Type 1 diabetes impairs female fertility even before it is diagnosed

Effects of high-normal fasting blood glucose on ART outcomes of frozen-thawed single blastocyst transfer in women with normal BMI

PURPOSE

This retrospective cohort study aims to investigate whether high-normal fasting blood glucose (FBG) affects assisted reproductive technology (ART) outcomes undergoing single blastocyst frozen-thawed embryo transfer (FET) cycles in women with normal body mass index (BMI).

METHODS

944 women with normal BMI and FBG levels undergoing single blastocyst FET cycles were enrolled. Based on the median of FBG (4.97 mmol/L, 1 mmol/L = 18 mg/dL), the subjects were categorized into the low-normal group (3.90 ≤ FBG ≤ 4.97 mmol/L, n = 472) and the high-normal group (4.97 < FBG < 6.10 mmol/L, n = 472). Multivariable logistic regression and receiver operating characteristic (ROC) were used to analyze the relationship between high-normal FBG and ART outcomes.

PRIMARY OUTCOME

live birth rate (LBR).

RESULTS

LBR was significantly lower in the high-normal group than in the low-normal group (36.8% vs. 45.1%, p = 0.010), and the miscarriage rate was considerably higher than that in the low-normal group (23.9% vs. 16.5%, p = 0.041). High-normal FBG of female was an independent predictor of live birth (adjusted OR:0.747, 95% CI: 0.541-0.963, p = 0.027) and miscarriage (adjusted OR:1.610, 95% CI: 1.018-2.547, p = 0.042). ROC analyses showed that the cut-off values of FBG (endpoints: live birth and miscarriage) were 5.07 mmol/L, and 5.01 mmol/L, respectively.

CONCLUSIONS

In women with normal BMI, high-normal FBG is an independent risk factor for lower LBR and higher miscarriage rate in single blastocyst FET cycles. Attention to preconception FBG monitoring in this particular population may allow early intervention to improve ART outcomes.

Association of diabetes mellitus with risk of reproductive impairment in females: A comprehensive review

Reproductive impairment is the most prevalent yet most ignored complication of diabetes mellitus. In diabetes, the problem associated with reproductive health is comprehensive in both males and females. Diabetic females have problems like delayed menarche, irregular menstrual cycle, subfertility, complications in pregnancy and early menopause. This may decrease reproductive age in diabetic females as the menarche is delayed and menopause is early in them. Like diabetic males, diabetic females also have the negative effect of oxidative stress on the reproductive system. This may lead to dysfunction of the ovary. It affects the physiological cycle like the ovary's maturation, embryo development and pregnancy. These complications also affect the offspring, and they may also become diabetic. This review aims to concentrate on the effect of diabetes on the reproductive system of females and the impairment caused by it. We will also discuss in detail the role of the hypothalamus-pituitary ovary axis, diabetes impact on different reproductive phases of females, and the sexual disorders that occur in them.

Gonadal dysfunction in women with diabetes mellitus

It is well known that both type 1 and type 2 diabetes mellitus (DM) are related to increased risk for cardiovascular (CV) and chronic kidney disease (CKD). However, besides these prominently presented complications, DM has also been associated with reproductive dysfunctions. It seems that these disorders are met in up to 40% of women with DM and consist of delayed menarche, all types of menstrual disorders, such as amenorrhea, oligomenorrhea, menstrual irregularity, as well as menorrhagia, infertility, characteristics of polycystic ovary syndrome (PCOS) and early (or rarely late) menopause. In type 1 DM (T1DM), insulin treatment, although it has reduced the rates of insulinopenic-induced hypogonadotropic hypogonadism, an entity commonly presented in many women with the disease in the past decades, when it is used in excess it can also promote hyperandrogenism. Regarding type 2 DM (T2DM), insulin resistance (IR) and hyperinsulinemia have mainly been implicated in the pathogenesis of reproductive dysfunctions, as insulin can act as gonadotropin on the theca cells of the ovary and can lead to hyperandrogenism and inhibition of proper ovulation. This review aims to detail the reproductive dysfunctions associated with DM and provide scientific data to enlighten the underlying pathogenetic mechanisms.

