Residual risk associations between initial hyperglycemia and adverse pregnancy outcomes in a large cohort including 6709 women with gestational diabetes

Association between hemoglobin A1c trajectory during pregnancy and adverse birth outcomes among non-gestational diabetic women

AIMS

Previous studies have shown that higher hemoglobin A1c (HbA1c) levels within the normal range during pregnancy can increase the risk of adverse birth outcomes. However, the effects of the longitudinal HbA1c trajectory during pregnancy on adverse birth outcomes among non-gestational diabetic women are poorly characterized. We aimed to identify HbA1c trajectory during pregnancy among non-gestational diabetic women and to estimate their associations with adverse birth outcomes.

METHODS

Data was extracted from the Information System of Guangdong Women and Children Hospital, China, from January 2017 to July 2022. This study involved 13,979 women who did not have gestational diabetes mellitus and underwent repeated HbA1c measurements during pregnancy. Latent mixture modeling was used to identify HbA1c trajectory groups. Logistic regression was applied to explore the associations between HbA1c trajectory groups and adverse birth outcomes, including preterm delivery, low birth weight, macrosomia, small for gestational age, and large for gestational age (LGA).

RESULTS

Three HbA1c trajectory groups were identified: low-stable (range 4.0% [20 mmol/mol]-4.4% [25 mmol/mol]), moderate-stable (range 4.6% [27 mmol/mol]-5.1% [32 mmol/mol]), and elevated-increasing (range 5.0% [31 mmol/mol]-5.6% [38 mmol/mol]). Compared with the low-stable HbA1c group, the elevated-increasing group had a higher risk of preterm delivery and LGA. The adjusted OR (95% CIs) were 1.67 (1.13, 2.49) and 1.47 (1.01, 2.12) for preterm delivery and LGA, respectively.

CONCLUSIONS

Among non-gestational diabetic women, the elevated-increasing HbA1c trajectory group was associated with a higher risk of preterm delivery and LGA. This finding emphasizes the importance of maintaining optimal HbA1c levels throughout pregnancy.

Maternal and neonatal outcomes according to the timing of diagnosis of hyperglycaemia in pregnancy: a nationwide cross-sectional study of 695,912 deliveries in France in 2018

AIMS/HYPOTHESIS

We aimed to assess maternal-fetal outcomes according to various subtypes of hyperglycaemia in pregnancy.

METHODS

We used data from the French National Health Data System (Système National des Données de Santé), which links individual data from the hospital discharge database and the French National Health Insurance information system. We included all deliveries after 22 gestational weeks (GW) in women without pre-existing diabetes recorded in 2018. Women with hyperglycaemia were classified as having overt diabetes in pregnancy or gestational diabetes mellitus (GDM), then categorised into three subgroups according to their gestational age at the time of GDM diagnosis: before 22 GW (GDM<22); between 22 and 30 GW (GDM22-30); and after 30 GW (GDM>30). Adjusted prevalence ratios (95% CI) for the outcomes were estimated after adjusting for maternal age, gestational age and socioeconomic status. Due to the multiple tests, we considered an association to be statistically significant according to the Holm-Bonferroni procedure. To take into account the potential immortal time bias, we performed analyses on deliveries at ≥31 GW and deliveries at ≥37 GW.

RESULTS

The study population of 695,912 women who gave birth in 2018 included 84,705 women (12.2%) with hyperglycaemia in pregnancy: overt diabetes in pregnancy, 0.4%; GDM<22, 36.8%; GDM22-30, 52.4%; and GDM>30, 10.4%. The following outcomes were statistically significant after Holm-Bonferroni adjustment for deliveries at ≥31 GW using GDM22-30 as the reference. Caesarean sections (1.54 [1.39, 1.72]), large-for-gestational-age (LGA) infants (2.00 [1.72, 2.32]), Erb's palsy or clavicle fracture (6.38 [2.42, 16.8]), preterm birth (1.84 [1.41, 2.40]) and neonatal hypoglycaemia (1.98 [1.39, 2.83]) were more frequent in women with overt diabetes. Similarly, LGA infants (1.10 [1.06, 1.14]) and Erb's palsy or clavicle fracture (1.55 [1.22, 1.99]) were more frequent in GDM<22. LGA infants (1.44 [1.37, 1.52]) were more frequent in GDM>30. Finally, women without hyperglycaemia in pregnancy were less likely to have preeclampsia or eclampsia (0.74 [0.69, 0.79]), Caesarean section (0.80 [0.79, 0.82]), pregnancy and postpartum haemorrhage (0.93 [0.89, 0.96]), LGA neonate (0.67 [0.65, 0.69]), premature neonate (0.80 [0.77, 0.83]) and neonate with neonatal hypoglycaemia (0.73 [0.66, 0.82]). Overall, the results were similar for deliveries at ≥37 GW. Although the estimation of the adjusted prevalence ratio of perinatal death was five times higher (5.06 [1.87, 13.7]) for women with overt diabetes, this result was non-significant after Holm-Bonferroni adjustment.

CONCLUSIONS/INTERPRETATION

Compared with GDM22-30, overt diabetes, GDM<22 and, to a lesser extent, GDM>30 were associated with poorer maternal-fetal outcomes.

Glycemic status during pregnancy according to fasting and post-load glucose values: The association with adverse pregnancy outcomes. An observational study

AIM

Prognosis of treated hyperglycemia in pregnancy (HIP) may differ according to whether diagnosis following an oral glucose tolerance test (OGTT) is based on high fasting and/or high post-load glucose values.

