Gestational diabetes in twin pregnancy: prevalence and long-term implications

Association between triglyceride glucose-body mass index and gestational diabetes mellitus: a prospective cohort study

BACKGROUND

Limited research has examined the potential association between triglyceride glucose-body mass index (TyG-BMI) and gestational diabetes mellitus (GDM). The objective of this investigation was to analyze this linkage and evaluate TyG-BMI's capability to predict GDM.

METHODS

This research employed secondary data derived from a prospective cohort in South Korea, which included 588 pregnant women with singleton gestations, collected between November 2014 and July 2016. To investigate the connection between TyG-BMI and GDM, logistic regression and sensitivity analyses were performed. Furthermore, an analysis of receiver operating characteristics (ROC) was conducted to assess the prognostic accuracy of TyG-BMI in relation to GDM.

RESULTS

The cohort exhibited a mean age of 32.07 ± 3.80 years, with 36 individuals (6.12%) manifesting GDM during the interval of 24 to 28 weeks of gestation. Following the adjustment for possible confounding variables, an increased TyG-BMI was associated with an elevated risk of GDM, as indicated by an odds ratio (OR) of 1.02 (95% CI: 1.01-1.04). Additionally, the area under the curve (AUC) for TyG-BMI's predictive performance was recorded at 0.7979 (0.7143-0.8814), with an optimal threshold established at 211.03, which resulted in a specificity of 86.23% and a sensitivity of 66.67%.

CONCLUSIONS

In this South Korean cohort, increased TyG-BMI during early pregnancy (10-14 weeks) was significantly associated with the onset of GDM (during pregnancy 24-28 weeks). TyG-BMI could be integrated into clinical practice as a complementary preliminary screening tool for detecting women who are at increased risk of GDM.

Paradox in the research of gestational diabetes mellitus and twin pregnancies: Perspective and future directions

Gestational diabetes mellitus (GDM) is well known to be associated with fetal overgrowth and short- or long-term adverse outcomes in singleton pregnancies; however, its relationship with twin pregnancies remains controversial, posing challenges for clinical management. Despite the heterogeneity in GDM diagnosis and racial differences among populations, two critical issues remain unaddressed. The first issue is methodological, specifically whether data on twins have been analyzed using appropriate approaches. The second issue is the underlying pathophysiology'. Given that both glucose demand and insulin resistance are elevated in twin pregnancies, the optimal level of maternal insulin secretion remains uncertain. In this paper, we summarize the current knowledge on GDM in the context of twin pregnancies, their perinatal outcomes, glucose control, and gestational weight gain management. We then propose methodological considerations for future improvements. Ultimately, we underscore the importance of delving into the glucose requirements of twin pregnancies to gain a profound understanding of their gestational glucose and insulin metabolism. All these questions are key issues in this area, and by answering them we will accelerate the development of high-quality, evidence-based clinical guidelines for GDM management in twin pregnancies.

Gestational diabetes in twin pregnancies-a pathology requiring treatment or a benign physiological adaptation?

There is level-1 evidence that screening for and treating gestational diabetes in singleton pregnancies reduce maternal and neonatal morbidity. However, similar data for gestational diabetes in twin pregnancies are currently lacking. Consequently, the current approach for the diagnosis and management of gestational diabetes in twin pregnancies is based on the same diagnostic criteria and glycemic targets used in singleton pregnancies. However, twin pregnancies have unique physiological characteristics, and many of the typical gestational diabetes-related complications are less relevant for twin pregnancies. These differences raise the question of whether the greater increase in insulin resistance observed in twin pregnancies (which is often diagnosed as diet-treated gestational diabetes) should be considered physiological and potentially beneficial in which case alternative criteria should be used for the diagnosis of gestational diabetes in twin pregnancies. In this review, we summarize the most up-to-date evidence on the epidemiology, pathophysiology, and clinical consequences of gestational diabetes in twin pregnancies and review the available data on twin-specific screening and diagnostic criteria for gestational diabetes. Although twin pregnancies are associated with a higher incidence of diet-treated gestational diabetes, diet-treated gestational diabetes in twin pregnancies is less likely to be associated with adverse outcomes and accelerated fetal growth than in singleton pregnancies and may reduce the risk for intrauterine growth restriction. In addition, there is currently no evidence that treatment of diet-treated gestational diabetes in twin pregnancies improves outcomes, whereas preliminary data suggest that strict glycemic control in such cases might increase the risk for intrauterine growth restriction. Overall, these findings provide support to the hypothesis that the greater transient increase in insulin resistance observed in twin pregnancies is merely a physiological exaggeration of the normal increase in insulin resistance observed in singleton pregnancies (that is meant to support 2 fetuses) rather than a pathology that requires treatment. These data illustrate the need to develop twin-specific screening and diagnostic criteria for gestational diabetes to avoid overdiagnosis of gestational diabetes and to reduce the risks associated with overtreatment of diet-treated gestational diabetes in twin pregnancies. Although data on twin-specific screening and diagnostic criteria are presently scarce, preliminary data suggest that the optimal screening and diagnostic criteria in twin pregnancies are higher than those currently used in singleton pregnancies.

