Diabetic pregnancy outcomes in mothers treated with basal insulin lispro protamine suspension or NPH insulin: a multicenter retrospective Italian study

Insulin Use During Gestational and Pre-existing Diabetes in Pregnancy: A Systematic Review of Study Design

INTRODUCTION

Insulin is the first-line pharmacologic therapy for women with diabetes in pregnancy. However, conducting well-designed randomized clinical trials (RCTs) and achieving recommended glycemic targets remains a challenge for this unique population. This systematic literature review (SLR) aimed to understand the evidence for insulin use in pregnancy and the outcome metrics most often used to characterize its effect on glycemic, maternal and fetal outcomes in gestational diabetes mellitus (GDM) and in pregnant women with diabetes.

METHODS

An SLR was conducted using electronic databases in Medline, EMBASE via Ovid platform, evidence-based medicine reviews (2010-2020) and conference proceedings (2018-2019). Studies were included if they assessed the effect of insulin treatment on glycemic, maternal or fetal outcomes in women with diabetes in pregnancy. Studies on any type of diabetes other than gestational or pre-existing diabetes as well as non-human studies were excluded.

RESULTS

In women diagnosed with GDM or pre-existing diabetes, most studies compared treatment of insulin with metformin (n = 35) followed by diet along with lifestyle intervention (n = 24) and glibenclamide (n = 12). Most studies reporting on glycemic outcomes compared insulin with metformin (n = 22) and glibenclamide (n = 4). Fasting blood glucose was the most reported clinical outcome of interest. Among the studies reporting maternal outcomes, method of delivery and delivery complications were most commonly reported. Large for gestational age, stillbirth and perinatal mortality were the most common fetal outcomes reported.

CONCLUSION

This SLR included a total of 108 clinical trials and observational studies with diverse populations and treatment arms. Outcomes varied across the studies, and a lack of consistent outcome measures to manage diabetes in pregnant women was observed. This elucidates a need for global consensus on study design and standardized clinical, maternal and fetal outcomes metrics.

Maternal Diabetes Impairs Insulin and IGF-1 Receptor Expression and Signaling in Human Placenta

BACKGROUND

Maternal high blood glucose during pregnancy increases the risk for both maternal and fetal adverse outcomes. The mechanisms underlying the regulator effects of hyperglycemia on placental development and growth have not been fully illustrated yet. The placenta expresses high amounts of both insulin receptor (IR) and insulin-like growth factor receptor (IGF-1R). It has been reported that the placenta of diabetic women has structural and functional alterations and the insulin/IGF system is likely to play a role in these changes. The aim of the present study was to measure the content of IR and IGF-1R and their phosphorylation in the placenta of women with type 1 diabetes mellitus (T1D) or with gestational diabetes mellitus (GDM) compared to women with normal glucose tolerance (NGT) during pregnancy.

METHODS

Placental tissues were obtained from 80 Caucasian women with a singleton pregnancy. In particular, we collected placenta samples from 20 T1D patients, 20 GDM patients and 40 NGT women during pregnancy. Clinical characteristics and anthropometric measures of all women as well as delivery and newborn characteristics were recorded. Patients were also subdivided on the basis of peripartum glycemia either ≥90 mg/dl or <90 mg/dl, regardless of the diagnosis.

RESULTS

In T1D patients, a higher rate of adverse outcomes was observed. Compared to the GDM women, the T1D group showed significantly higher average capillary blood glucose levels at the third trimester of pregnancy and at peripartum, and higher third-trimester HbA1c values. In both T1D and GDM women, HbA1c values during pregnancy correlated with glucose values in the peripartum period (R-squared 0.14, p=0.02). A positive correlation was observed between phosphorylation of placental IR and the glucose levels during the third trimester of GDM and T1D pregnancy (R-squared 0.21, p=0.003). In the placenta of T1D patients, IGF-1R phosphorylation and IR isoform A (IR-A) expression were significantly increased (p=0.006 and p=0.040, respectively), compared to the NGT women. Moreover, IGF-1R phosphorylation was significantly increased (p<0.0001) in the placenta of patients with peripartum glucose >90 mg/dl, while IR-A expression was increased in those with peripartum blood glucose higher than 120 mg/dl (p=0.046).

CONCLUSIONS

To the best of our knowledge, our study represents the first one in which an increased maternal blood glucose level during pregnancy is associated with an increased IGF-1R phosphorylation and IR-A expression in the placenta. Both these mechanisms can promote an excessive fetal growth.