METHODS

From a multiethnic prospective study, we included 8,339 women screened for HIP after 22 weeks of gestation. We evaluated the risk of large-for-gestational-age (LGA) infant (primary endpoint) and other adverse pregnancy outcomes according to HIP status in four groups defined as follows: no HIP (n = 6,832, reference); isolated fasting HIP (n = 465), isolated post-load HIP (n = 646), and fasting and post-load HIP (n = 396).

RESULTS

After adjusting for age, body mass index, ethnicity, smoking during pregnancy and parity, compared with no HIP, the adjusted odds ratios [95% confidence interval] for LGA infant were higher in the isolated fasting HIP (1.47 [1.11-1.96]) and fasting and post-load HIP (1.65 [1.23-2.21]) groups, but not in the isolated post-load HIP (1.13 [0.86-1.48]) group. The adjusted odds ratios for preterm delivery and neonatal intensive care unit were higher in the post-load HIP group (1.44 [1.03-2.03] and 1.28 [1.04-1.57], respectively), the fasting and post-load HIP group (1.81 [1.23-2.68] and 1.42 [1.10-1.81], respectively) but not in the isolated fasting HIP group (1.34 [0.90-2.00] and 1.20 [0.94-1.52], respectively).

CONCLUSION

Despite glucose-lowering care and adjustment for confounders, compared with no HIP, fasting HIP was associated with a higher rate of LGA infant, whereas post-load HIP was associated with higher preterm delivery and neonatal intensive care unit admission rates.

Metformin in pregnancy and risk of abnormal growth outcomes at birth: a register-based cohort study

We previously reported an increased risk of being small for gestational age (SGA) and a decreased risk of being large for gestational age (LGA) after in utero exposure to metformin compared with insulin exposure. This follow-up study investigated if these observations remain when metformin exposure (henceforth, metformin cohort) is compared with non-pharmacological antidiabetic treatment of gestational diabetes mellitus (GDM; naïve cohort), instead of insulin. RESEARCH DESIGN AND METHODS : This was a Finnish population register-based cohort study from singleton children born during 2004-2016. Birth outcomes from metformin cohort (n=3964) and the naïve cohort (n=82 675) were used in the main analyses. Additional analyses were conducted in a subcohort, restricting the metformin cohort to children of mothers with GDM only (n=2361). Results were reported as inverse probability of treatment weighted OR (wOR), with the naïve cohort as reference. RESULTS  : No difference was found for the outcome of SGA between the cohorts in the main analyses (wOR 0.97, 95% CI 0.73 to 1.27) or in the additional analyses (wOR 1.01, 95% CI 0.75 to 1.37). No difference between the cohorts was found for the risk of LGA (wOR 0.91, 95% CI 0.75 to 1.11) in the main analyses but a decreased risk was observed in the additional analyses (wOR 0.72, 95% CI 0.56 to 0.92). CONCLUSIONS : This follow-up study found no increase in the risk of SGA or LGA after in utero exposure to metformin, compared with drug-naïve GDM. The decreased risk of LGA in mothers with GDM may suggest residual confounding. The lack of increased SGA risk aligns with findings from studies using metformin in non-diabetic pregnancies. In contrast, lower birth weight and increased SGA birth risk were observed in GDM pregnancies for metformin versus insulin. Metformin should be avoided with emerging growth restriction in utero. The interplay of intrauterine hyperglycemia and pharmacological treatments needs further assessment.

Is there a residual risk of large-for-gestational-age infant related to gestational diabetes mellitus when it is treated?

OBJECTIVE

The hyperglycaemia and adverse pregnancy outcomes (HAPO) study, where hyperglycaemia was untreated, showed a continuous association between large-for-gestational-age (LGA) infant and seven increasing categories of fasting plasma glucose (PG), 1-hour and 2-hour PG values after a 75 g oral glucose tolerance test at 24-32 gestational weeks. We evaluated whether the excess risk persisted in the 6th and 7th glucose categories - corresponding to women treated for gestational diabetes mellitus (GDM).

PATIENTS AND METHODS

We included 7,190 women meeting the HAPO criteria, of whom 655 (9.2%) were treated for GDM (dietary education in all; insulin therapy in 150 (20.3%)). We evaluated the adjusted odds ratio (aOR) for each glucose category (reference 1st category) for LGA infant.

RESULTS

The aOR for LGA linearly increased from the 1st to 5th categories of fasting, 1-hour and 2-hour PG. Specifically, the aORs for the 5th category were 2.20 (95% confidence interval 1.41-3.44), 2.25 (1.11-4.59), and 2.51 (1.63-3.85), respectively. The aORs for the 6th category were globally stable at 2.52 (1.46-4.36), 2.87 (1.48-5.54), and 2.47 (1.46-4.16), respectively. The same was true for the 7th category: 1.41 (0.56-3.55), 2.84 (1.03-7.86), and 3.53 (1.77-7.06), respectively.

CONCLUSION

We confirmed the association between increasing PG category and LGA infant in women without GDM. We did not observe a residual risk of LGA infant in women treated for GDM in our hospital, irrespective of elevated fasting, 1-hour, or 2-hour PG diagnosis. The risk of LGA infant was globally similar to that in women with high normal glucose values.