Impact of Diabetes on Female Fertility
Diabetes significantly impairs female fertility through multiple mechanisms, with women who have diabetes experiencing reduced fertility rates compared to the general population, even before diagnosis in some cases. 1
Types of Diabetes and Fertility Impact
Type 1 Diabetes
- Women with type 1 diabetes have reduced fertility with a standardized fertility ratio of 0.80 (95% CI 0.77-0.82) compared to the general population 2
- Fertility is further reduced in women with diabetes complications:
- Retinopathy: SFR 0.63
- Nephropathy: SFR 0.54
- Neuropathy: SFR 0.50
- Cardiovascular complications: SFR 0.34 2
- Impaired fertility occurs even before type 1 diabetes is diagnosed, with fewer live births before diagnosis than after (IRR 0.58 vs. 0.80) 1
Type 2 Diabetes and CF-Related Diabetes
- CF-related diabetes (CFRD) is associated with subfertility, with 23% of subfertile women with CF having CFRD compared to 16% of women with normal fertility 3
- Women with CFRD are significantly less likely to attempt conception 3
Mechanisms of Reduced Fertility in Diabetic Women
Hormonal and Metabolic Factors
- Insulin/insulin-like growth factor (IGF) pathways act as mediators of human ovarian function 4
- Dysregulation of insulin signaling leads to altered ovulation and fertility 4
- Hyperglycemia coupled with elevated oxidative stress within the female reproductive tract affects sperm storage and utilization 5
Comorbidities Affecting Fertility
- Thyroid disease: Type 1 diabetes combined with hyperthyroidism further reduces fertility (IRR 0.54) 1
- Approximately 5-10% of women with type 1 diabetes have coincident thyroid disorders 3
Complications and Fertility
- Diabetic ketoacidosis is strongly associated with abortion 1
- Higher daily insulin doses correlate with increased abortion rates 1
- Diabetic complications significantly reduce the number of live births 1
Management Strategies to Improve Fertility
Glycemic Control
- Good glycemic control before conception is essential for improving fertility outcomes and reducing pregnancy complications 3
- Target A1C <6.5% (48 mmol/mol) before conception to minimize risks 3, 6
- Women should use effective contraception until glycemic control is optimized 3
Medication Management
- Insulin is the preferred treatment for diabetes during pregnancy 6
- Metformin may be continued in the preconception period for women with type 2 diabetes 3, 7
- ACE inhibitors, ARBs, and statins should be discontinued before attempting conception due to teratogenic risks 3, 6
Screening and Monitoring
- Blood glucose monitoring is essential due to changing insulin requirements 6
- Screening for thyroid disease is recommended in women with type 1 diabetes planning pregnancy 3
- Assessment of renal function and protein excretion should be performed before conception 3
Antioxidant Therapy
- Amelioration of oxidative stress through antioxidant supplementation may enhance fertility in diabetic women 5
Preconception Counseling
- Preconception counseling should be incorporated into routine diabetes care for all women with diabetes starting at puberty 3
- Family planning discussions should include information about:
- Risk of congenital anomalies with poor glycemic control
- Potential for pregnancy complications
- Importance of achieving near-euglycemia before conception 3
Recent Improvements in Fertility Outcomes
- Normalization of fertility has occurred among women with uncomplicated type 1 diabetes diagnosed in the past 20 years 2
- Stricter metabolic control in recent decades may have helped prevent subfertility 2
- Risk of congenital malformations has decreased but remains higher than in the general population 2
Common Pitfalls and Caveats
- Undertreatment of diabetes can lead to subfertility
- Diabetic ketoacidosis can occur at lower blood glucose levels during pregnancy 6
- Insulin requirements change dramatically throughout pregnancy, requiring vigilant monitoring 6
- Women with diabetes may have reduced fertility even before diagnosis, highlighting the importance of blood glucose surveillance in infertile females 1
By addressing these factors through comprehensive diabetes management, women with diabetes can improve their fertility outcomes and reduce the risk of pregnancy complications.