Health management not only during pregnancy but also before and after pregnancy is critical for maternal and neonatal outcomes. For women with pre‑existing diabetes mellitus (PDM), how to implement individualized full‑cycle treatment and management has long been a key clinical focus.
At the 2025 Annual Meeting of the European Association for the Study of Diabetes (EASD), Professor Jennifer Wyckoff and Professor Linda Barbour from the United States, together with Professor Rosa Corcoy Pla from Spain, jointly interpreted the latest guideline developed by the Endocrine Society (ES) and the European Society of Endocrinology (ESE) — the ES/ESE Guideline for the Diagnosis and Management of Pregnant Women with Pre‑existing Diabetes.
This guideline provides evidence‑based recommendations for contraception, pre‑pregnancy preparation, postpartum care, medication selection, and application of new technologies in patients with PDM.
I. Pre-pregnancy and Postpartum: Building a Closed-loop Full-cycle Management
Management of women of reproductive age with diabetes should not be limited to the gestational period, but extended to pre‑pregnancy and postpartum stages to form a complete closed‑loop system.
Recommendation 1
Diabetes patients who may become pregnant should be asked about their pregnancy intention at every reproductive, diabetes, and primary care visit; screening for pregnancy intention is also recommended in emergency departments if conditions permit (conditional recommendation, very low certainty of evidence).
More than half of pregnancies in women with diabetes are unplanned, causing them to miss the optimal window for optimizing glycemic control and overall health. Although direct evidence is limited, substantial indirect evidence shows significant benefits of pre‑conception care (PCC). A meta‑analysis of 36 studies demonstrated that PCC reduces the risk of congenital malformations by 71% and improves multiple outcomes including HbA1c, preterm birth rate, and perinatal mortality.
Recommendation 2
Effective contraception is recommended for diabetes patients with no current pregnancy plan (conditional recommendation, low certainty of evidence).
This recommendation complements pregnancy intention screening. Effective contraception helps ensure women conceive when physically and mentally prepared, thereby significantly reducing the adverse effects of hyperglycemia during fetal organogenesis.
Recommendation 10
For women with pre‑existing diabetes (including those who experienced miscarriage or pregnancy termination), combined endocrine specialist care is recommended in addition to routine postpartum management (conditional recommendation, very low certainty of evidence).
The postpartum period is essentially the “pre‑pregnancy phase” for a potential next pregnancy, yet it is a high‑risk period for fragmented care. Therefore, postpartum endocrine management should focus not only on glycemic control and breastfeeding support but also on long‑term health and future pregnancy needs — planning for lifelong health and preparing for subsequent pregnancies to achieve seamless continuity of care.
II. Controversies and Updates: Selection of Non-insulin Medications
With the increasing use of novel glucose‑lowering agents, their safety during pregnancy has become a major concern. The new guideline provides cautious recommendations.
Recommendation 3
For women with type 2 diabetes (T2DM) planning pregnancy, discontinuation of GLP‑1 RAs is recommended before conception, rather than after pregnancy or in early pregnancy (conditional recommendation, very low certainty of evidence).
This recommendation is mainly based on safety considerations. Abrupt cessation of GLP‑1 RA may lead to rebound hyperglycemia and weight gain, which are highly unfavorable during the critical period of embryonic organogenesis. The guideline adopts a more cautious strategy, recommending early discontinuation and a smooth transition to insulin or other alternatives.
Recommendation 4
Routine add‑on of metformin is not recommended for insulin‑treated patients with pre‑existing diabetes (key update; conditional recommendation, very low certainty of evidence).
Although metformin may reduce the risk of macrosomia, gestational weight gain, and insulin dosage, its potential adverse effects require attention. Randomized controlled studies show that metformin may increase the risk of small‑for‑gestational‑age infants by 42%. Notably, long‑term follow‑up studies suggest that offspring exposed to metformin in utero may have an increased risk of overweight/obesity later in life. Thus, routine use is not recommended, but individualized evaluation may still be considered in specific situations such as limited access to insulin or very high insulin requirements.
III. Technology-enabled Care: Precision Application of CGM and HCL
Advances in glucose monitoring and insulin delivery technologies have introduced new tools for gestational glycemic management, and the guideline defines their appropriate applications.
Recommendation 6
Pregnant women with T2DM may choose either continuous glucose monitoring (CGM) or self‑monitoring of blood glucose (SMBG) (conditional recommendation, very low certainty of evidence).
For patients with T2DM, current evidence does not confirm that CGM is superior to traditional SMBG in improving maternal and neonatal outcomes. Therefore, the guideline provides a conditional “either‑or” recommendation, allowing shared decision‑making between clinicians and patients based on personal preference, lifestyle, device availability, and cost.
Recommendation 7
A single CGM target (TIR 63–140 mg/dL) is not recommended to replace standard fasting (<95 mg/dL, 5.3 mmol/L) and postprandial glucose targets (1‑hour postprandial <140 mg/dL, 7.8 mmol/L; 2‑hour postprandial <120 mg/dL, 6.7 mmol/L) (conditional recommendation, very low certainty of evidence).
This applies to all women with PDM. Fasting and postprandial glucose remain the cornerstone for insulin titration. Focusing solely on 24‑hour time in range (TIR) may overlook fine adjustments for nocturnal and fasting hyperglycemia.
Recommendation 8
Pregnant women with type 1 diabetes (T1DM) are recommended to use a hybrid closed‑loop (HCL) system, rather than insulin pumps with CGM alone or multiple daily injections (MDI) (conditional recommendation, very low certainty of evidence).
Unlike T2DM, HCL systems show clear benefits in pregnant women with T1DM, significantly improving nocturnal glycemic control, increasing nighttime TIR, and reducing time in hypoglycemia (TBR) and hyperglycemia (TAR). Given the importance of stable nocturnal glucose for maternal and fetal health, HCL is recommended for eligible pregnant women with T1DM.
IV. Dietary Management: Avoid Extremes, Seek Balance
Recommendation 5
Women with pre‑existing diabetes during pregnancy may choose either a carbohydrate‑restricted diet (<175 g/day) or a standard diet (≥175 g/day) (conditional recommendation, very low certainty of evidence).
Current evidence does not support an optimal daily carbohydrate intake. Both extremely low and extremely high intake carry potential risks, but either is reasonable within this range and should be determined based on individual conditions.
The release of this joint ES/ESE guideline provides an up‑to‑date evidence‑based framework for the management of pregnant women with pre‑existing diabetes.
Its core highlights include:
Emphasis on the concept of full‑cycle management covering pre‑pregnancy, contraception, and postpartum care
More cautious and explicit recommendations
Strong focus on long‑term safety of mothers and infantsThe guideline embodies the core principles of individualized decision‑making and shared patient‑provider participation.
In the future, with the accumulation of more high‑quality research evidence, we expect these recommendations to be continuously improved to provide stronger protection for maternal and neonatal health.