Effect of Elevated Ketone Body on Maternal and Infant Outcome of Pregnant Women with Abnormal Glucose Metabolism During Pregnancy

Ketone bodies are one of the products of fat metabolism which can be used as an alternative energy source for the human body in states of glucose deficiency. Normal pregnant women may develop ketosis due to physiological changes during pregnancy, while pregnant women with abnormal glucose metabolism are more likely to develop ketosis due to abnormal insulin secretion. Animal experiments and clinical studies have shown that exposure to high-ketone environments during pregnancy is closely related to adverse maternal and infant outcomes. However, there is no unified conclusion on whether ketone bodies should be routinely monitored during pregnancy. This review summarizes the existing studies on ketone body levels and pregnancy outcomes in the case of abnormal blood glucose during pregnancy, elaborates the current guidelines on the level of ketone bodies, provides the detection and treatment of ketosis in pregnant women with abnormal blood glucose in the clinical practice.

Advances in pharmacological treatment of type 1 diabetes during pregnancy

INTRODUCTION

In women with type 1 diabetes mellitus (T1DM), pregnancy is associated with a potential risk of maternal, foetal and neonatal outcomes. Stringent metabolic control is required to improve these outcomes.

AREAS COVERED

In this review, the authors summarise the current evidence from studies on the pharmacological therapy and on monitoring of T1DM during pregnancy. The authors also discuss the use of new technologies to improve therapeutic management and patient compliance.

EXPERT OPINION

Pre-conception counselling is essential in T1DM to minimise pregnancy risks. Pregnancy in T1DM is always considered a high-risk pregnancy. During pregnancy, the target haemoglobin A1C (HbA_1c) is near-normal at <6%, without excessive hypoglycaemia. Strict control of pre- and post-prandial glucose is also required. Human soluble insulin, neutral protamine Hagedorn and the quick-acting insulin analogues aspart and lispro are widely used. Insulin is administered either as a basal-bolus regimen or by continuous subcutaneous insulin infusion. Careful and strict glucose monitoring is also needed during labour and delivery, including caesarean section. Moreover, the control of retinopathy, hypertension, nephropathy, hyper- and hypothyroidism is required. Post-partum, insulin requirements decrease, and less stringent glycaemic control is pursued, to avoid hypoglycaemias. Finally, breastfeeding is recommended and should be encouraged.

Effectiveness of Insulin Analogs Compared with Human Insulins in Pregnant Women with Diabetes Mellitus: Systematic Review and Meta-analysis

Diabetes during pregnancy has been linked to unfavorable maternal-fetal outcomes. Human insulins are the first drug of choice because of the proven safety in their use. However, there are still questions about the use of insulin analogs during pregnancy. The objective of the present study was to determine the effectiveness of insulin analogs compared with human insulin in the treatment of pregnant women with diabetes through a systematic review with meta-analysis. The search comprised the period since the inception of each database until July 2017, and the following databases were used: MEDLINE, CINAHL, EMBASE, ISI Web of Science, LILACS, Scopus, SIGLE and Google Scholar. We have selected 29 original articles: 11 were randomized clinical trials and 18 were observational studies. We have explored data from 6,382 participants. All of the articles were classified as having an intermediate to high risk of bias. The variable that showed favorable results for the use of insulin analogs was gestational age, with a mean difference of - 0.26 (95 % confidence interval [CI]: 0.03-0.49; p = 0.02), but with significant heterogeneity (Higgins test [I2] = 38%; chi-squared test [χ2] = 16.24; degree of freedom [DF] = 10; p = 0.09). This result, in the clinical practice, does not compromise the fetal well-being, since all babies were born at term. There was publication bias in the gestational age and neonatal weight variables. To date, the evidence analyzed has a moderate-to-high risk of bias and does not allow the conclusion that insulin analogs are more effective when compared with human insulin to treat diabetic pregnant women.

Glucose Targets and Insulin Choice in Pregnancy: What Has Changed in the Last Decade?

PURPOSE OF REVIEW

To review current glycaemic targets and the potential use of newer insulin formulations in pregnancy.