Twin Pregnancy Complicated by Gestational Diabetes Mellitus: Maternal and Neonatal Outcomes

Context

The risk of gestational diabetes mellitus (GDM) in twin pregnancies is more than double that of singleton pregnancies. Although twin pregnancies present unique challenges for fetal growth and prenatal management, the approach to GDM diagnosis and treatment is the same regardless of plurality. Data on pregnancy outcomes for individuals with GDM and a twin pregnancy are limited and conflicting.

Objective

To describe the maternal characteristics associated with GDM in twin pregnancies and to assess the associated pregnancy outcomes compared to twin pregnancies unaffected by GDM.

Methods

A retrospective cohort study was conducted at Mayo Clinic, Rochester, Minnesota, USA, and included predominantly Causasian women aged 18 to 45 years who received prenatal care for a twin pregnancy from 2017-2022. Maternal characteristics and a broad spectrum of pregnancy outcomes were evaluated. Universal GDM screening involved a 50 g oral glucose challenge test +/- a 100 g oral glucose tolerance test.

Results

GDM was diagnosed in 23% pregnancies (n = 104/452). Compared to those without, women with GDM had known risk factors including a higher prepregnancy body mass index (31.1vs 26.3 kg/m2; P < .01) and a prior history of GDM (21.7 vs 5.9%; P < .01). There were no differences in maternal pregnancy complications or neonatal outcomes between groups. Attendance at postpartum glucose testing among women with GDM was poor at 27.9% (29/104).

Conclusion

These data suggest that women with twin pregnancies share a similar GDM risk profile to those with singleton pregnancies and provide reassuring evidence that current management for GDM twin pregnancies produces similar outcomes to twin pregnancies without GDM.

Maternal diabetes following gestational diabetes: Does multiple gestation multiply the risk?

OBJECTIVE

To assess whether the risk for future diabetes is higher among women diagnosed with gestational diabetes (GD) during twin versus singleton gestations.

METHOD

A retrospective cohort study was performed including all women who delivered at a tertiary medical center between the years 1991 and 2021 and had at least one GD diagnosis. The first GD diagnosis per women was defined as the index pregnancy. Women diagnosed with GD during multiple gestations were compared with women diagnosed with GD during singleton gestations. The outcomes included first hemoglobin A1C (Hba1C) level > 6.4 mg/dL post partum, and the highest level measured during the follow-up period of up to 30 years. Multivariable logistic and Cox proportional analysis were used to compare the risk between the two groups while adjusting for confounding variables.

RESULTS

The current study included 13 770 mothers, with 458 patients (3.3%) diagnosed with GD during twin gestations and 13 312 (96.7%) during singleton gestations. The mean follow-up was 12.25 ± 9.3 years. Mothers of both groups did not differ in age at index pregnancy; however, mothers of twins were more likely to conceive following fertility treatments. Incidence of diabetes and prediabetes (defined as Hba1C > 6.4 and >5.7, respectively) were lower among the twin-gestation group, both during the 6-month postpartum period (for diabetes: 15.5% vs 22.1%; odds ratio [OR], 0.65 [95% confidence interval (CI), 0.46-0.91]) and during the long-term follow-up (for diabetes: 31.8% vs 40.7%; OR, 0.68 [95% CI, 0.52-0.88]). These results remained significant in the multivariable analysis, while accounting for age, ethnicity, and fertility treatments.

CONCLUSION

GD diagnosis during multiple versus singleton gestations is associated with a lower risk for future diabetes.

Gestational Diabetes in Twin Versus Singleton Pregnancies With Normal Weight or Overweight Pre-Pregnancy Body Mass Index: The Mediating Role of Mid-Pregnancy Weight Gain

BACKGROUND

Gestational diabetes might be more common in twin versus singleton pregnancies, yet the reasons for this are unclear. We evaluated the extent to which this relationship is explained by higher mid-pregnancy weight gain within normal weight and overweight pre-pregnancy body mass index (BMI) strata.

