Association Between Serum Glycated Hemoglobin Levels at Early Gestation and the Risk of Subsequent Pregnancy Loss in Pregnant Women Without Diabetes Mellitus: Prospective Cohort Study

BACKGROUND

As a severe morbidity during pregnancy, the etiology of spontaneous pregnancy loss (SPL) remains largely unknown. Serum glycated hemoglobin (HbA1c) level is an established predictor of SPL risk among women with diabetes, but little is known about whether such an association exists among pregnant women without diabetes when glycemic levels are within the normal range.

OBJECTIVE

This study aimed to quantify the association between maternal HbA1c levels in early pregnancy and subsequent SPL risk in a cohort of pregnant women without diabetes.

METHODS

This prospective cohort study involved 10,773 pregnant women without diabetes enrolled at their first antenatal care visit at a hospital's early pregnancy clinic from March 2016 to December 2018 in Shanghai, China. HbA1c and fasting blood glucose (FBG) levels were examined at enrollment. Participants with diabetes before or pregnancy or those diagnosed with gestational diabetes were excluded. Diagnosis of SPL, defined as fetal death occurring before 28 gestational weeks, was derived from medical records and confirmed via telephone interviews. We used generalized linear models to quantify the associations of continuous and dichotomized maternal HbA1c levels with SPL risk and reported crude and adjusted risk ratios (RRs) and 95% CIs. A restricted cubic spline (RCS) regression model was used to assess the potential nonlinear dose-response relationship. Adjusted covariates included maternal age, education level, preconception BMI, gestational weeks, gravidity, history of adverse pregnancy outcomes, family history of diabetes, folic acid supplementation, and smoking and drinking during the periconception period.

RESULTS

In total, 273 (2.5%) SPL cases occurred. Every 0.5% increase in HbA1c levels was linearly associated with a 23% increase in SPL risk (adjusted RR [aRR] 1.23; 95% CI 1.01-1.50). The RCS model revealed that this association was linear (P=.77 for the nonlinearity test). Analyses based on dichotomized HbA1c levels showed a significantly increased risk of SPL when HbA1c levels were ≥5.9% (aRR 1.67; 95% CI 0.67-3.67), and the significance threshold was ≥5.6% (aRR 1.60; 95% CI 1.01-2.54). Sensitivity analyses showed similar results when including the participants with missing SPL records or HbA1c data. Linear associations of HbA1c levels remained significant even in the subgroups without overweight, alcohol consumption, and a family history of diabetes and adverse pregnancy outcomes. Every 1 mmol/L increment in maternal FBG levels was associated with a >2-fold higher risk of SPL (aRR 2.12; 95% CI 1.61-2.80; P<.001).

CONCLUSIONS

Higher HbA1c levels in early pregnant women without diabetes are associated with an increased SPL risk in a dose-response manner. Pregnant women with an HbA1c level above 5.6% at early gestation need attention for its potentially increased risk for SPL. Our findings support the need to monitor HbA1c levels to identify individuals at high risk of subsequent SPL in the general population of pregnant women.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02737644; https://clinicaltrials.gov/study/NCT02737644.

Epidemiology of spontaneous pregnancy loss in Kazakhstan: A national population-based cohort analysis during 2014-2019 using the national electronic healthcare system

INTRODUCTION

Spontaneous pregnancy loss (SPL) is a common health problem that affects 1:10 of childbearing women, and is linked with physical and psychological complications. As the number of nationwide studies on the incidence of SPL is few, especially from middle-income countries, in this study we investigated the epidemiology, complications and outcomes of SPL before 22 weeks of gestation by analyzing large-scale healthcare data from the Unified Nationwide Electronic Healthcare System (UNEHS) in Kazakhstan.

MATERIAL AND METHODS

A population-based study among women who experienced SPL in any healthcare setting of the Republic of Kazakhstan during the period of 2014-2019. The International Classification of Diseases (ICD) 10th edition and ICD 9th edition's procedural codes were utilized to retrieve data using relevant diagnostic and procedural codes.

RESULTS

In total, 207 317 records of women who have experienced an SPL before 22 weeks of gestation were analyzed from all Kazakhstani regions. The estimated prevalence of SPL was 8.7%, with a 20% decline over a 6-year period. The SPL cases ratio comprises on average 6.2 per 1000 reproductive-age women. Incomplete miscarriage (ICD-10 code "O03.4") was the most common type (37.8%), followed by blighted ovum (ICD-10 code "O02.0"; 34.1%) and missed abortion (ICD-10 code "O02.1"; 13.5%). The most common management methods were dilation and curettage of the uterus (ICD-9 code "69.0"; 84.7%) and aspiration curettage of the uterus (ICD-9 code "65.0"; 15%), whereas medical management was rarely performed (2.6%).

CONCLUSION

The information available in UNEHS adequately identifies types of miscarriages and treatment methods. Although the prevalence of SPL before 22 weeks of gestation is decreasing, management of miscarriages requires closer attention.

Impact of daylight savings time on spontaneous pregnancy loss in in vitro fertilization patients

Transition into daylight savings time (DST) has studied negative impacts on health, but little is known regarding impact on fertility. This retrospective cohort study evaluates DST impact on pregnancy and pregnancy loss rates in 1,654 autologous in vitro fertilization cycles (2009 to 2012). Study groups were identified based on the relationship of DST to embryo transfer. Pregnancy rates were similar in Spring and Fall (41.4%, 42.2%). Pregnancy loss rates were also comparable between Spring and Fall (15.5%, 17.1%), but rates of loss were significantly higher in Spring when DST occurred after embryo transfer (24.3%). Loss was marked in patients with a history of prior spontaneous pregnancy loss (60.5%).

Interaction of apolipoprotein E gene polymorphisms on miscarriage risk in black and white American women

OBJECTIVE

To evaluate whether [1] apolipoprotein E (APOE) polymorphisms can differentially regulate miscarriage risk and [2] whether this genotype effect could also be modulated by the race within populations.

DESIGN

Data were derived from the Coronary Artery Risk Development in Young Adults (CARDIA), a longitudinal study with black and white participants from four U.S.

SETTING

Not applicable.

PATIENT(S)

Women without miscarriages (controls) and women who miscarried at least once (cases).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

A group of women (n = 1,372) successfully followed for 25 years and with their APOE alleles identified were analyzed for miscarriage risk throughout their reproductive life. Additionally, a larger longitudinal analysis encompassing all the participants who had their APOE characterized (n = 2,140) was also performed for the association between APOE and miscarriage risk.

RESULT(S)

In white women followed up for 25 years, the odds ratio for miscarriage associated with APOE*2 allele presence was 1.61 (95% confidence interval, 1.04-2.50) compared with APOE*33 carriers. This was a race-dependent phenomenon as no associations between APOE alleles and miscarriage was observed in black women. Likewise, Cox regression analysis showed that cumulative miscarriage risk in white women was 37.2% in the APOE*2 carriers compared with 27.8% and 24.8% in APOE*33 and APOE*4 carriers, respectively. With APOE*33 as the reference, the age-adjusted hazard ratio associated with carrying the APOE*2 allele was 1.47 (95 confidence interval, 1.06-2.05).

CONCLUSION(S)

This variable miscarriage risk, produced by an interaction between genotype and race, may reconcile, at least partially, the conflicting reports of the association of APOE and miscarriage risk.