European Journal of Cardiovascular Medicine

As we all know that in the current ages, Gestational diabetes mellitus (GDM) is one of the most frequent metabolic disorders during pregnancy, with incidence rates ranging from 1.1 to 14.3% depending on the adopted diagnostic criteria and the study population.[1] In Brazil, GDM affects 7% of all pregnancies.[2] This pathology is associated with several undesirable pregnancy outcomes, including an increased risk of premature rupture of the membranes, preterm birth, fetal macrosomia, and preeclampsia.[2]

In addition to the factors mentioned above, several others are associated with a higher incidence of cesarean deliveries, including: age above 30 years; occurrence of prior cesarean deliveries; first gestation; cervical dilation of 3 cm or less at the time of delivery; gestational age below 37 weeks or above 40 weeks; non-cephalic presentation; prior maternal pathology; previous use of oxytocin in the pre-partum; secondary or tertiary maternal education level; number of prenatal consultations greater or equal to 7; labor during daytime; and maternal overweightness or obesity.[4] [5] [6]

Even though the cesarean section has no absolute contraindications, this procedure, like any other surgical procedure, is not risk-free. In some occasions, however, the benefits associated with reducing the maternal-fetal morbidity and mortality outweigh the risks associated with performing a cesarean section.[3] [7] Some studies suggest that unplanned (emergency) cesarean sections result in increased maternal morbidity compared with planned cesareans.[8] Thus, it is important to identify which risk factors may lead to a requirement for cesarean delivery, so that the procedure can be planned in advance, if necessary, to avoid possible complications for both the mother and the fetus.

The objective of this study was to identify the risk factors related to birth by cesarean section in pregnant women with GDM.

This was a retrospective and descriptive study including a total of 392 pregnant women with GDM attending a public maternity hospital in central India from January 2022 to December 2023.

The study included pregnant women with GDM according to the diagnostic criteria of the International Association of Diabetes and Pregnancy Study Groups (IADPSG), aged 18 years or over, with a single gestation and without associated conditions. The participants who presented incomplete data in their medical records were excluded.

The primary outcomes evaluated were maternal age, maternal BMI, nulliparity, occurrence of a prior cesarean section, type of treatment used, glycemic levels, and FAC.

A total of 392 patients with GDM were analyzed, and none were excluded. Among the maternal characteristics, the mean age of the patients and the pregestational BMI were higher at the time the cesarean section was performed (p < 0.029 and p < 0.01 respectively).

(Table 1 comes here)

The gestational age at delivery, the weight of the newborn, the class of weight of the newborn according to the gestational age, and the Apgar score at the first and fifth minutes also did not differ significantly between the groups. The admission to the intensive care unit was the characteristic that came closest to having statistical significance (p = 0.052).

Regarding the BMI, when this parameter was categorized as adequate or indicating overweightness, the chance of cesarean delivery decreased by 0.7 and 0.4 times respectively, whereas obesity increased the chance of this procedure by 2.2 times.

Treatment with diet or the use of oral hypoglycemic agents and/or insulin, and the FAC did not influence the outcome.

Due to increased maternal and fetal complications arising from GDM, it becomes evident that abdominal delivery is a priority choice for many obstetricians, as observed in our study (57.4%). However, GDM alone is not an indication for cesarean section or for the interruption of the gestation before 38 weeks. In a study published by Moore et al[9] comparing cesarean rates in control versus GDM women, the results between both were similar, with rates of 35% and 69.44% respectively. The same data was corroborated in the study published by Zanrosso et al,[10] in which cesarean section was the delivery route adopted in 60.5% of the women with GDM.

We observe in our study a significant relationship between a prior cesarean section and the choice for surgical delivery in women with GDM (OR = 5.198, 95%CI = 2.702–10.003). Even today, the occurrence of a first cesarean section still determines a new cesarean section in the following pregnancy. Although some evidence shows benefits of vaginal delivery after cesarean section for most women with a previous cesarean section performed with a low transverse uterine incision, the fear of rupture of the uterine scar associated with the risk of fetal macrosomia leads to a surgical interruption of delivery in diabetic pregnant women.[16]

Gonçalves et al[17] showed a direct relationship between BMI and cesarean rates, especially in a group with BMI ≥ 30 kg/m2 (p = 0.004). These data corroborate those found in our study, in which the rates of cesarean delivery were significantly higher in women with GDM, especially when we analyzed those with a BMI of obesity (OR = 2.252, 95%CI = 1.493–3.396). Thus, it becomes evident that excessive gestational weight is a determining factor for the definition of the delivery route.

A study published by Landon et al[18] compared the perinatal outcomes in pregnant women with mild GDM. The results showed a significant reduction in cesarean rates among women with mild GDM treated pharmacologically compared with a control group (13.0% versus 19.7%, p = 0.01). It is known that GDM treatment reduces the frequency of fetuses large for gestational age, which may have contributed to the lower rate of cesarean sections.[18]

In our study, the type of treatment was not decisive for the choice of delivery route. Perhaps this difference in results may be linked to methodological issues, since our study lacked a control group for comparisons with other groups managed with pharmacotherapy or diet alone, considering that all pregnant women were treated.

The measurement of the FAC is a strong indicator of fetal overgrowth and hyperinsulinism,[20] with values ≥ 75% for gestational age measured between 29 and 33 weeks being closely related to fetal macrosomia.[21]

Due to the retrospective methodological design and the variability of professionals and individualized procedures in the referral center in which the data for this study were collected, we believe that controlled prospective studies may contribute to the credibility of the outcomes found in the present study.

Our study found a higher incidence of cesarean section than normal delivery in pregnant women with GDM.

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