METHODS

We analyzed serial weights and glucose screening and diagnostic data abstracted from medical charts for twin (n = 1397) and singleton (n = 3117) pregnancies with normal or overweight pre-pregnancy BMI delivered from 1998 to 2013 at Magee-Womens Hospital in Pennsylvania. We used causal mediation analyses to estimate the total effect of twin versus singleton pregnancy on gestational diabetes, as well as those mediated (natural indirect effect) and not mediated (natural and controlled direct effects) by pathways involving mid-pregnancy weight gain.

RESULTS

Odds of gestational diabetes were higher among twin pregnancies [odds ratios (ORs) for total effect = 2.83 (95% CI = 1.54, 5.19) for normal weight and 2.09 (95% CI = 1.16, 3.75) for overweight pre pregnancy BMI], yet there was limited evidence that this relationship was mediated by mid-pregnancy weight gain [ORs for natural indirect effect = 1.21 (95% CI = 0.90, 1.24) for normal weight and 1.06 (95% CI = 0.92, 1.21) for overweight pre-pregnancy BMI] and more evidence of mediation via other pathways [ORs for natural direct effect = 2.34 (95% CI = 1.24, 4.40) for normal weight and 1.97 (95% CI = 1.08, 3.60) for overweight pre-pregnancy BMI].

CONCLUSIONS

While twin pregnancies with normal weight or overweight pre-pregnancy BMI experienced higher odds of gestational diabetes versus singletons, most of this effect was explained by pathways not involving mid-pregnancy weight gain.

Multiple gestation associated with infertility therapy: a committee opinion

This Committee Opinion provides practitioners with suggestions to reduce the likelihood of iatrogenic multiple gestation resulting from infertility treatment. This document replaces the document of the same name previously published in 2012 (Fertil Steril 2012;97:825-34 by the American Society for Reproductive Medicine).

The screening performance of glucose challenge test for gestational diabetes in twin pregnancies: a systematic review and meta-analysis

BACKGROUND

The screening accuracy of the 50 g-glucose challenge test (50 g-GCT) for gestational diabetes (GDM) has been described in singleton pregnancies. Given the physiologic differences and greater increase in insulin resistance in twin compared with singleton pregnancies, the performance of the 50 g-GCT in twin pregnancies may differ.

OBJECTIVES

To perform a systematic review on the screening performance of the 50 g-GCT for gestational diabetes in twin pregnancies.

DATA SOURCES

Ovid Medline, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL).

STUDY ELIGIBILITY CRITERIA, PARTICIPANTS, AND INTERVENTIONS

We included randomized controlled trials or cohort studies that evaluated the screening accuracy of the 50 g-GCT for GDM in twin pregnancies using the two-step approach. The primary outcome was the positive predictive value of the 50 g-GCT for GDM using the 140 mg/dL (7.8 mmol/L) threshold.

STUDY APPRAISAL AND SYNTHESIS METHODS

Methodological quality of included studies was assessed using the QUADAS-2 tool. The positive predictive value (PPV) was pooled for studies that used similar test characteristics.

RESULTS

From 2044 citations, 7 retrospective cohort studies with a total of 55,597 participants were included (6.5% twins and 93.5% singletons). The majority of studies evaluated a 50-g GCT cutoff point of 140 mg/dL. The pooled PPV for a threshold of 140 mg/dL (7.8 mmol/L) for twins was 22.58% (95% CI: 0.1912-0.2647, I²=34.1%). The 50-g GCT screen positive rate in twin pregnancies was higher than that in singleton pregnancies. None of the studies performed routine OGTT.

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

The PPV of 50 g-GCT for GDM in twin pregnancies when using a threshold of 140 mg/dL (7.8 mmol/L) is approximately 23%. There is currently no data on the sensitivity and specificity of the 50 g-GCT in twins.

Mature Follicle Count and Multiple Gestation Risk Based on Patient Age in Intrauterine Insemination Cycles With Ovarian Stimulation

OBJECTIVE

To estimate the risk of a multiple gestation pregnancy in ovarian stimulation intrauterine insemination (IUI) cycles when stratified by patient age and mature follicle number.

