INTRODUCTION — In pregnancies complicated by diabetes mellitus, a key therapeutic goal across gestation is avoidance of maternal hyperglycemia, which increases the risk of several pregnancy-specific adverse events, and hypoglycemia, which poses a risk to the mother. Good glycemic control remains important intrapartum because maternal hyperglycemia during labor increases the risk for fetal acidemia and neonatal hypoglycemia [1]. Postpartum, avoidance of hyperglycemia is less critical, but the risk for maternal hypoglycemia increases because of large, rapid changes in maternal hormone concentrations after delivery of the placenta.

It should be noted that intrapartum maternal normoglycemia will not reduce the risk of neonatal hypoglycemia in women with poor antepartum glycemic control, since fetal pancreatic hyperplasia and excessive in utero insulin secretion have been established in response to prolonged exposure to hyperglycemia. These neonates are at risk of developing severe and prolonged hypoglycemia. (See "Infants of women with diabetes", section on 'Hypoglycemia'.)

This topic will discuss intrapartum and postpartum glycemic control of women with pregestational (also called preexisting) and gestational diabetes. Other important issues in the management of these women are reviewed separately:

●(See "Pregestational (preexisting) diabetes: Preconception counseling, evaluation, and management".)

●(See "Pregestational (preexisting) diabetes mellitus: Antenatal glycemic control".)

●(See "Pregestational (preexisting) diabetes mellitus: Obstetric issues and management".)

●(See "Gestational diabetes mellitus: Glycemic control and maternal prognosis".)

●(See "Gestational diabetes mellitus: Obstetric issues and management".)

INTRAPARTUM GLUCOSE AND INSULIN REQUIREMENTS

Glucose

●Latent phase – Maternal metabolic demands are minimal during the latent phase. If oral intake is permitted, a reduced calorie diet (eg, 50 percent of daily caloric intake) will meet energy demands.

If oral intake is prohibited or severely restricted, maternal energy demands can usually be met over the short-term by metabolism of stored hepatic glycogen. As time in latent phase lengthens, glycogen stores will become depleted so an intravenous glucose-containing solution will be needed. Historically and not evidence based, a 5 percent dextrose normal saline intravenous solution at 125 mL/hour has been the standard, with a reduction in saline in women with vascular or cardiac disease or impaired renal function.

Labor induction often involves cervical ripening and a very long latent phase, adding additional time, glycemic monitoring, and fluid management. For women with intact membranes who are not in or approaching the active phase of labor by evening and do not have a maternal or fetal indication for delivery as soon as possible, the author prefers to stop cervical ripening agents/oxytocin at dinnertime, allow the patient a full dinner and overnight sleep, and then restart labor induction in the early morning. This preserves the mother's circadian rhythm and decreases fatigue from prolonged labor induction. However, restarting cervical ripening after dinner is also reasonable.

●Active phase – Active labor is an intense exercise with increased energy and hydration requirements. Most women, including those without diabetes, receive a 5 percent dextrose solution intravenously at 125 mL/hour, with adjustments based on maternal glucose levels, urine output, blood pressure, and specific comorbidities (eg, renal insufficiency, preeclampsia). We administer glucose infusions in women with diabetes via a pump separate from the "main line" containing a nonglucose solution so that when a nurse or anesthesiologist opens up the main line for a fluid bolus (eg, prior to initiating the epidural), the patient does not get flooded with glucose.

No trials have addressed the effects of intrapartum fluid management on women with pregestational or gestational diabetes, except with respect to neonatal outcomes (hypoglycemia, low pH). Glucose demands cannot be met by oral intake, since it is usually limited or prohibited during the active phase, and hepatic glycogen stores are rapidly depleted. Studies using glucose-controlled insulin infusion systems have shown that glucose requirements increase to approximately 2.5 mg/kg/minute to maintain maternal glucose concentration at 70 to 90 mg/dL (3.9 to 5 mmol/L) [2,3]. The total caloric requirement of labor cannot be met by a 5 percent dextrose infusion at any reasonable rate. The requirement is analogous to that observed with sustained and vigorous exercise. Intrapartum administration of glucose may also be important for optimal myometrial function.

