Introduction

The prevalence of gestational diabetes mellitus (GDM) is rapidly increasing across the world and it is a common endocrine complication in obstetric practice today [1–3]. GDM, as a syndrome, is marked by controversy related to virtually every facet, ranging from its nomenclature, screening tools, and diagnosis to management strategies [4, 5]. Most debate on GDM management centers on medical issues, such as appropriateness of oral hypoglycemic agents. In this communication, we discuss the timing of delivery in GDM and emphasize the need for person-centered, shared decision-making in this regard.

Compliance with Ethics Guidelines

This article does not contain any new studies with human or animal subjects performed by any of the authors.

Current Recommendations

Expert recommendations suggest that women with uncomplicated GDM take their pregnancies to term, and deliver at 38 weeks gestation [6]. Such a decision is not as simple as it seems. These recommendations differ from earlier findings, which suggested earlier induction of labor [7], but are consonant with secular trends in obstetrics, which support longer periods of gestation. Guidelines also state that GDM per se is not a factor in determining mode of delivery [6, 8].

The American College of Obstetricians and Gynecologists and the Society for Maternal Fetal Medicine have proposed new recommendations for terminology of gestational age and delivery timing [6]. For women with well-controlled diabetes, whether pregestational or gestational, a late preterm or early term birth, i.e., before 39 completed weeks of gestation, is not indicated. In a setting of poorly controlled diabetes, an individualized decision aiming for late preterm or early term delivery (before 38 weeks + 6 days gestation) is recommended. An early term or term delivery (38–39 weeks + 6 days gestation) is suggested if vascular complications are present in women with pregestational diabetes. In practice, however, these gestational ages may be difficult to attain. It must also be remembered that these recommendations assume 24/7 availability, accessibility, and affordability of optimal maternal and fetal monitoring, including seven-point glycemic profiles and regular cardiotocography for all women with GDM. They also take certain attributes of physical environment, such as ease of travel and communication, for granted.

Person-Specific Attributes of GDM

GDM, however, is not a homogenous entity. Each woman with GDM faces unique challenges with respect to her ethnicity, biomedical condition, psychological makeup, and social support system [9]. These factors influence postpartum health as well [10]. All these factors may potentially impact obstetric decision-making. While robust guidelines are available to help such decision-making [6, 11], the quality of many guidelines needs to be improved. There is discrepancy regarding induction of labor [12]. There is, therefore, a need to revisit the factors which may determine the timing of delivery. These obstetric, biomedical, and psychosocial factors influence the course of pregnancy complicated by diabetes and inform decision-making related to mode and timing of delivery (Table 1). We highlight some of these factors in the following paragraphs.

Table 1 Factors influencing timing of delivery in GDM
Full size table

Biomedical Factors

The obstetrician considers many obstetric and medical factors while planning the delivery in a woman with GDM. These are listed in Table 1. Some of these factors play a role in decision-making for all deliveries, irrespective of the presence of diabetes. Certain issues, however, merit greater attention in women with GDM.

In general, waiting at least until 38 completed weeks’ gestation improves fetal outcome, especially in diabetic patients [13]. However, if an indication for early delivery exists, GDM should not be considered as a contraindication to proceed with interventions for early delivery. Also, if a spontaneous preterm delivery seems imminent, it should not be postponed [14]. At times, in fact, an early, planned operative delivery may be appropriate for women with ketosis or ketoacidosis [15], difficult-to-control diabetes, with frequent episodes of hypoglycemia or hyperglycemia, excessively high insulin requirements, or any other clinical situation which may put the fetus at risk [16]. This may also be true for women with compromised cardiovascular, renal, or retinal function.

Macrosomia is a common accompaniment of GDM, especially in women with uncontrolled glycemia [16]. The risk of cephalopelvic disproportion (CPD) and shoulder dystocia increases as fetal weight gain occurs with advancing gestational age. The chances of a normal vaginal delivery, therefore, may recede as gestation progresses in women with refractory GDM, or in women on excessively high doses of insulin. In non-diabetic women, induction of labor for suspected macrosomia, at 39 weeks gestation, has been found to be cost-effective [17] in reducing maternal complications.