Embryos from Prepubertal Hyperglycemic Female Mice Respond Differentially to Oxygen Tension In Vitro

Reduced oxygen during embryo culture in human ART prevents embryo oxidative stress. Oxidative stress is also the major mechanism by which maternal diabetes impairs embryonic development. This study employed induced hyperglycemia prepubertal mice to mimic childhood diabetes to understand the effects of varying oxygen tension during in vitro embryonic development. The oocytes were fertilized and cultured at low (≈5%) oxygen (LOT) or atmospheric (≈20%) oxygen tension (HOT) for up to 96 h. Embryo development, apoptosis in blastocysts, inner cell mass (ICM) outgrowth proliferation, and Hif1α expression were assessed. Though the oocyte quality and meiotic spindle were not affected, the fertilization rate (94.86 ± 1.18 vs. 85.17 ± 2.81), blastocyst rate (80.92 ± 2.92 vs. 69.32 ± 2.54), and ICM proliferation ability (51.04 ± 9.22 vs. 17.08 ± 3.05) of the hyperglycemic embryos were significantly higher in the LOT compared to the HOT group. On the other hand, blastocysts from the hyperglycemic group, cultured at HOT, had a 1.5-fold increase in apoptotic cells compared to the control and lower Hif1α transcripts in ICM outgrowths compared to the LOT. Increased susceptibility of embryos from hyperglycemic mice to higher oxygen tension warrants the need to individualize the conditions for embryo culture systems in ART clinics, particularly when an endogenous maternal pathology affects the ovarian environment.

Differential Effect of 2 Hormonal Contraceptives on the Relative Telomere Length of Youth With Type 1 Diabetes

Context

Adolescents and young women (AYA) with type 1 diabetes (T1D) may require hormonal contraception for an extended period. However, it is unclear what effect hormonal contraception has on telomere length, a marker of the risk for complications.

Objective

To investigate the relative telomere length (RTL) in AYA with T1D (AYA-T1D) and healthy young women (AYA-C) after 18 months of combined oral contraception use (COC) with ethinyl estradiol/desogestrel, or a subdermal etonogestrel implant (IM).

Methods

A nonrandomized prospective study was performed in which 39 AYA-T1D and 40 AYA-C chose the COC or the IM. RTL was measured by monochrome multiplex-quantitative PCR in DNA from peripheral blood mononuclear cells (PBMC). The impact of contraceptives and clinical variables on RTL was assessed using lineal regression analysis.

Results

Longer RTL compared to baseline was observed in AYA-T1D (P < .05) and AYA-C (P  < .01) after using the IM. However, the total of AYA and the AYA-C group treated with COC decreased RTL after 18 months of treatment compared to baseline (P < .05). The type of contraceptive used was determinant for the changes in RTL compared to baseline in all subjects and controls (P ≤ .006). For AYA-T1D, HbA1c levels were not associated with RTL, but the high-sensitivity C-reactive protein was negatively related with the changes in RTL at 18 months compared to baseline (standardized R2 : 0.230, P  = .003).

Conclusion

IM was associated with longer RTL in AYA-T1D and AYA-C. In contrast, a shortening of telomere length in PBMC was observed after using COC.

Altered sperm fate in the reproductive tract milieu due to oxidative stress leads to sub-fertility in type 1 diabetes females: A Drosophila-based study

AIMS

Female sub-fertility, a prominent complication due to Type 1 diabetes (T1D), is generally attributed to disturbances in menstrual cycles and/or ovarian defects/disorders. T1D women, however, are high in oxidative stress, although the impact of the same on their reproduction and associated events remains unknown. Therefore, we assessed the repercussions of elevated oxidative stress on the sperm fate (storage/utilization) in the reproductive tract milieu of T1D females and their fertility using the Drosophila T1D model (Df[dilp1-5]), which lacks insulin-like peptides and displays reduced female fertility.

MAIN METHODS

We mated Df[dilp1-5] females to normal males and thereafter examined sperm storage and/or utilization in conjunction with oxidative stress parameters in mated Df[dilp1-5] females at different time points. Also, the impact of antioxidant (Amla or Vitamin C) supplementation on the above oxidative stress parameters in Df[dilp1-5] females and the consequences on their sperm and fertility levels were examined.

KEY FINDINGS

Df[dilp1-5] females showed elevated oxidative stress parameters and a few of their reproductive tract proteins are oxidatively modified. Also, these females stored significantly fewer sperm and also did not utilize sperm as efficiently as their controls. Surprisingly, amelioration of the oxidative stress in Df[dilp1-5] females' milieu through antioxidant (Amla or vitamin C) supplementation enhanced sperm storage and improved fertility.