Insulin — During both the latent and active phases of labor, women with type 2 and gestational diabetes generally produce sufficient endogenous insulin to maintain euglycemia without supplemental exogenous insulin.

Women with type 1 diabetes have no endogenous insulin production and therefore require exogenous basal insulin in the latent phase to maintain euglycemia and prevent diabetic ketoacidosis. In the active phase, insulin requirements are lower than in latent phase. Studies using glucose-controlled insulin infusion systems have shown that insulin requirements drop to almost zero in the active phase. (See 'Guidelines for insulin management' below.)

INTRAPARTUM MANAGEMENT — The changes in glucose and insulin requirements during labor mandate monitoring blood glucose concentration in women who have been treated with insulin or oral antihyperglycemic drugs during pregnancy. The frequency of monitoring depends on the phase of labor, diet, and whether exogenous insulin is being administered.

Glucose monitoring — Capillary blood glucose measurements are convenient and reasonably accurate over the normal range of blood glucose concentrations, but are more variable than venous measurements. In addition, each type of glucose meter has a manufacturer's limit of accuracy for a range of capillary blood glucose values; intrapartum capillary blood glucose values outside of these ranges should be confirmed by venous blood measurements, which can be tested first at the bedside with the glucose meter and then in the laboratory. However, overt hypoglycemia (<50 mg/dL [2.8 mmol/L]) or hyperglycemia (>180 mg/dL [10 mmol/L]) detected in capillary blood should be treated promptly, before confirmation has been obtained.

The optimum frequency of glucose monitoring required to maintain target glucose levels has not been established. Glycemic control depends on endogenous insulin secretion and insulin resistance; thus, closer monitoring is required in women with type 1 diabetes than in many women with type 2 or gestational diabetes.

●Pregestational diabetes – During the latent phase, we measure glucose levels every two to four hours in women with reduced oral intake and type 1 or type 2 diabetes, or diabetes diagnosed in early pregnancy (as these women are likely to have undiagnosed type 2 diabetes). If the woman is eating, we monitor capillary glucose levels before and after meals.

During the active phase, we measure glucose levels every hour in women receiving insulin supplementation either by infusion or subcutaneous injection.

●Gestational diabetes – Women with gestational diabetes who have maintained euglycemia antenatally on diet, lifestyle, and/or medical therapy rarely develop intrapartum hyperglycemia. A blood glucose level is measured on admission. During the latent phase, we monitor capillary glucose levels before and after meals in women who are eating. In the absence of significant oral intake, we check glucose levels no more frequently than every four to six hours, which is as efficacious as hourly assessment when the goal is to avoid neonatal hypoglycemia [4]. Monitoring frequency can be decreased in women with glucose values consistently within the target range. Women with glucose levels below or above target ranges should receive appropriate therapy and more frequent monitoring.

Continuous glucose monitoring — An increasing percentage of women with type 1 diabetes are using a continuous glucose measurement (CGM) system (and a continuous subcutaneous insulin infusion [CSII] system) throughout pregnancy. These systems link into smart phones and generate downloadable files. Importantly, CGM alerts the patient to impending hypoglycemia and hyperglycemia, allowing for glucose or insulin corrections to keep glucose levels in range. As hospitals develop the protocols and medical training for CGM and CSII, intrapartum glycemic monitoring and insulin administration should become simplified.

Prior to labor, a new CGM sensor (and CSII infusion set) should be moved to a site away from the lower abdomen (eg, to the outer upper hip or flank). If the hospital does not have a protocol for CGM systems, individualized orders should be written for the nursing service to monitor and record values with verification of low or high levels by standard monitoring procedures.

Glucose target — The ideal intrapartum target glucose level to reduce the risk of adverse neonatal hypoglycemia is not clear. Emerging data suggest that intrapartum glucose is not significantly associated with neonatal hypoglycemia requiring intravenous dextrose, after adjustment for large for gestational age, preterm delivery, and sex [5]. Secondary analysis of the CONCEPTT trial also found that neonatal hypoglycemia was not associated with intrapartum glucose levels but was associated with antenatal maternal glucose (higher second- and third-trimester glucose and cord C-peptide levels) and fetal hyperinsulinemia (greater large for gestational age birth weights and skinfold measures) [6].

In the absence of proven goals, a reasonable target range for intrapartum glucose levels is >70 and <126 mg/dL (>3.9 and <7.0 mmol/L), as this range has not been associated with clinically important neonatal hypoglycemia in insulin-requiring women (pregestational or gestational) [7-9]. This target range encompasses recommendations of both the American College of Obstetricians and Gynecologists (ACOG; 70 to 110 mg/dL [3.9 to 6.1 mmol/L]) [10] and the Endocrine Society Clinical Practice Guidelines (72 to 126 mg/dL [4 to 7 mmol/L]) [11]. Intrapartum glucose levels above 140 to 180 mg/dL (7.8 to 10.0 mmol/L) have been shown to be associated with neonatal hypoglycemia [12-14].

Although neonatal hypoglycemia may be a consequence of maternal intrapartum hyperglycemia, the most dangerous complication of intrapartum hyperglycemia is fetal hyperglycemia, which increases fetal oxygen requirements at a time when the ability of the placenta to provide an adequate supply of oxygen is compromised by uterine contractions. If intrapartum hyperglycemia occurs on a background of chronically poor maternal metabolic control (high glycated hemoglobin [A1C]), maternal hemoglobin will carry less oxygen, bind it more tightly, and therefore release it less well in areas of low oxygen tension, such as the intervillous space [15]. This can result in fetal hypoxemia and acidosis. Physiologically, macrosomic fetuses of women in chronically poor glycemic control will tolerate acute intrapartum maternal hyperglycemia less well than normally grown fetuses of women with chronically good glycemic control.

Guidelines for insulin management — Well-designed, sufficiently powered, randomized trials on intrapartum insulin management do not exist to guide recommendations for an optimal approach. Available evidence is largely retrospective or derived from groups of women with type 1, type 2, and gestational diabetes treated with the same protocol, thus not accounting for the wide differences in beta cell reserve and insulin resistance in women with different underlying metabolic disorders. Furthermore, most of the medical literature precedes the widespread use of the newer insulins, the use of oral agents, and continuous insulin infusion systems.

ACOG recommends intravenous insulin infusion for intrapartum glycemic management [10]. We individualize management, considering the woman's medical regimen prior to labor (eg, whether she used long-acting basal insulin with premeal rapid-acting insulin, combination dosing of intermediate- and rapid-acting insulin, or oral antihyperglycemic agents). The following approaches should not be considered absolute protocols. Clinicians managing women with diabetes who are in labor must be experienced in euglycemic medical management and be able to adjust regimens to meet changing intrapartum needs.

Women with pregestational diabetes using multiple daily insulin injections — For most women with pregestational diabetes using multiple daily insulin injections for control of blood glucose, the author prefers to use a subcutaneous insulin regimen for glucose control during labor. Euglycemia is maintained by giving one unit of subcutaneous rapid-acting insulin for each 20 mg/dL (1.1 mmol/L) increase in glucose above 120 mg/dL (6.6 mmol/L) (table 1). This scale works well for most laboring women who require insulin. Adjustments to the scale should consider the individual's degree of insulin resistance (eg, total daily insulin dose per kg) and the rapid-acting insulin correction factors used predelivery.

Infusion of intravenous insulin to maintain euglycemia during labor is another alternative to subcutaneous insulin and preferred for laboring women in poor glycemic control because it offers more rapid and better glycemic control than subcutaneous injection. This approach has been associated with low maternal and neonatal complication rates in women with type 1 diabetes [7,16,17] and can be used for women with type 2 or gestational diabetes requiring insulin. An example of an intrapartum regimen is provided in the table (table 1). Insulin is held as long as the glucose level is ≤120 mg/dL (6.7 mmol/L) [18]. Above this level, insulin infusion (units/hour) is begun and increased or decreased incrementally with increasing or decreasing maternal capillary blood glucose levels, which are measured hourly during insulin infusion [2,3,8,12,19-21]. Hypoglycemia is treated by administering an oral or intravenous dextrose infusion and decreasing the insulin infusion rate [10].