METHODS

We conducted a retrospective cohort study at a single private practice fertility center of IUI cycles performed from 2004 to 2017. Intervention(s) were ovarian stimulation and IUI if postwash total motile sperm count was more than 8 million. Mature follicles were defined as 14 mm or more as measured on the day of ovulation trigger. Main outcomes and measures were rates of clinical pregnancy and multiple gestation.

RESULTS

We identified 24,649 women who underwent a total of 50,473 IUI cycles. Increasing the number of mature follicles from one to five at the time of IUI in women younger than age 38 years increased the clinical pregnancy rate from 14.6% to 21.9% (adjusted odds ratio [aOR] 1.6, 95% CI 1.4-1.9), almost entirely from a marked increase in multiple gestations per cycle from 0.6% to 6.5% (aOR 9.9, 95% CI 6.9-14.2). There was little increase in singleton pregnancies per IUI (14.1-16.4%) regardless of mature follicle number. The per-pregnancy twin and higher-order multiple gestation risk significantly increased (3.9-23.3%, P<.01 and 0.2-10.6%, P<.01, respectively) when comparing one with five mature follicles present at the time of IUI (P<.01). In women younger than age 38 years with more than three follicles present, more than one quarter of all pregnancies were multiples. Similar findings occurred in women aged 38-40 years. In women older than age 40 years, up to four follicles tripled the odds of pregnancy (aOR 3.1, 95% CI 2.1-4.5) while maintaining a less than 12% risk of multiple gestation per pregnancy and a 1.0% absolute risk of multiples.

CONCLUSION

Caution should be used in proceeding with IUI after ovarian stimulation when there are more than two mature follicles in women younger than age 40 years owing to the substantially increased risk of multiple gestation without an improved chance of singleton clinical pregnancy.

Incidence and risk factors for gestational diabetes mellitus in twin versus singleton pregnancies

OBJECTIVE

To compare the incidence and risk factors for gestational diabetes mellitus (GDM) between women with twin and singleton pregnancies.

METHODS

Retrospective study of all women who had a twin or singleton birth in Ontario (2012-2016). Risk ratios (RR) and 95% CIs for GDM (stratified by type of treatment) were adjusted for relevant confounding variables. Multivariable Poisson regression analysis was used to identify risk factors for GDM in twin and singleton gestations.

RESULTS

Of 270,843 women who met inclusion criteria, 266,942 (98.6%) and 3901 (1.4%) had a singleton and a twin pregnancy, respectively. Women with twins had a significantly higher risk for overall GDM (aRR = 1.13, 95% CI 1.01-1.28) and diet-treated GDM (aRR = 1.20, 95% CI 1.01-1.42) while the association with insulin-treated GDM was not significant (aRR = 1.07, 95% CI 0.89-1.28). Maternal age ≥ 35 years, non-Caucasian ethnicity and BMI > 30 kg/m² were independent risk factors for GDM among women with twins and singletons, and the magnitude of the association of these factors with GDM was similar.

CONCLUSIONS

Women with twins are at increased risk of GDM, mainly due to a higher rate of diet-treated GDM. Despite higher baseline risk of GDM in women with twins, the effect of known risk factors for GDM is similar to that observed in singletons.

Analysis of the main risk factors for gestational diabetes diagnosed with International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria in multiple pregnancies

INTRODUCTION

The aim is to investigate the proportion of multiple pregnancies with gestational diabetes mellitus (GDM) diagnosed using the International Association of Diabetes and Pregnancy Study Groups (IADPSG) criteria and to identify the impact of age, body mass index (BMI), and mode of conception on incidence of GDM.

MATERIALS AND METHODS

This is a single center, retrospective cohort study on 656 multiple pregnancies screened for GDM with 75-g, 2-h oral glucose tolerance test at 24-28 weeks of gestation, between January 2010 and January 2016. The diagnosis of gestational diabetes mellitus (GDM) was reached through the IADPSG.

RESULTS

The incidence of GDM in our population was 15.1%. When patients who conceived through heterologous assisted reproduction technology were compared with those who conceived spontaneously, there was a significant difference for GDM (31.1 vs 13.6%, p < 0.001, OR 2.86). A similar finding was also observed comparing egg donation IVF/ICSI patients with homologous IVF/ICSI patients (31.1 vs 14.8%, p = 0.006, OR 2.59). Incidence of GDM was significantly higher in obese than in non-obese patients (42.5 vs 14.8%, p < 0.001, OR 4.88) and in women over 35 compared to younger patients (18.4 vs 11.1%, p = 0.01, OR 1.81). Logistic regression comparing the diabetes onset with conception mode gave a p = 0.07. The calculation of the Chi-square and odds ratio for single mode of conception showed that homologous vs conceived spontaneously p = 0.90, OR 0.97, heterologous vs homologous p = 0.01 with OR 2.46, and heterologous vs conceived spontaneously p = 0.01 with OR 2.39. Logistic regression showed that age and BMI are risk factors for developing GDM, respectively, p = 0.03 with OR 1.4 and p < 0.01 and OR 1.09.