SIGNIFICANCE

Hyperglycemia coupled with elevated oxidative stress within the female reproductive tract environment affects the sperm fate, thereby reducing female fertility in T1D. In addition, these findings suggest that antioxidant supplementation may substantially aid in the mitigation of sub-fertility in T1D females.

Intrauterine hyperglycemia impairs endometrial receptivity via up-regulating SGK1 in diabetes

Diabetes is a complex metabolic disorder which can adversely affect reproductive function. SGK1 is found to be up-regulated in multiple tissues of diabetic patients. However, the effects of diabetes on endometrial SGK1 expression and endometrial receptivity remain unknown. In this study, we established a streptozotocin-induced diabetic mouse model and observed reduced implantation sites, retarded development of pinopodes, increased SGK1, and aberrant expression of LIF and MUC1 in the endometrial epithelium. We injected the uterine lumen of normal mice with high-glucose solution and cultured endometrial cells in high-glucose medium to mimic intrauterine hyperglycemia. Both studies provided compelling evidence that hyperglycemia could lead to diminished embryo implantation and dysregulated SGK1, LIF and MUC1. Additionally, through over-expression of SGK1 in vivo and in vitro, we found that enhanced SGK1 also decreased LIF expression, increased MUC1 expression, and attenuated embryo implantation rate. We further identified that hyperglycemia-activated SMAD2/3 might be responsible for the enhancement of SGK1 and verified directly the interaction between SMAD3 and corresponding SMAD binding elements within SGK1 promoter. Taken together, our study confirmed the association between diabetes-related hyperglycemia and endometrial receptivity defects. Hyperglycemia-induced SGK1 has a tremendous role in this pathological process, rendering it as an attractive therapeutic target for diabetes-related reproductive disorders.

Prenatal monitoring of pregnancies complicated by diabetes mellitus

Preconception and prenatal monitoring evaluate the condition of the mother's underlying disease and possible complications during pregnancy. Before conception, patients with diabetes should be informed that suboptimal glycoregulation is associated with reduced fertility and pregnancy losses. The task of the perinatologist in pregnancies affected by diabetes mellitus is to prevent complications of the underlying disease, such as hypoglycemic crises. Another important component of prenatal care in diabetic pregnancies is the recognition and prevention of pregnancy complications such as preeclampsia, polyhydramnios, congenital malformations, fetal macrosomia, and infections.

The Kind of Conception Affects the Kind of Cesarean Delivery in Primiparous Women

BACKGROUND

So far, multiple factors have been found to be related to the IVF procedure, the most prevalent being extremes of maternal age, infections, previous gynecological history, infertility and others. Although women achieve the coveted pregnancy with the development of IVF technology, the rapid increase contributes to the increase of primary cesarean sections rates.

OBJECTIVE

The aim of the study was to identify if the kind of conception affects the kind of cesarean delivery among primiparous women in Greece.

METHODS

This cross-sectional observational study took place from September 2019 to February 2020 at the University Hospital of Larisa in Greece. One hundred and sixty-two primiparous women who underwent a cesarean section (c-section) after IVF (n=27) and natural conception (n=135) participated in the study.

RESULTS

The mean age of the IVF and natural conception groups were 36.22 and 31.08 years, respectively. Nineteen (70.4%) women of the IVF group had a previous medical or gynecological history in contrast to 48 (35.6%) women of the natural conception group. Only 55.6% of the IVF group had a full-term pregnancy unlike 88.1% of women in the natural conception group. An elective c-section was performed in 18 (66.7%) of the women who conceived after IVF, as opposed to 45 (33.3%) of the women who conceived naturally.

CONCLUSION

This cross-sectional study showed that IVF conception was associated with high rates of elective cesarean section as opposed to women with natural conception. The causes of c-sections must be evidence based because the primary cesarean delivery is a major factor contributing to increased c-section rates.

What factors determine the pregnancy outcome in patients with essential thrombocythemia?