Women with pregestational diabetes on a continuous subcutaneous insulin infusion antepartum — Women with pregestational diabetes managed by CSII antepartum can continue use during labor induction and latent phase, decreasing the basal rate by 50 percent and administering bolus insulin doses, as needed, to correct hyperglycemia. During active labor, as insulin requirements rapidly drop, if the pump catheter becomes difficult to maintain, insulin administration, if needed, should be changed to continuous intravenous infusion (table 1) [22]. If the hospital does not have a protocol for the use of CSII, individualized orders should be written for the use of the CSII system and for basal, bolus, and correction insulin doses programmed into the pump for labor and postpartum. (See "Management of blood glucose in adults with type 1 diabetes mellitus", section on 'Continuous subcutaneous insulin infusion (insulin pump)'.)

The feasibility of this approach was supported by a multicenter retrospective study that reported successful glucose control (target range 70 to 140 mg/dL) with use of a standardized protocol for intrapartum CSII in a series of 65 women with type 1 diabetes [22]. The protocol involved setting up the pump with three different insulin basal rates and activating the most appropriate one, depending on the stage of labor and current glucose value, with correction boluses and intravenous glucose infusions, as needed. The three basal insulin rates were (1) the last antepartum level; (2) 30, 50, or 70 percent below the last antepartum level (based on whether the patient had a low, average, or high antepartum insulin requirement); and (3) 0.1 to 0.2 units/hour.

Women with gestational diabetes — For women with gestational diabetes, a strategy of "rotating fluids" (table 2) has been used as it decreases the need for insulin infusion. This approach should not be used in women with type 1 diabetes or type 2 diabetes with limited insulin secretion as they may develop ketoacidosis. A small randomized trial found similar mean glucose levels (103 mg/dL [5.7 mmol/L]) and neonatal outcomes in insulin-treated women (primarily gestational diabetes but some type 2 diabetes) who were treated with the rotating fluids protocol and those receiving continuous insulin drip to achieve glucose targets of 100 mg/dL (5.6 mmol/L) [18].

Special situations

Scheduled cesarean delivery

●Women receiving insulin – When cesarean delivery is planned in women with type 1 and type 2 diabetes, the procedure should be scheduled early in the morning. A patient on insulin therapy, either pregestational or gestational diabetes, should maintain her usual nighttime dose of intermediate-acting insulin, short- or rapid-acting insulin, oral antihyperglycemic medication, or continuous insulin infusion until admission to the hospital [19]. If she uses a long-acting basal insulin at night (detemir, glargine, or basaglar), the dose is decreased by 50 percent.

The morning dose of insulin or oral antihyperglycemic agent is held, and the patient is given nothing by mouth. In women with type 1 or type 2 diabetes controlled with intermediate-acting insulin (neutral protamine Hagedorn [NPH]), if surgery occurs later in the day, basal insulin (approximately one-third of the morning dose of NPH) is given with a 5 percent dextrose infusion in order to avoid ketosis.

Glucose levels should be monitored frequently, every one to three hours, with more frequent measurements in type 1 diabetes or if glucose levels are not in the target range; either intravenous insulin or subcutaneous rapid-acting insulin can be given, as needed, to control hyperglycemia during this period.

For intravenous prehydration before operative anesthesia, normal saline is used rather than a dextrose solution to avoid administering a large glucose bolus, which reduces umbilical cord pH and can cause neonatal hypoglycemia [23,24]. In women with diabetes, surgery in the early morning generally avoids the need for insulin.

Glucose levels should be monitored during the cesarean delivery if the operation lasts over an hour. Hyperglycemia during surgery should be avoided to minimize the risk of neonatal hypoglycemia, as well as maternal wound infection and metabolic complications.

Postoperative management is discussed below. (See 'Postpartum management' below.)