DISCUSSION

The contribution our study can make is improved counseling about GDM risks for couples with multiple pregnancies. Our data support the role of age, BMI, and mode of conception as risk factors for GDM in multiple pregnancies.

Outcomes of twin pregnancies complicated by gestational diabetes: a meta-analysis of observational studies

OBJECTIVE

Gestational diabetes mellitus (GDM) in singleton pregnancy is associated with large for gestational age neonates and adverse perinatal outcomes; however, the impact of GDM in twin pregnancy is unclear. Thus, the aim of this study is to assess the perinatal outcomes of twin pregnancies complicated by GDM by performing a meta-analysis of observational studies.

STUDY DESIGN

Studies investigating GDM in twin pregnancy were identified through an online search of three databases: Medline, Embase and Web of Science. Selection criteria comprised full paper observational studies (retrospective or prospective) published in English that examined GDM in twin pregnancy compared with non-GDM twin pregnancy and reported on birth weight and/or adverse perinatal outcomes. Random-effects models with inverse-variance weighting were used to calculate standardized mean differences and unadjusted odds ratios. Sensitivity analyses were carried out to determine the impact of possible maternal confounders (body mass index and age) and GDM diagnostic criteria on perinatal outcomes.

RESULTS

Thirteen observational studies were included. GDM twins were born at the same gestation as non-GDM twins, with marginally lower birth weight. There was no difference in the incidence of large or small for gestational age neonates. Although there was no correlation between GDM in twin pregnancy and respiratory distress, neonatal hypoglycemic or low Apgar score, GDM twins had a higher rate of neonatal intensive care unit admission (OR 1.49; 95% confidence interval: 1.10, 2.02; P<0.01).

CONCLUSION

Identification and subsequent treatment of GDM in twin pregnancy demonstrates a similar risk of adverse perinatal outcomes compared with non-GDM twin pregnancies.

Glucose tolerance in singleton, twin and triplet pregnancies

BACKGROUND

Data regarding the effects of multifetal pregnancy on the incidence of gestational diabetes mellitus (GDM) are inconsistent and even conflicting. Twin pregnancies have been associated with no increase, a marginal increase or a higher incidence of gestational diabetes. In triplet pregnancies, these effects have not been investigated yet.

OBJECTIVES

To analyze the results of the glucose challenge and tolerance tests in singleton, twin and triplet pregnancies.

STUDY DESIGN

A retrospective database analysis of pregnant women with singletons, twins or triplets who had complete results of the 50 g glucose challenge test (GCT) and the 100 g oral glucose tolerance test (OGTT). The cohort included 12,382 singletons, 515 twins and 39 triplets.

RESULTS

There were significantly higher rates of abnormal GCTs in twins and triplets compared to singletons (45.4% and 33.3%, respectively vs. 13.7%, P<0.001 and P<0.05). Significantly higher rates of gestational diabetes in twins (10.1% vs. 2.9 %, P<0.001) and triplets (12.8% vs. 2.9%, P<0.05) compared to singletons were observed. Mean glucose levels after the GCT were higher in twins compared to singletons, and even more in triplets (108 mg/dL in singletons vs. 120 mg/dL in twins vs. 129 mg/dL in triplets, P<0.001).

CONCLUSIONS

Glucose intolerance is aggravated in multifetal pregnancies. The likelihood of an abnormal GCT and gestational diabetes is higher in twins and triplets compared to singletons.

Comparison of the performance of screening test for gestational diabetes in singleton versus twin pregnancies

Objective

We compared the performance of the 50-g glucose challenge test (GCT) in singleton versus twin pregnancies and investigated the need for adjusting GCT cutoff values for gestational diabetes mellitus (GDM) in twin pregnancies among Korean women.

Methods

A retrospective chart review was performed in women who underwent GCT at 24 to 28 weeks' gestation and delivered in our department between January 2000 and April 2008. GCT performance was compared between singleton and twin pregnancies for an ideal cutoff value of the GCT for GDM screening.