Objectives: Treatment of essential thrombocythemia (ET) is particularly challenging in pregnancy due to the increased risk of thromboembolic complications. Therefore, the use of antithrombotic regimens are recommended in pregnant women with ET.Methods: The study included 52 pregnancies in 27 patients diagnosed with ET, who were treated in Department of Haematology. The influence of anticoagulant, antiplatelet and cytoreductive therapy on the course and outcome of pregnancy was analysed. This study also examined if there was any correlation between molecular and clinical features such as mutational profile, blood count, presence of acquired von Willebrand syndrome (AvWS), the International Prognostic Score for Essential Thrombocythemia (IPSET) risk group and the IPSET-thrombosis risk group and pregnancy outcome.Results: Study participants who received antithrombotic therapy were significantly more likely to give birth to a healthy child. The best outcomes were observed in patients who received low dose acetylsalicylic acid (ASA) together with low-molecular-weight heparin (LMWH). There was a statistically significant correlation between classification to the high-risk group according to the IPSET-thrombosis score and incidence of miscarriage. Cytoreductive treatment with interferon-α2, as well as the presence of AvWS did not increase the likelihood of pregnancy loss. Blood counts and presence of specific gene mutations profile were also not found to be significant determinants of pregnancy outcome.Conclusion: To our best knowledge, this is the first clinical study investigating the correlation between risk group (according to IPSET and IPSET-thrombosis) and pregnancy outcome in women with ET.

Metformin mitigates impaired testicular lactate transport/utilisation and improves sexual behaviour in streptozotocin-induced diabetic rats

CONTEXT

Lactate is the preferred energy substrate for developing testicular germ cells. Diabetes is associated with impaired testicular lactate transport/utilisation, and poor sexual behaviour.

OBJECTIVE

To examine the effects of metformin on parameters involved in testicular lactate production, transport/utilisation, and sexual behaviour in diabetic state.

METHODS

Male Sprague-Dawley rats were assigned into normal control (NC), diabetic control (DC), and metformin-treated diabetic group (n = 6/group). Metformin (300 mg/kg b.w./day) was administrated orally for 4 weeks.

RESULTS

Intra-testicular glucose and lactate levels, and lactate dehydrogenase (LDH) activity increased, while the mRNA transcript levels of genes responsible for testicular glucose and lactate transport/utilisation (glucose transporter 3, monocarboxylate transporter 4 (MCT4), MCT2, and LDH type C) decreased in DC group. Furthermore, penile nitric oxide increased, while cyclic guanosine monophosphate decreased, with impaired sexual behaviour in DC group. Treatment with metformin improved these parameters.

CONCLUSIONS

Metformin increases testicular lactate transport/utilisation and improves sexual behaviour in diabetic state.

The Increasing Possibility of Pregnancy Postbariatric Surgery: a Comprehensive National Cohort Study in Asian Population

PURPOSE

The present study aimed to investigate bariatric surgery's effects on pregnancy in obese women.

MATERIALS AND METHODS

The source of the data was the Taiwan National Health Insurance Research Database. We extracted female patients aged 18 to 45 years who had been diagnosed with obesity from 2005 to 2010. Two groups were formed based on bariatric surgery, according to the medical procedure codes of ICD-9-2001. The propensity score match of 1:1 was coordinated, based on the age, previous delivery, and the existence of comorbidities in patients. The primary endpoint was regarded as a pregnancy, including abortion, ectopic pregnancy, and delivery. The follow-up was performed until the end of 2013, or death.

RESULTS

There were 689 patients placed in each group, with a median of 64.8 follow-up months. Following multivariate analysis of the data, bariatric surgery resulted in significantly higher chances for pregnancy (aHR 2.886, p < 0.001) and resulted in a higher chance of successful delivery (aHR 2.775, p < 0.001) and vaginal delivery (aHR = 6.426, p < 0.001) compared with NS group. Moreover, we identified BS has a significantly higher proportion of vaginal delivery (BS 44.74% vs. NS 20%, p = 0.025) with significantly lower overall complications during labor (BS 9.21% vs. NS 33.3%, p = 0.006).

CONCLUSION

Patients suffering from obesity who undergo bariatric surgery have higher chances of pregnancy, successful delivery, vaginal delivery, and lower maternal complications during labor. Bariatric surgery did increase the possibility of pregnancy in obese patients.

Maternal near miss and potentially life-threatening condition determinants in patients with type 1 diabetes mellitus at a university hospital in São Paulo, Brazil: a retrospective study

BACKGROUND

To date, the rates of potentially life-threatening condition (PTLC), maternal near miss (MNM) and maternal deaths in pregnant patients with type 1 diabetes mellitus (T1DM) and variables associated to it have not been studied.