●Women with gestational diabetes managed with nutritional therapy alone – These women are managed similar to pregnant women without diabetes undergoing scheduled cesarean delivery. (See "Preoperative fasting in adults", section on 'Pregnant patients'.)

Induction of labor — Ideally, induction is scheduled for early morning. The patient should maintain her usual nighttime dose of intermediate-acting insulin, short- or rapid-acting insulin, oral antihyperglycemic medication, or continuous insulin infusion on the night before induction [19]. If she uses a long-acting insulin at night the dose needs to be decreased by 50 percent or switched to NPH insulin at one-third of the long-acting nightly dose.

The morning of induction, the author asks the woman to eat a light breakfast (half of her usual breakfast intake) and reduce her insulin dose (NPH and short- or rapid-acting insulin) by 50 percent. In women with continuous insulin infusion pumps, infusion is set at 50 percent of the basal rate, with bolus insulin doses based on grams of carbohydrate ingested.

Continued oral intake (at 50 percent of daily intake, 1000 to 1200 kcal) is permitted during cervical ripening/latent phase when this period is anticipated to exceed 8 to 12 hours and there is a low risk of emergency operative delivery (eg, reassuring fetal heart rate tracing, stable maternal condition).

Capillary blood glucose levels are measured pre- and postmeals and at bedtime, with administration of a rapid-acting insulin or bolus correction dose to achieve standard pregnancy goals for euglycemia pre- and postmeals. Alternatively, if subcutaneous insulin is not used, intravenous 5 percent dextrose infusion with intravenous infusion of short-acting insulin can be started and titrated every one to four hours to maintain blood glucose levels in the target range [10].

When labor becomes active, one of the protocols described above is initiated. (See 'Guidelines for insulin management' above.)

Guidelines for intrapartum management of women previously receiving oral antihyperglycemic agents — Metformin and glyburide are commonly used as primary treatment in pregnant women with gestational diabetes. Metformin is also used in conjunction with insulin in women with type 2 diabetes or gestational diabetes. If the woman will be fasting after midnight for a planned cesarean delivery or induction of labor, her nighttime dose of metformin or glyburide should be given and the morning dose withheld. (If extended-release metformin is used, she should take 50 percent of her nighttime dose.) If cervical ripening is planned and oral intake will be permitted during this process, she should take 50 percent of her morning dose of metformin or glyburide.

During labor, neither metformin nor glyburide should be given to control hyperglycemia.

POSTPARTUM MANAGEMENT — After delivery of the placenta, the insulin resistant state that characterizes pregnancy rapidly dissipates and insulin requirements drop precipitously. Glucose targets can be relaxed to avoid hypoglycemia from overtreatment.

Women with type 1 diabetes — Women with type 1 diabetes have markedly reduced insulin requirements for the first 24 to 48 hours after delivery and need frequent monitoring of glucose levels to avoid hypoglycemia. Postoperative patients should receive a 5 percent dextrose (0.45 normal saline) solution with no more than half of their basal insulin until adequate oral intake is resumed. Glucose levels should be checked every four to six hours and hyperglycemia treated with insulin prescribed using sliding scales. Similarly, patients on insulin pumps should have basal rates reduced by at least one-half and can administer correction doses via their pump using the prescribed sliding scale (table 3).

After approximately 24 to 48 hours, standard diabetes management can be resumed with calculated total daily dose of insulin at 0.6 units/kg postpartum weight or approximately 50 percent of the insulin dose prior to delivery. Marked hyperglycemia (eg, random glucose ≥180mg/dL [10.0 mmol/L]) should be avoided as hyperglycemia is associated with an increased risk of postoperative infection [25,26].