RECENT FINDINGS

The impact of stricter glycaemic control on perinatal outcomes remains controversial, showing conflicting results. Current ongoing randomised trials investigating the role of tighter glucose targets in pregnancy should help clarify the benefit of tighter glucose control. Optimal timing for self-monitoring blood glucose (SMBG) remains debatable. Data suggest that post-prandial SMBG, particularly at 1 h, offers the best prediction of adverse perinatal outcome. To achieve these targets, insulin is the standard therapy. Novel insulin formulations offer benefits outside of pregnancy. Recent data on the use of new insulins in pregnancy (e.g. insulin degludec and glargine (U 300)) is limited to case reports. Glycaemic targets have remained unchanged in the last decade. Studies using stricter glycaemic targets may improve perinatal outcomes. Newer insulin formulations may offer increased flexibility and glycaemic control. Clinicians caring for women with diabetes striving to minimise adverse perinatal outcomes will find this review of interest.

Maternal-Fetal Outcomes in 34 Pregnant Women with Type 1 Diabetes in Sensor-Augmented Insulin Pump Therapy

BACKGROUND

Pregnancy in women with type 1 diabetes (T1D) is associated with increased risk of maternal complications and neonatal morbidity and mortality. Optimizing glycemic control improves these outcomes.

OBJECTIVE

To describe the experience of using sensor-augmented insulin pump therapy (SAPT) and SAPT + low-glucose suspension (LGS) on pregnant women with T1D, including neonatal and maternal outcomes.

METHODS

A prospective observational study was conducted in women with T1D who started SAPT and SAPT + LGS before or during pregnancy at the San Ignacio University Hospital Diabetes Center in Bogotá, Colombia. The main indication was severe hypoglycemia (SH) and poor glycemic control. Glycated hemoglobin (A1c), hypoglycemia, and maternal and fetal outcomes were assessed.

RESULTS

Thirty-four pregnant women with T1D on SAPT and SAPT + LGS were included. Sixteen patients started therapy during pregnancy at a mean gestational age of 17.6 ± 8.3 weeks. Mean preconceptional A1c was 8.24% ± 2.02%. Absolute reduction of A1c level from prepregnancy to third trimester was -1.63% (P < 0.0001), with a significant clinical and statistical reduction in both groups, women who initiated SAPT before or during pregnancy. 52.9% of patients in second trimester and 66.6% in third trimester achieved A1c <6.5%, respectively. 91.1% underwent cesarean section. The main reasons were iterative cesarean (30%), fetal distress (20%), and preeclampsia (16%). The median gestational age at delivery was 37 weeks and 15 pregnancies resulted in preterm delivery. There was neither maternal-fetal mortality nor severe hypoglycemic episodes. Two patients had diabetic ketoacidosis.

CONCLUSIONS

In pregnant patients with T1D and high risk of hypoglycemia, SAPT and SAPT + LGS should be considered as a therapeutic alternative for A1c reduction with a low risk of SH. However, additional studies are required to evaluate the efficacy and safety of this therapy during pregnancy.

Use of Insulin Lispro Protamine Suspension in Pregnancy

Maternal metabolism changes substantially during pregnancy, which poses numerous challenges to physicians managing pregnancy in women with diabetes. Insulin is the agent of choice for glycemic control in pregnant women with diabetes, and the insulin analogs are particularly interesting for use in pregnancy. These agents may reduce the risk of hypoglycemia and promote a more physiological glycemic profile than regular human insulin in pregnant women with type 1 (T1D), type 2 (T2D), or gestational (GDM) diabetes. However, there have been concerns regarding potential risk for crossing the placental barrier, mitogenic stimulation, teratogenicity, and embryotoxicity. Insulin lispro protamine suspension (ILPS), an intermediate- to long-acting insulin, has a stable and predictable pharmacological profile, and appears to have a favorable time–action profile and produce desirable basal and postprandial glycemic control. As the binding of insulin lispro is unaffected by the protamine molecule, ILPS is likely to have the same mitogenic and immunogenic potential as insulin lispro. Insulin lispro produces similar outcomes to regular insulin in pregnant women with T1D, T2D, or GDM, does not cross the placental barrier, and is considered a useful treatment option for pregnant women with diabetes. Clinical data support the usefulness of ILPS for basal insulin coverage in non-pregnant patients with T1D or T2D, and suggest that the optimal regimen, in terms of balance between efficacy and hypoglycemic risk, is a once-daily injection, especially in patients with T2D. Available data concerning use of ILPS in pregnant women are currently derived from retrospective analyses that involved, in total, >1200 pregnant women. These analyses suggest that ILPS is at least as safe and effective as neutral protamine Hagedorn insulin. Thus, available experimental and clinical data suggest that ILPS once daily is a safe and effective option for the management of diabetes in pregnant women.

Funding: Eli Lilly and Company.