Results

GCT results were available in 3,578 pregnancies (3,435 singleton and 143 twin pregnancies). The mean GCT value was higher in the twin group than in the singleton group. Women in the twin group had a higher mean GCT value (P=0.043) and a higher incidence of GCT ≥130, ≥135, and ≥140 mg/dL (P=0.014, 0.005, and 0.015, respectively). The false positive rate for GCT ≥140 mg/dL was significantly higher in the twin than in the singleton group (P=0.042). The optimal GCT screening cutoff value appears to be ≥145 mg/dL in twin pregnancies.

Conclusion

Our study demonstrates that the GCT is associated with a higher false positive rate in twin rather than singleton pregnancies. This study suggests we should consider adjusting the GCT cutoff value for GDM in Korean twin pregnancies.

Outcome of twin pregnancies associated with glucose intolerance

OBJECTIVES

There is little information about the impact of hyperglycaemia in twin pregnancies. The objective of our study was to evaluate the maternal, foetal and neonatal complications in patients with twin pregnancy and glucose intolerance defined by gestational diabetes mellitus and gestational mild hyperglycaemia.

STUDY DESIGN

We performed a single-centre retrospective study. Screening for gestational diabetes was achieved by a two-step method. Patients were managed according to the French guidelines. After matching for age and body mass index, outcomes were compared in 177 patients with glucose intolerance and 509 controls. Macrosomia was defined as birth weight above the 90th percentile of gestational age adjusted for parity, foetal sex and maternal biometrics.

RESULTS

Prevalence of glucose intolerance was 17.5% in our population. Complications of pregnancy and mode of delivery were similar between the two groups. Caesarean section was associated with age >35 years, vascular complications of pregnancy and non-cephalic presentation of the first twin. Rate of macrosomia was not different between the two groups. The only risk factor for macrosomia was a history of macrosomia in a previous pregnancy (odds ratio = 5.9, 95% confidence interval = 1.8-19.2).

CONCLUSION

Twin pregnancies complicated by glucose intolerance were not associated with an increased risk of macrosomia or Caesarean section. Further studies should assess the value of screening gestational diabetes mellitus in twin pregnancies.

Screening approach for gestational diabetes in twin pregnancies

OBJECTIVE

The objective of this study was to evaluate the ideal cutoff for the glucose challenge test (GCT) in twin pregnancies undergoing screening for gestational diabetes mellitus (GDM).

STUDY DESIGN

A historical cohort of patients with twin pregnancies were identified from 1 maternal-fetal medicine practice from 2005 through 2013. All patients were administered a 1-hour, 50-g GCT between 24-28 weeks' gestation. All patients with a GCT of ≥130 mg/dL underwent a 3-hour, 100-g oral glucose tolerance test. The diagnosis of GDM was made if 2 of the 4 values on the oral glucose tolerance test were abnormal (Carpenter and Coustan). The testing characteristics of the GCT for diagnosis of GDM were evaluated using 3 selected cutoffs: ≥130, ≥135, and ≥140 mg/dL. We excluded all patients diagnosed with GDM <24 weeks.

RESULTS

In all, 475 patients with twin pregnancies underwent a GCT between 24-28 weeks. The incidence of GDM was 6.5%. The positive screen rate using the 3 selected cutoffs were: ≥130 mg/dL, 34.7%; ≥135 mg/dL, 28.6%; and ≥140 mg/dL, 23.4%. A GCT cutoff of ≥135 mg/dL maintained 100% sensitivity, with a specificity of 76.4%. Using this cutoff, the positive predictive value was 22.8% and the negative predictive value was 100%. Compared to a cutoff of ≥130 mg/dL, a cutoff of ≥135 mg/dL resulted in 6.1% less patients testing positive while maintaining the same 100% sensitivity.

CONCLUSION

In twin pregnancies, the optimal 1-hour, 50-g GCT screening cutoff appears to be ≥135 mg/dL.

