Gestational diabetes mellitus (GDM) increases the risk of adverse maternal and perinatal outcomes in singleton and twin pregnancies, according to a recent study published in the American Journal of Obstetrics & Gynecology.
Takeaways
- The study highlights that gestational diabetes mellitus (GDM) poses heightened risks for adverse maternal and perinatal outcomes in both singleton and twin pregnancies, necessitating closer monitoring and management during pregnancy.
- Rising rates of GDM are attributed to factors such as increasing maternal age, obesity, and the growing utilization of in vitro fertilization, particularly in twin pregnancies, highlighting the importance of addressing these contributing factors in prenatal care.
- Contrary to previous hypotheses, the research suggests that while twin pregnancies have seen an increase in GDM rates, the risks associated with GDM complications are comparable between singleton and twin pregnancies, indicating a need for consistent vigilance in managing GDM across all pregnancy types.
- The study delves into various adverse outcomes associated with GDM, including hypertensive disorders of pregnancy, cesarean delivery, small and large for gestational age neonates, preterm birth, and neonatal intensive care unit admissions, providing comprehensive insights into the potential complications of GDM.
- Despite the findings, the study underscores the necessity for additional research to establish optimal diagnostic thresholds for GDM in twin pregnancies, suggesting that current diagnostic criteria may not fully capture the nuances of GDM in this specific population, highlighting avenues for future investigation and improvement in clinical practice.
GDM, diagnosed during pregnancy when glucose tolerance is impaired, has had increasing incidence over previous decades. The rise in GDM incidence has been linked to rising rates of obesity and maternal age. Twin pregnancies have also had rising incidence because of increased maternal age and in vitro fertilization use, accounting for approximately 3% of births.
Since GDM and twin pregnancy rates have risen, a hypothesis has formed that twin pregnancies may have increased risk of GDM complications. However, data has indicated similar risks when comparing twin pregnancies to controls. This has made it unclear whether maternal and perinatal outcomes of GDM differ between singleton and twin pregnancies.
To evaluate maternal and perinatal risks in twin and singleton pregnancies impacted by GDM, investigators conducted a systematic review and meta-analysis. Literature was found through searches of the MEDLINE, Embase, and Cochrane databases.
Eligibility criteria included being published between January 1980 and May 2023, being a full observational study, comparing maternal and perinatal outcomes in pregnancies with GDM to those without GDM, and being stratified to singleton or twin pregnancies. Titles and abstracts were screened by 2 independent reviewers, with a third consulted during disagreements.
Data extraction was completed using an extraction sheet on Microsoft Excel and included study characteristics, details of GDM screening and management, GDM prevalence, and maternal demographics. Chorionicity data was also extracted for studies evaluating twin pregnancies.
Cesarean delivery (CD), induction of labor (IOL), postpartum hemorrhage, hypertensive disorders of pregnancy (HDPs), preterm premature rupture of membranes, and placental abruption were reported as adverse maternal outcomes.
Small for gestational age (SGA), large for gestational age (LGA), preterm birth, low Apgar score, neonatal intensive care unit (NICU) admission, stillbirth, neonatal death (NND), and perinatal mortality were reported as adverse perinatal outcomes.
There were 108 studies included in the final analysis, 81 evaluating singleton pregnancies, 23 twin pregnancies, and 4 both. For singleton pregnancies, 722,020 were impacted by GDM and 13,308,855 were controls. For twin pregnancies, 11,812 were complicated by GDM and 156,179 were controls.
Among mothers of singleton and twin pregnancies complicated by GDM, HDPs were reported in 9.6% and 18.3%, respectively. The risk ratio (RR) of HDPs in singleton pregnancies with GDM compared to those without GDM was 1.85. In twin pregnancies, the RR was 1.65. The difference in RR between singleton and twin pregnancies was not statistically significant.
IOL was reported in 25.2% of singleton pregnancies and 18.5% of twin pregnancies with GDM. The RRs for pregnancies with GDM compared to those without GDM were 1.36 and 1.20, respectively. The difference between these RRs was not statistically significant.
Of singleton and twin pregnancies complicated by GDM, 36.4% and 76%, respectively, reported CD. Singleton and twin pregnancies both had increased CD risk when complicated by GDM, with RRs of 1.31 and 1.10, respectively. This difference in RRs was statistically significant.
SGA neonates were reported in a mean 7.3% of singleton pregnancies and a mean 20% of twin pregnancies with GDM. In singleton pregnancies, the risk of SGA was not reduced by GDM complication, with an RR of 0.99. However, the RR of SGA for twin pregnancies complicated by GDM was 0.89, indicating reduced risk. This difference in RRs was not statistically significant.
In comparison, LGA neonates were reported in a mean 16.3% of singleton pregnancies and a mean 14.1% of twin pregnancies complicated by GDM. GDM was associated with increased LGA risk in singleton and twin pregnancies, with RRs of 1.61 and 1.29, respectively. This difference was not statistically significant.
Preterm birth was reported in a mean 12.1% of singleton pregnancies and 40.2% of twin pregnancies complicated by GDM, with RRs of 1.36 and 1.19, respectively. For low Apgar scores, the RRs were 1.12 and 0.9, respectively, indicating no increased risks. These differences were not statistically significant.
NICU admission had RRs of 1.43 for singleton pregnancies and 1.20 for twin pregnancies. While this difference was not statistically significant, it became significant when body mass index or parity were added to the model. Similarly, stillbirth RRs were not significantly different between pregnancy types unless age or diagnostic criteria were added to the model.
NND was reported in a mean 0.9% of singleton pregnancies and 0.88% of twin pregnancies. The RRs for these pregnancy types were not statistically significant, at 0.87 and 0.5, respectively. However, the inclusion of diagnostic criteria made the RR for NND significantly lower in twin pregnancies compared to singleton pregnancies.
Perinatal mortality had an RR of 0.89 for singleton pregnancies and 1.04 for twin pregnancies. This difference was not significantly significant.
These results indicated similar impacts of GDM on maternal and perinatal outcomes across singleton and twin pregnancies, though with milder impacts observed for GDM. Investigators concluded further research is necessary to determine the optimal thresholds for diagnosing GDM in twin pregnancies.
Reference
Greco E, Calanducci M, Nicolaides KH, Barry EVH, Huda MSB, Iliodromiti S, et al. Gestational diabetes mellitus and adverse maternal and perinatal outcomes in twin and singleton pregnancies: a systematic review and meta-analysis. American Journal of Obstetrics & Gynecology. 2024;230(2):213-225. doi:10.1016/j.ajog.2023.08.011