METHODS

This study was as a cross-sectional retrospective study conducted at São Paulo Hospital of Universidade Federal de São Paulo, a tertiary hospital that provides public medical care through the Brazilian unified health system to high-risk pregnancies. Inclusion criteria were T1DM pregnant women who delivered from January 2005 to December 2015. Three groups were established by the World Heath Organization criteria and associations were assessed using the chi-square test in between MNM and no morbidity or PLTC and no morbidity. A P value < 0.05 was considered statistically significant.

RESULTS

The final sample included 137 patients, 8 MNM cases (5.84%), 51 PLTC (37.23%), no cases of maternal deaths and 78 patients (56.93%) did not present any complication. Moreover, there were 122 live births, resulting in a near miss rate of 65.5 per 1.000 live births in patients with T1DM. Two of the MNM cases were for clinical criteria (uncontrollable fit in both) and laboratory criteria for the other six: one patient with severe acute azotemia (creatinine > 300 μmol/ml), one patient with severe hypoperfusion (lactate > 5 mmol/L) and four of them with loss of consciousness and the presence of glucose and ketoacids in urine. PLTC criteria were studied in MNM and PLTC cases. Prolonged hospital stay was the most prevalent PLTC criteria in both groups (100% of MNM cases and 96% of PLTC), followed by renal failure in 50% of MNM cases and severe preeclampsia in 22% of PLTC cases. This study could not find any association between prenatal factors or sociodemographic characteristics with maternal morbidity.

CONCLUSIONS

MNM rate in T1DM was extremely high, and determined by complications of the primary disease or hypertensive disorders. No sociodemographic variables studied were related to maternal morbidity; therefore, we could not predict what increases MNM and PLTC in this specific population.

Potential causes of male and female infertility in Qatar

A steady decline in the fertility rate has been observed in Qatar during the past fifty years. Therefore, infertility is considered a national priority in Qatar, a pronatalist society. This review article summarises the potential causes of infertility that are particularly prevalent in the Qatari population. The high rate of consanguinity leading to genetic abnormalities, the high incidence of metabolic disease, environmental contamination due to the rapid urbanization and oil and natural gas extraction procedures are discussed. In addition, the particular lifestyle of the Qatari population and the influence of religion and culture on sexual and reproductive behavior in an Arab/Islamic society are considered. The active response of the state of Qatar in implementing ways to mitigate the effects of these factors to protect fertility are also presented.

Diabetes: a metabolic and reproductive disorder in women

Reproductive dysfunction is a common but little studied complication of diabetes. The spectrum of reproductive health problems in diabetes is broad, and encompasses delayed puberty and menarche, menstrual cycle abnormalities, subfertility, adverse pregnancy outcomes, and potentially early menopause. Depending on the age at diagnosis of diabetes, reproductive problems can manifest early on in puberty, emerge later when fertility is desired, or occur during the climacteric period. Historically, women with type 1 diabetes have frequently had amenorrhoea and infertility, due to central hypogonadism. With the intensification of insulin therapy and improved metabolic control, these problems have declined, but do persist. Additional reproductive implications of contemporary diabetes management are now emerging, including polycystic ovary syndrome and hyperandrogenism, which are underpinned by insulin action on the ovary. The sharp rise in type 2 diabetes incidence in youth suggests that more women of reproductive age will encounter diabetes-related reproductive problems in their lifetimes. With an ever increasing number of young women living with diabetes, clinicians need to be aware of and equipped for the challenges of navigating reproductive health concerns across the lifespan.

Evaluation of Diabetes Effects on the Expression of Leukemia Inhibitory Factor and Vascular Endothelial Growth Factor A Genes and Proteins at the Time of Endometrial Receptivity after Superovulation in Rat Model

Background:

Diabetes, a major metabolic disorder, seems to affect the fertility rates of women in various ways. Due to the uncertainty of the effects of diabetes along with superovulation treatment on the infertility, we investigate the effects of ovulation induction treatment as therapeutic approach on the expression of leukemia inhibitory factor (LIF) and vascular endothelial growth factor A (VEGFA) as two main factors which are involved in the implantation in the streptozotocin (STZ)-induced type 1 diabetic rats.

Materials and Methods:

Type 1 diabetes was induced by injections of STZ in Wistar rats. The animals were kept in diabetic conditions for 4 weeks, while some were treated with insulin for treatment. After treatment, the ovulation was induced by human menopausal gonadotropin (hMG) and human chorionic gonadotropin (hCG). The rats were then sacrificed and the expression of LIF and VEGFA was checked by immunohistochemistry staining method, and the relative expression of LIF and VEGFA was measured by quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blotting methods.

Results:

It was observed that diabetes and insulin treatment for diabetes altered the expression of Lif and VEGFA in both mRNA and protein levels. However, superovulation treatment seems to ameliorate this alternation for both factors.

Conclusion:

According to our results, diabetes and insulin therapy could alter the expression of Lif and VEGFA genes and proteins that are effective in endometrial receptivity and implantation process. It seems in diabetic cases, the effect of hCG and hMG therapy by itself could regulate the level of expression and presence of these two genes and proteins.

Water Soluble Vitamins and their Role in Diabetes and its Complications

BACKGROUND

Diabetes is a metabolic disorder associated with abnormally high levels of glucose in the blood due to inadequate production of insulin or inadequate sensitivity of cells to the action of insulin. Diabetes has become an increasing challenge in the world. The predicted diabetic population according to the World Health Organization is 8.7% between the age group 20-70 years. There are many complications linked to prolonged high blood glucose levels, such as microvascular complications and macrovascular complications. Vitamins play an important role in glucose metabolism and the potential utility of supplementation is relevant for the prevention and/or management of diabetes mellitus and its complications.

METHODS

Literature search was performed using various dataset like PUBMED, EBSCO, ProQuest, Scopus and selected websites like the National Institute of Health and the World Health Organization.

RESULT

Water-soluble vitamins have been thoroughly studied for their activity in diabetes and diabetic complications.

CONCLUSION

Water-soluble vitamins like B1, B3, B6, B7, B9 and B12 have notable effects in diabetes mellitus and its related complications like nephropathy, neuropathy, retinopathy and cardiomyopathy.

Type 1 Diabetes in Pregnancy

Congenital malformations and perinatal mortality rates remain severalfold higher in pregnant women with type 1 diabetes than in the background population, and still only a minority of women plan their pregnancy. Optimizing glycemic control is the accepted goal, but remains challenging, and must be constantly balanced against the risks of hypoglycemia. Recent advances including Continuous Glucose Monitoring Systems, Continuous Subcutaneous Insulin Infusion, Closed Loop Devices and very Fast Acting Insulin Aspart analogs offer new possibilities to increase glucose time in target in selected, motivated patients, however their relative roles and indication for use require further elucidation. The importance of education cannot be overstated.

Real-World Experience of Adding Metformin in Pregnant Women with Type 1 Diabetes in a Chinese Population: A Retrospective Cohort

INTRODUCTION

Glycemic control in pregnant women with type 1 diabetes (T1D) is challenging with only insulin, and the incidence rate of adverse perinatal outcomes is high. Increasing data have indicated the safety and effect of metformin in pregnancy; however, no relevant data are available in pregnant women with T1D. We aimed to investigate glycemic control and perinatal outcomes in pregnant women with T1D in a Chinese population and explored the role of metformin in these patients.

METHODS

We obtained data of 38 pregnant women with T1D who received regular antenatal care and delivered at Peking Union Medical College Hospital (PUMCH) between 1 January 2006 and 31 May 2018. The perinatal outcomes of T1D patients who added metformin as adjunct treatment and those who remained on insulin-alone therapy were compared retrospectively.

RESULTS

Being overweight was common (35.1%) in pregnant women with T1D. On average, the insulin dose increased by 35.30 ± 22.60 unit/day during pregnancy. The cesarean delivery rate was high (65.8%), and fetal macrosomia was the main reason. The change of HbA1c in the metformin-insulin group was more prominent than in the insulin-only group (- 1.47 ± 1.17% vs. - 0.90 ± 1.13%, p = 0.05). There was no statistically significant difference in perinatal outcomes between the two groups.

CONCLUSIONS

The incidence of adverse perinatal outcomes in pregnant women with T1D was high. This study innovatively suggested that metformin could be safe and could contribute to improving glucose management in pregnant women with T1D.