Refuting a misguided campaign against the goal of single-embryo transfer and singleton birth in assisted reproduction

Much recent progress has been made by assisted reproductive technology (ART) professionals toward minimizing the incidence of multiple pregnancy following ART treatment. While a healthy singleton birth is widely considered to be the ideal outcome of such treatment, a vocal minority continues a campaign to advocate the benefits of multiple embryo transfer as treatment and twin pregnancy as outcome for most ART patients. Proponents of twinning argue four points: that patients prefer twins, that multiple embryo transfer maximizes success rates, that the costs per infant are lower with twins and that one twin pregnancy and birth is associated with no higher risk than two consecutive singleton pregnancies and births. We find fault with the reasoning and data behind each of these tenets. First, we respect the principle of patient autonomy to choose the number of embryos for transfer but counter that it has been shown that better patient education reduces their desire for twins. In addition, reasonable and evidentially supported limits may be placed on autonomy in exchange for public or private insurance coverage for ART treatment, and counterbalancing ethical principles to autonomy exist, especially beneficence (doing good) and non-maleficence (doing no harm). Second, comparisons between success rates following single-embryo transfer (SET) and double-embryo transfers favor double-embryo transfers only when embryo utilization is not comparable; cumulative pregnancy and birth rates that take into account utilization of cryopreserved embryos (and the additional cryopreserved embryo available with single fresh embryo transfer) consistently demonstrate no advantage to double-embryo transfer. Third, while comparisons of costs are system dependent and not easy to assess, several independent studies all suggest that short-term costs per child (through the neonatal period alone) are lower with transfers of one rather than two embryos. And, finally, abundant evidence conclusively demonstrates that the risks to both mother and especially to children are substantially greater with one twin birth compared with two singleton births. Thus, the arguments used by some to promote multiple embryo transfer and twinning are not supported by the facts. They should not detract from efforts to further promote SET and thus reduce ART-associated multiple pregnancy and its inherent risks.

The performance of the screening test for gestational diabetes in twin versus singleton pregnancies

OBJECTIVE

To compare the performance of the 50 g glucose challenge test (GCT) and the 100 g oral glucose tolerance test (OGTT) in twin versus singleton pregnancies.

METHODS

A retrospective study of all women who underwent a GCT (24-28 weeks) and delivered in a single tertiary medical center (2001-2012). The performance of the GCT and the OGTT tests were compared between twin and singleton pregnancies.

RESULTS

The results of the GCT were available for 14 797 women, of whom 14 268 were singleton and 529 were twin pregnancies. Women in the twins group were characterized by a higher mean GCT result (104.7 ± 28 versus 98.5 ± 25, p < 0.001), a higher rate of GCT > 130 mg/dl (20.2% versus 11.8%, p < 0.001) or GCT >140 mg/dl (13.8% versus 9.6%, p = 0.001). The positive prediction value (PPV) for a GCT >140 mg/dl was significantly lower in the twins group for the prediction of either ≥1 abnormal values (21.1% versus 33.8%, p = 0.03) or ≥2 abnormal values (12.7% versus 23.0%, p = 0.04) in the OGTT. Twin pregnancy was independently associated with an increased risk for a GCT result >130 mg/dl [odds ratio (OR) = 2.2, 95% confidence interval (CI) 1.7-2.7] or >140 mg/dl (OR = 1.9, 95% CI 1.5-2.5) even after adjustment for maternal age, parity and fetal sex.

CONCLUSION

The 50 g GCT appears to be associated with a higher false positive rate and a lower positive predictive value in twin compared with singleton pregnancies.

Definition, epidemiology, risk factors

Gestational diabetes mellitus is defined as glucose intolerance that begins or is first recognized during pregnancy. Its prevalence, generally situated between 2-6%, may reach 10-20% in high-risk populations, with an increasing trend across most racial/ethnic groups studied. Among traditional risk factors, previous gestational diabetes, advanced maternal age and obesity have the highest impact on gestational diabetes risk. Racial/ethnic origin and family history of type 2 diabetes have a significant but moderate impact (except for type 2 diabetes in siblings). Several non traditional factors have been recently characterized, either physiological (low birthweight and short maternal height) or pathological (polycystic ovaries). The multiplicity of risk factors and their interactions results in a low reliability of risk prediction on an individual basis.

Perinatal outcome in twin pregnancies complicated by gestational diabetes mellitus: a comparative study

The purpose of this study is to compare perinatal outcomes of twin pregnancies complicated by gestational diabetes (GDM) with those unaffected by GDM. A total of 1,154 twin pregnancies who delivered at Cheil General Hospital, between January 1998 and December 2002 were recruited to participate in a retrospective analysis. Out of these twin pregnancies, 37 women were had GDM. Four pregnancies exposed to GDM were excluded due to the loss of medical records; therefore 33 twin pregnancies exposed to GDM were enrolled. We matched the GDM pregnancies with pregnancies unaffected by GDM in a 1:2 ratio; therefore there were 33 GDM/66 without GDM who delivered during the study period. Our findings show that there were no significant differences including birth weight, Apgar score, respiratory distress syndrome, meconium aspiration pneumonia, transient tachypnea of new born, hyperbilirubinemia, hypoglycemia, hypocalcemia and congenital anomalies. Therefore, well controlled GDM may not increase perinatal complications in twin pregnancies. Careful pregnancy management and fetal surveillance in twin pregnancies is important to decrease perinatal complications and maintain a sound pregnancy and healthy offspring.