Psychosocial Factors

This issue is important in cultures where a premium is placed upon a woman’s ability to have normal childbirth, where the parturient is unable to afford the physical rest required after surgical delivery, or if the financial burden associated with an operative delivery has to be paid by the patient. These realities imply that an earlier, planned delivery, at 36–37 weeks gestation, may be indicated in select women with GDM, who wish to try and maximize the chances of a normal vaginal delivery. Induction of labor at less than 40 weeks gestation in women with mild GDM does not increase the risk of LSCS [18]. In fact, the risk of LSCS rises threefold in women who are induced at 41 weeks, as compared to those who are induced at 39 weeks [18].

Environmental Factors

Apart from the psychosocial factors discussed above, other external determinants play a role in deciding the timing of delivery. Availability of medical support (needed to manage glycemia after antenatal corticosteroid (ACS) therapy), of facilities and expertise for assisted vaginal delivery (ventouse, forceps), of facilities for operative delivery (including anesthesiology), and of neonatal care influence the choice of timing and mode of delivery. Lack of neonatology or medicine expertise supports a decision to continue women with GDM to term, rather than risk a clinical situation where the mother, with iatrogenic hyperglycemia secondary to ACS, or the preterm neonate, delivered by induced labor, cannot be managed.

The distance that a woman with GDM has to travel to access health care, the ease with which the journey is negotiated, and the feasibility of regular frequent follow-up also influence the mode and timing of delivery. Early induction of labor may be appropriate for women who find it difficult or expensive to travel repeatedly to the health-care center, for whom travel is uncomfortable or fraught with physical risk, or who are unable to adhere to the recommended frequency of follow-up. While we understand that these scenarios may seem implausible to many readers, they are the reality for people living with diabetes in many parts of the world [19, 20].

Shared Decision-Making

Decision regarding the mode and timing of delivery is a major challenge in routine obstetric care. This is especially true for women with GDM. The nature of the condition is such that it is challenging to conduct randomized controlled trials to assess the impact of the mode and timing of delivery on fetomaternal health. One must rely upon observational data, experience, and “good clinical sense” to decide the optimal method of delivery. The biopsychosocial model [21], coupled with shared decision-making, provides a useful framework to help solve this clinical dilemma.

The patient, and her family, including husband and mother-in-law [20], should be counseled about the potential benefits and harms of early (prior to 39 weeks gestation) and delayed delivery. Her views and preferences must be ascertained and appropriate decisions taken. Input from other medical professionals, who are an integral part of the GDM care team, should also be considered. Anticipated baby weight and placental maturity, determined by the radiologist; Bishop’s score, calculated by the obstetrician or midwife; maternal and family attitudes towards caesarian section, ascertained by the diabetes educator or psychologist; and suitability or risk stratification for anesthesia must all be taken into account while planning the time of delivery (Table 1).

It must be remembered, though, that in all decision-making, maternal and fetal safety come first. Shared decision-making can be considered in situations characterized by clinical equipoise, where more than one therapeutic option is available [22]. For example, a woman with GDM, with a good sized baby (>4000 g weight) [23]) on abdominal or ultrasonographic examination, presenting at 37–38 weeks with a history of recent weight gain, and favorable cervical findings on per vaginum examination may be given the option of induction of labor. On the other hand, a scenario with maternal distress or fetal distress leaves no room for prevarication: informed consent for labor induction is absolutely necessary to ensure maternal and fetal well-being.

Conclusion

The timing of delivery in GDM is an important decision, which should be taken keeping in mind the biomedical, psychological, social, and environmental factors operating in the particular person. Such a decision is best arrived at through a process of active, informed discussion with the patient and her family.