Additional research could explore whether the association was common due to background factors or prediabetic metabolic conditions.
The study, “Pregnancy loss is associated with type 2 diabetes: a nationwide case-control study,” was published online in the journal Diabetologia.