Low dose recombinant FSH treatment may reduce multiple gestations caused by controlled ovarian hyperstimulation and intrauterine insemination

OBJECTIVE

To evaluate the rate of multiple pregnancies in intrauterine insemination cycles stimulated with a minimal dose of recombinant follicle stimulating hormone (rec-FSH).

DESIGN

Retrospective study.

SETTING

University Medical Center.

POPULATION

A total of 1256 patients underwent 3219 consequent intrauterine insemination cycles with minimal ovarian stimulation.

METHODS

Patients received 50 or 75 IU of rec-FSH from day four to day seven. The dose was adjusted according to oestradiol (E(2)) levels in order to achieve a maximum of two follicles on the day of hCG administration.

MAIN OUTCOME MEASURES

Peak E(2) levels, the number of follicles >15 mm and pregnancy rates were calculated. The predictive value of E(2) levels for multiple gestations was also estimated.

RESULTS

Of 3219 cycles, 334 resulted in pregnancies (10%). Of these, 238 (91%) were singletons, 28 (8%) twins and 1 (0.3%) was a triplet. The cumulative overall pregnancy rate was 43%. Patients over 40 years old had a significantly lower pregnancy rate per cycle and overall live birth rate (P < 0.05). Most pregnancies (83%) occurred during the first three cycles. Pregnancy rates per cycle varied from 8% for tubal factor to 14% for anovulation infertility.

CONCLUSIONS

Minimal FSH stimulation in intrauterine insemination cycles may reduce the rates of twins and high order multiple pregnancies without affecting overall pregnancy rates.

Twin pregnancy outcomes for women with gestational diabetes mellitus compared with glucose tolerant women

OBJECTIVE

To examine pregnancy outcomes for women with gestational diabetes mellitus (GDM) and a twin pregnancy compared with glucose tolerant women with a twin pregnancy.

DESIGN

Comparison of selected pregnancy outcomes.

SETTING

Wollongong, New South Wales, Australia.

POPULATION

Women with GDM seen over a 10-year period by an endocrinologist, and women from a selected year of an obstetric database including Wollongong and Shellharbour Hospitals.

METHODS

Examination of pregnancy outcome data from the two sources.

MAIN OUTCOME MEASURES

Fetal birthweights and method of delivery.

RESULTS

There were 28 GDM women with a twin pregnancy from 1229 consecutive referrals (2.3%) of women with GDM for medical management. For comparison there were 29 glucose tolerant women with twin pregnancies evaluable who had delivered over a 1-year period. For the women with GDM and a twin pregnancy there were no significant differences in demographics or outcomes except for a higher rate of elective Caesarean section.

CONCLUSION

The higher rate of Caesarean section appeared to be related to the combination of a twin pregnancy and GDM rather than the twin pregnancy or the GDM independently.

Gestational diabetes mellitus: metabolic and blood glucose parameters in singleton versus twin pregnancies

OBJECTIVES

This study compared the frequency, glucose tolerance test results, and parameters of blood glucose control in twin and singleton pregnancies associated with gestational diabetes mellitus and carbohydrate intolerance.

STUDY DESIGN

Twin and singleton pregnancies associated with gestational diabetes mellitus and carbohydrate intolerance were compared as follows: frequency, maternal age, weight, 1-hour screen, glucose tolerance test results, posttreatment blood glucose values, insulin requirement, and insulin dose. Statistical analysis included the chi(2) and Student t tests.

RESULTS

Gestational diabetes mellitus was increased in twins (7.7% vs 4.1%; P <.05). The maternal weight at first visit was significantly less, and the 3-hour glucose tolerance test value was significantly greater than that for singletons. The other parameters were not different.

CONCLUSIONS

There is a significant increase in the incidence of gestational diabetes mellitus and disturbance of the 3-hour glucose tolerance test in twin pregnancies. However, insulin requirements were not different, suggesting a mild disturbance of carbohydrate tolerance that was effectively managed by the strategies used to achieve blood glucose control in singletons.