Gestational Diabetes Mellitus

Also known as: GDM

Carbohydrate intolerance first recognized in pregnancy, driven by progressive insulin resistance from placental hormones (human placental lactogen, progesterone, cortisol) unmasking limited maternal pancreatic reserve.

Risk factors include obesity (BMI ≥30), previous GDM, a previous macrosomic baby (over 4.5 kg), family history of diabetes, South Asian, Black, or Middle Eastern ethnicity, PCOS, and previous unexplained stillbirth.

75 g OGTT at 24 to 28 weeks for at-risk women (or universal screening per local protocol), performed as soon as identified if there is a history of previous GDM
Diagnostic thresholds (WHO/IADPSG): fasting glucose ≥5.1 mmol/L, 1-hour ≥10.0 mmol/L, or 2-hour ≥8.5 mmol/L, any single value meeting or exceeding the threshold confirms diagnosis (NICE uses slightly different cutoffs: fasting ≥5.6 mmol/L, 2-hour ≥7.8 mmol/L)

First line: dietary modification (carbohydrate counting or low glycemic index approach) and exercise, with self-monitoring of capillary glucose; targets: fasting under 5.3 mmol/L, 1-hour postprandial under 7.8 mmol/L, 2-hour postprandial under 6.4 to 6.7 mmol/L
If targets are not met within 1 to 2 weeks of lifestyle measures: metformin 500 mg PO od, titrated up to 500 mg to 1 g bd-tds (maximum 2 to 2.5 g/day)
Insulin added or substituted where metformin is insufficient, not tolerated, or contraindicated, typically basal-bolus or intermediate-acting regimens, with doses individualized and reviewed frequently given rapidly changing insulin requirements through pregnancy
Glibenclamide (glyburide) is used as an alternative oral agent in some settings, though generally less preferred given evidence of higher rates of neonatal hypoglycemia and macrosomia compared with insulin or metformin
Fetal surveillance: growth scans every 4 weeks from around 28 to 36 weeks
Timing of delivery: by 40+6 weeks if diet-controlled and uncomplicated; earlier (37 to 39 weeks) if on pharmacological therapy or complications are present, per local protocol
Postpartum: stop hypoglycemic agents at delivery; 75 g OGTT at 6 to 13 weeks postpartum to exclude persistent diabetes, and annual HbA1c thereafter given a roughly 50% ten-year risk of progression to type 2 diabetes

Referral: joint diabetes-obstetric antenatal clinic for all confirmed GDM.

Clinical toolsCalculators

BMI GCS EDD Parkland Formula

Corrected Sodium Corrected Calcium Anion Gap Creatinine Clearance Insulin Calculations qSOFA Wells PE Wells DVT CHA₂DS₂-VASc HAS-BLED CURB-65 Centor/McIsaac

Intrauterine Fetal Death

Also known as: IUFD, Stillbirth

Death of the fetus in utero before delivery, most commonly used to describe death from 24 weeks gestation onward (stillbirth, definitions of the specific gestational threshold vary by country), distinguished from earlier pregnancy loss (miscarriage, see that entry).

Causes include placental insufficiency and FGR, placental abruption, cord accident, congenital anomaly, infection, maternal medical conditions (diabetes, hypertension, obstetric cholestasis), and, in a substantial proportion, no cause is identified despite thorough investigation.

Breaking the news requires sensitivity, clarity, and time, delivered by an experienced clinician in a private setting, with the woman's partner or support person present where possible
Investigation for cause, offered but not mandatory, and tailored to maternal preference: maternal bloods (FBC, coagulation profile given DIC risk with retained dead fetus, HbA1c, thyroid function, Kleihauer test, maternal infection screen, thrombophilia screen where indicated, antibody screen), placental and fetal examination (with parental consent), and, where accepted, postmortem examination, which remains the single most informative investigation where consent is given
Mode of delivery: vaginal birth is generally recommended as the preferred mode in the absence of a specific contraindication (previous classical cesarean, placenta praevia), given the lower maternal morbidity compared with cesarean; induction with mifepristone 200 mg PO followed 24 to 48 hours later by misoprostol (dose and route per local protocol, commonly vaginal or oral, repeated at intervals) is standard, with dosing adjusted downward for a previous cesarean scar given rupture risk
Coagulopathy risk (from thromboplastin release with prolonged fetal retention) increases with time since death, and coagulation should be monitored, particularly if delivery is delayed beyond 2 to 3 weeks from confirmed death
Anti-D prophylaxis for Rh negative women
Lactation suppression counseling and, if desired, pharmacological suppression (cabergoline 1 mg PO single dose, given within the first days postpartum) offered
Bereavement support, memory-making opportunities (holding the baby, photographs, mementos) offered per parental wishes, and referral to bereavement counseling and support services
Future pregnancy counseling: discussion of recurrence risk (generally low if no specific cause identified, higher with an identified recurrent risk factor such as antiphospholipid syndrome), and a plan for increased surveillance in a subsequent pregnancy

Referral: obstetric-led care throughout; bereavement support and counseling services; genetics or maternal-fetal medicine input where a specific recurrent cause is identified.

Gestational Diabetes Mellitus

Overview

Clinical Features

Diagnosis

Management

Overview

Clinical Features

Diagnosis

Management