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Gestational Diabetes Mellitus (GDM)
Glucose intolerance that develops during pregnancy — screened at 24–28 weeks.
Screening & Diagnosis
- 1-hour glucose challenge (50g): If ≥140 mg/dL → proceed to 3-hour GTT
- 3-hour GTT (100g): 2 or more abnormal values = GDM diagnosis
Blood Glucose Targets
- Fasting
- <95 mg/dL
- 1-hour postprandial
- <140 mg/dL
- 2-hour postprandial
- <120 mg/dL
Management
- Diet: Controlled carbohydrate intake, small frequent meals (3 meals + 2–3 snacks), complex carbs over simple sugars, bedtime snack (prevents overnight hypoglycemia)
- Exercise: 30 min/day moderate activity (walking)
- Insulin: If diet/exercise fail. Does NOT cross the placenta (safe for fetus).
- Oral agents: Glyburide or metformin may be used in some cases
- Monitor blood glucose: 4x/day (fasting + after each meal)
Risks
- Fetal: Macrosomia (large baby >4,000g → shoulder dystocia risk), neonatal hypoglycemia, respiratory distress, jaundice, polycythemia
- Maternal: Preeclampsia, polyhydramnios, C-section, increased risk of type 2 DM later in life
- After delivery → glucose usually normalizes. Screen for type 2 DM at 6–12 weeks postpartum.
Infant of Diabetic Mother (IDM)
The baby of a GDM mother is at risk for neonatal hypoglycemia immediately after birth. In utero, the fetus produced extra insulin to handle mom's high glucose. After delivery, mom's glucose is gone but the baby's insulin is still high → blood sugar drops. Monitor glucose within 1 hour of birth and feed early.
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02
Hypertensive Disorders of Pregnancy
The most tested OB complication — know the progression from gestational HTN to eclampsia.
- Gestational HTN≥140/90, no proteinuria
- BP elevation only. No end-organ damage. Resolves by 12 weeks postpartum.
- Preeclampsia≥140/90 + proteinuria
- HTN + proteinuria (≥300 mg/24h). Headache, visual changes, facial/hand edema, hyperreflexia, epigastric pain, elevated liver enzymes.
- Severe Preeclampsia≥160/110
- All above + severe symptoms. Oliguria, pulmonary edema, thrombocytopenia, elevated creatinine.
- Eclampsiapreeclampsia + seizures
- Preeclampsia + SEIZURES. Life-threatening emergency. Can occur before, during, or after delivery.
Preeclampsia Management
- Magnesium sulfate IV — prevents seizures (#1 drug). