Fertility outcomes in women with pre-existing type 2 diabetes-a prospective cohort study

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.

Estimating the impact of bias in causal epidemiological studies: the case of health outcomes following assisted reproduction

Researchers interested in causal questions must deal with two sources of error: random error (random deviation from the true mean value of a distribution), and bias (systematic deviance from the true mean value due to extraneous factors). For some causal questions, randomization is not feasible, and observational studies are necessary. Bias poses a substantial threat to the validity of observational research and can have important consequences for health policy developed from the findings. The current piece describes bias and its sources, outlines proposed methods to estimate its impacts in an observational study, and demonstrates how these methods may be used to inform debate on the causal relationship between medically assisted reproduction (MAR) and health outcomes, using cancer as an example. In doing so, we aim to enlighten researchers who work with observational data, especially regarding the health effects of MAR and infertility, on the pitfalls of bias, and how to address them. We hope that, in combination with the provided example, we can convince readers that estimating the impact of bias in causal epidemiologic research is not only important but necessary to inform the development of robust health policy and clinical practice recommendations.

Histologic Remission in Inflammatory Bowel Disease and Female Fertility: A Nationwide Study

BACKGROUND & AIMS

Inflammatory bowel disease (IBD) is linked to reduced female fertility, but it is unclear how fertility rates vary by histologic disease activity.

METHODS

Nationwide IBD cohort of Swedish women aged 15 to 44 years. We examined fertility rates during periods with vs without histologic inflammation (n = 21,046; follow-up, 1990-2016) and during periods with vs without clinical activity (IBD-related hospitalization, surgery, or treatment escalation) (n = 24,995; follow-up, 2006-2020). Accounting for sociodemographics and comorbidities, we used Poisson regression to estimate adjusted fertility rate ratios (aFRRs) for live births conceived during 12-month periods of histologic inflammation (vs histologic remission) and 3-month periods of clinically active IBD (vs quiescent IBD).

RESULTS

During periods with vs without histologic inflammation, there were 6.35 (95% confidence interval [CI], 5.98-6.73) and 7.09 (95% CI, 6.48-7.70) live births conceived per 100 person-years of follow-up, respectively, or 1 fewer child per 14 women with 10 years of histologic inflammation (aFRR, 0.90; 95% CI, 0.81-1.00). In women with histologic inflammation, fertility was similarly reduced in ulcerative colitis (UC) (aFRR, 0.89 [95% CI, 0.78-1.02]) and Crohn's disease (CD) (aFRR, 0.86 [95% CI, 0.72-1.04]). Clinical IBD activity was associated with an aFRR of 0.76 (95% CI, 0.72-0.79) or 1 fewer child per 6 women with 10 years of clinical activity. Fertility was reduced in clinically active UC (aFRR, 0.75 [95% CI, 0.70-0.81]) and CD (aFRR, 0.76 [95% CI, 0.70-0.82]). Finally, among women with clinically quiescent IBD, histologic inflammation (vs histologic remission) was associated with reduced fertility (aFRR, 0.85 [95% CI, 0.73-0.98]).

CONCLUSIONS

An association between histologic and clinical activity and reduced female fertility in CD and UC was found. Notably, histologic inflammation was also linked to reduced fertility in women with clinically quiescent IBD.

Adverse effects of type 2 diabetes mellitus on ovarian reserve and pregnancy outcomes during the assisted reproductive technology process

Objective

To study the effect of type 2 diabetes mellitus(T2DM)on overall ovarian reserve and pregnancy outcomes during assisted reproductive technology (ART) among childbearing infertile women.

Design

Retrospective cohort study.

Setting

The Reproductive Medicine Special Hospital, The First Hospital of Lanzhou University, between January 2019 and December 2022.

Patients

A total of 265 infertile female patients aged 20-45 years who underwent in vitro fertilization-embryo transfer (IVF-ET), intracytoplasmic sperm injection-embryo transfer (ICSI-ET), or rescue intracytoplasmic sperm injection-embryo transfer (RICSI-ET) in the first fresh cycle.

Interventions

None.

Main Outcome Measures

Serum Anti-Müllerian Hormone (AMH) levels, clinical pregnancy rate (CPR), live birth rate (LBR), and abortion rate (AR) in the T2DM group and non-T2DM group.

Results

Patients with T2DM showed statistically decreased levels of AMH compared to the non-T2DM group. During ovarian stimulation, those with T2DM required significantly higher total and initial doses of gonadotropin (GN), although they had fewer retrieved oocytes and worse pregnancy outcomes than the non-T2DM group. Multivariate logistic regression analysis adjusting for confounding factors showed that T2DM alone was an independent risk factor for CPR and LBR (adjusted odds ratio [a OR], 0.458, adjusted 95% confidence interval [CI], 0.235-0.891, P = 0.022; a OR, 0.227, 95% CI, 0.101-0.513, P<0.001; respectively), and the abortion rate in the T2DM group was 3.316 times higher than the non-T2DM group(a OR, 3.316, 95%CI, 1.248-8.811, P = 0.016).

Conclusion

Infertile patients with T2DM have decreased ovarian reserve, and T2DM has a deleterious impact on clinical pregnancy outcomes during the ART process compared with non-T2DM infertile women.

Capsule

Infertile women with T2DM have decreased ovarian reserve and pregnancy outcomes during the assisted reproductive technology process compared with non-T2DM infertile women.

Infertility and Risk of Autism Spectrum Disorder in Children

Importance

Previous studies on the risk of childhood autism spectrum disorder (ASD) following fertility treatment did not account for the infertility itself or the mediating effect of obstetrical and neonatal factors.

Objective

To assess the association between infertility and its treatments on the risk of ASD and the mediating effect of selected adverse pregnancy outcomes on that association.

Design, Setting, and Participants

This was a population-based cohort study in Ontario, Canada. Participants were all singleton and multifetal live births at 24 or more weeks' gestation from 2006 to 2018. Data were analyzed from October 2022 to October 2023.

Exposures

The exposure was mode of conception, namely, (1) unassisted conception, (2) infertility without fertility treatment (ie, subfertility), (3) ovulation induction (OI) or intrauterine insemination (IUI), or (4) in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI).

Main Outcome and Measures

The study outcome was a diagnosis of ASD at age 18 months or older. Cox regression models generated hazard ratios (HR) adjusted for maternal and infant characteristics. Mediation analysis further accounted for the separate effect of (1) preeclampsia, (2) cesarean birth, (3) multifetal pregnancy, (4) preterm birth at less than 37 weeks, and (5) severe neonatal morbidity.

Results

A total of 1 370 152 children (703 407 male [51.3%]) were included: 1 185 024 (86.5%) with unassisted conception, 141 180 (10.3%) with parental subfertility, 20 429 (1.5%) following OI or IUI, and 23 519 (1.7%) following IVF or ICSI. Individuals with subfertility or fertility treatment were older and resided in higher-income areas; the mean (SD) age of each group was as follows: 30.1 (5.2) years in the unassisted conception group, 33.3 (4.7) years in the subfertility group, 33.1 (4.4) years in the OI or IUI group, and 35.8 (4.9) years in the IVF or ICSI group. The incidence rate of ASD was 1.93 per 1000 person-years among children in the unassisted conception group. Relative to the latter, the adjusted HR for ASD was 1.20 (95% CI, 1.15-1.25) in the subfertility group, 1.21 (95% CI, 1.09-1.34) following OI or IUI, and 1.16 (95% CI, 1.04-1.28) after IVF or ICSI. Obstetrical and neonatal factors appeared to mediate a sizeable proportion of the aforementioned association between mode of conception and ASD risk. For example, following IVF or ICSI, the proportion mediated by cesarean birth was 29%, multifetal pregnancy was 78%, preterm birth was 50%, and severe neonatal morbidity was 25%.

Conclusions and Relevance

In this cohort study, a slightly higher risk of ASD was observed in children born to individuals with infertility, which appears partly mediated by certain obstetrical and neonatal factors. To optimize child neurodevelopment, strategies should further explore these other factors in individuals with infertility, even among those not receiving fertility treatment.

OUP accepted manuscript

STUDY QUESTION

Is the presence of polycystic ovary syndrome (PCOS) associated with more adverse infant outcomes in mothers with different types of diabetes?

SUMMARY ANSWER

The presence of PCOS implies higher risks of total (medically indicated and spontaneously combined) and spontaneous preterm birth in mothers with non-insulin-treated type 2 diabetes and gestational diabetes mellitus (GDM), and lower risk of offspring being large for gestational age (LGA) in mothers with insulin-treated diabetes.

WHAT IS KNOWN ALREADY

PCOS is suggested to be an independent risk factor for adverse infant outcomes, and it is highly prevalent in mothers with diabetes. However, the impact of PCOS on the associations of different types of maternal diabetes with preterm birth and offspring birth sizes has not been reported.

STUDY DESIGN, SIZE, DURATION

This is a population-based cohort study including all live births between 1996 and 2014 in Finland. Children with concurrent maternal diagnoses that could cause signs and symptoms similar to PCOS were excluded. A total of 1 097 753 children were included.

PARTICIPANTS/MATERIALS, SETTING, METHODS

National registries were linked to identify births with maternal PCOS (n = 24 682), stratified by diabetes types. Logistic regression was used to examine the association of maternal PCOS and comorbid insulin-treated diabetes, non-insulin-treated type 2 diabetes or GDM with offspring LGA and small for gestational age (SGA). Generalized estimating equation was used to assess the risk of preterm birth in relation to maternal PCOS and diabetes. Potential interaction between PCOS and diabetes was evaluated on both additive and multiplicative scales.

MAIN RESULTS AND THE ROLE OF CHANCE

Using mothers with no PCOS and no diabetes as the reference and adjusting for maternal and birth factors, there were higher risks of total (odds ratio (OR) 2.84, 95% CI 2.21 − 3.66 vs. OR 1.91, 95% CI 1.77 − 2.07, P = 0.01) and spontaneous (OR 4.02, 95% CI 2.94 − 5.50 vs. OR 2.35, 95% CI 2.13 − 2.59, P = 0.001) preterm birth for those with PCOS in mothers with non-insulin-treated type 2 diabetes and higher risks of total (OR 1.42, 95% CI 1.27–1.58 vs. OR 0.89, 95% CI 0.86–0.91, P = 0.0001) and spontaneous (OR 1.80, 95% CI 1.59–2.05 vs. OR 1.01, 95% CI 0.98–1.05, P = 0.0001) preterm birth for those with PCOS in mothers with GDM. Among mothers with type 2 diabetes, further adjusting for maternal BMI eliminated the difference in preterm birth risks between those with and those without PCOS, and adjustment for infertility treatment and pre-eclampsia also reduced the preterm risks associated with PCOS significantly. For mothers with GDM, however, the risks of total and spontaneous preterm birth remained higher for those with PCOS following these aforementioned adjustments or stratified analysis. The risk of offspring being LGA was lower for those with PCOS than those without PCOS among mothers with insulin-treated diabetes (OR 18.90, 95% CI 14.21–25.14 vs. OR 32.04, 95% CI 29.79–34.46, P = 0.0001), showing departure from additivity (relative excess risk due to interaction −11.74, 95% CI −16.17 to −7.31, P < 0.001) and multiplicativity (P < 0.001). PCOS did not alter the risk estimate of preterm birth in mothers with insulin-treated diabetes or offspring LGA and SGA in mothers with type 2 diabetes or GDM.

LIMITATIONS, REASONS FOR CAUTION

The register-based diagnoses used in this study captured only women with PCOS seeking medical care and having live births. Including female infertility associated with anovulation as PCOS exposure was a risk for misclassification. Sample sizes for pregestational diabetes were small. Insulin purchase during pregnancy in those without a diabetes diagnosis was not accounted for in the analysis. For patients treated with insulin or other medications, we were unable to assess how they complied with such prescriptions. Also, maternal BMI was recorded only once in early pregnancy, thus the potential influence of gestational weight gain on birth outcomes could not be examined. Data on the causes for preterm birth were not available from the registers.

WIDER IMPLICATIONS OF THE FINDINGS

The presence of PCOS implied higher risks of total and spontaneous preterm birth in mothers with type 2 diabetes or GDM, and lower risk of offspring being LGA in mothers with insulin-treated diabetes. The higher risks of preterm birth added by PCOS could be explained by prepregnancy BMI or in part by infertility treatment and pre-eclampsia in maternal non-insulin-treated type 2 diabetes, but not in maternal GDM. The differential effects of PCOS on the associations of different types of maternal diabetes with infant outcomes have implications for preventative strategies and clinical counseling for affected pregnancies.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by Shandong Provincial Natural Science Foundation, China (ZR2020MH064 to X.C.), Shandong Province Medical and Health Technology Development Plan (2018WS338 to X.C.), the joint research funding of Shandong University and Karolinska Institute (SDU-KI-2019-08 to X.C. and C.L.), the Finnish National Institute for Health and Welfare: Drug and pregnancy project (M.G.), the Swedish Research Council (2014-10171 to C.L.), the regional agreement on medical training and clinical research (ALF) between Stockholm County Council and Karolinska Institute Stockholm County Council (SLL20170292 and SLL20190589 to C.L.), the Swedish Brain Foundation (FO2019-0201 and FO2020-0305 to C.L.). X.C. received grants from the China Scholarship Council at the beginning of the study. The authors have no competing interests to disclose.

TRIAL REGISTRATION NUMBER

N/A.

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.