Women delivering vaginally generally resume normal oral intake after delivery. They can be restarted on their multiple daily dosing regimen but require one-third to one-half of their predelivery long-acting or intermediate-acting insulin dose to meet postpartum basal needs, and one-third to one-half of their predelivery short- or rapid-acting insulin premeal doses [10,19]. For women using insulin pumps, the basal insulin infusion should be reduced by approximately 50 percent [10], while the carbohydrate-to-insulin ratio and correction factor dosing generally returns to prepregnancy dose ranges. The goal is to maintain relaxed glucose levels and avoid hypoglycemia. For most patients, reasonable glycemic targets while hospitalized postpartum are premeal glucose concentrations <140 mg/dL (7.8 mmol/L) and random glucose concentrations <180 mg/dL (10 mmol/L).

Women with type 2 diabetes — Glucose levels tend to be normal or modestly elevated in postpartum women with type 2 diabetes. Fasting, pre- and postprandial glucose levels should be measured. Hyperglycemia is treated with insulin prescribed using a sliding scale (table 3). After 24 to 48 hours, the effects of pregnancy on glucose and endogenous insulin levels dissipate and standard diabetes management with diet and pharmacologic therapy should be resumed, as needed.

Metformin is the preferred first-line oral agent for type 2 diabetic patients and does not produce hypoglycemia. Intermediate-acting insulin in the AM and PM may also be needed. Early follow-up contact at two weeks postpartum to assess glucose control and insulin dose is helpful to adjust to the changing metabolic milieu during the puerperium. (See "Initial management of hyperglycemia in adults with type 2 diabetes mellitus" and "Metformin in the treatment of adults with type 2 diabetes mellitus".)

Women with gestational diabetes — Diabetes medications should be stopped after delivery in women with gestational diabetes.

Some authors, including this author, advocate assessing fasting glucose 24 to 72 hours after delivery to check for overt diabetes (fasting glucose ≥126 mg/dL [7.0 mmol/L]) [11]. If overt diabetes is not diagnosed while the patient is in the hospital after delivery, she should be screened or tested for diabetes 4 to 12 weeks after delivery to establish glucose status. Some authors have suggested performing a glucose tolerance test two days postpartum in circumstances in which postpartum follow-up is thought to be challenging, given that a majority of women do not return for postpartum diabetes screening and normal results are reliable for excluding type 2 diabetes [27]. Further follow-up is reviewed separately. (See "Gestational diabetes mellitus: Glycemic control and maternal prognosis", section on 'Follow-up'.)

Breastfeeding — Women with type 1, type 2, and gestational diabetes are strongly encouraged to breastfeed for its health benefits for mother and newborn. (See "Maternal and economic benefits of breastfeeding" and "Infant benefits of breastfeeding".)

Breastfeeding requires an additional 500 kcal per day, which can be consumed as 100 g of carbohydrate and 20 g of protein. Self-monitoring of glucose is important during the early postpartum period in women with type 1 or type 2 diabetes requiring insulin therapy. The frequency of glucose monitoring in women with type 2 diabetes on oral antihyperglycemic agents and breastfeeding is not established and should be guided by clinical judgment. Studies examining glucose control via continuous glucose monitoring in women with type 1 diabetes and established breastfeeding (eg, one to two months after delivery) suggest no increase in episodes of hypoglycemia compared with those artificially feeding [28] or matched, nonpregnant [29] women with type 1 diabetes.

There is minimal information on breast milk levels and infant effects of many antihyperglycemic agents. Insulin, glyburide, and metformin enter milk in small amounts that are unlikely to cause hypoglycemia; nevertheless, the infant should be observed for signs of low glucose levels if the mother is taking these drugs. The Drugs and Lactation Database of the US National Library of Medicine (LactMed) is an excellent, free, online resource for information on maternal and infant levels of drugs, possible effects on breastfed infants and on lactation, and alternate drugs to consider.

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Diabetes mellitus in pregnancy".)

INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5^th to 6^th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10^th to 12^th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.

Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)

●Basics topics (see "Patient education: Care during pregnancy for people with type 1 or type 2 diabetes (The Basics)")

●Beyond the Basics topics (see "Patient education: Care during pregnancy for women with type 1 or 2 diabetes (Beyond the Basics)")

SUMMARY AND RECOMMENDATIONS

●For women with diabetes, the key therapeutic goal during labor is to maintain euglycemia. Maternal hyperglycemia can increase the risk of fetal acidemia and neonatal hypoglycemia. (See 'Introduction' above.)

●Women with type 2 and gestational diabetes generally produce sufficient endogenous insulin and can maintain euglycemia during the latent phase of labor with minimal or no supplemental exogenous insulin. Women with type 1 diabetes have no endogenous insulin production and require exogenous basal insulin to maintain euglycemia and prevent diabetic ketoacidosis. During the active phase, exogenous insulin may not be needed because increased energy expenditure reduces insulin requirements to almost zero. (See 'Intrapartum glucose and insulin requirements' above.)

●For women with diabetes treated with insulin or antihyperglycemic drugs antepartum, a reasonable approach for intrapartum glucose monitoring is every two to four hours during the latent phase, every one to two hours during the active phase, and every hour when insulin is being infused. Women with gestational diabetes who have maintained euglycemia antenatally on diet, lifestyle, and/or medical therapy rarely develop intrapartum hyperglycemia; blood glucose levels may be measured on admission and then no more frequently than every four to six hours. Monitoring frequency can be decreased in women with glucose values consistently within the target range. If the woman is eating during latent phase, pre- and postprandial capillary glucose levels should be monitored. Women with glucose levels below or above target ranges should receive appropriate therapy and more frequent monitoring. (See 'Intrapartum management' above.)

●In absence of clear goals, a reasonable target range for intrapartum glucose levels is >70 and <126 mg/dL (>3.9 and <7.0 mmol/L), as a similar range has not been associated with clinically important neonatal hypoglycemia in insulin-requiring women. This range encompasses recommendations of both the American College of Obstetricians and Gynecologists and the Endocrine Society Clinical Practice Guidelines. Intrapartum glucose levels above 140 to 180 mg/dL (7.8 to 10.0 mmol/L) have been associated with neonatal hypoglycemia and an increased risk of maternal ketoacidosis in women with type 1 diabetes. (See 'Intrapartum management' above.)

●For women with type 1 or type 2 diabetes on a multiple daily insulin injection regimen, we suggest using subcutaneous insulin rather than intravenous insulin for intrapartum glycemic control (Grade 2C). Both strategies (table 1) are effective and have low complication rates. Women using insulin pumps may continue their use during labor and postpartum to administer basal insulin, adding prefeeding bolus doses and/or correction doses as needed. For women with gestational diabetes, rotating fluids between glucose-containing and nonglucose-containing fluids can help with glycemic control and minimize the need for insulin administration (table 2). (See 'Guidelines for insulin management' above.)

●Before scheduled early morning induction or cesarean delivery, the patient should maintain her usual nighttime dose of intermediate-acting insulin, short- or rapid-acting insulin, oral antihyperglycemic medication, or continuous insulin infusion. Women controlled on long-acting basal insulin should take 50 percent of their nighttime dose. On the morning of cesarean delivery, the morning dose of insulin or oral antihyperglycemic agent is held, and the patient is given nothing by mouth. On the morning of induction, the woman eats a light breakfast and reduces her insulin dose (NPH and short- or rapid-acting insulin or metformin), generally by 50 percent. Continuous insulin infusion pumps are set at approximately 50 percent of the basal rate with bolus insulin based on carbohydrate exchanges. (See 'Special situations' above.)

●After delivery of the placenta, the insulin resistant state that characterizes pregnancy rapidly disappears. Women with type 1 diabetes need close glucose monitoring to avoid hypoglycemia since insulin requirements drop precipitously. Women with type 2 diabetes may have normal to elevated glucose levels during the first 24 to 48 hours postpartum and may not need any antihyperglycemic therapy. Women with gestational diabetes can have fasting glucose levels monitored for 24 to 72 hours after delivery to check for diabetes (fasting ≥126 mg/dL [7.0 mmol/L]). Unless overt diabetes is diagnosed postpartum, women with gestational diabetes should be screened or tested for diabetes 4 to 12 weeks after delivery to establish glucose status. (See 'Postpartum management' above.)

ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Michael F Greene, MD, who contributed to an earlier version of this topic review.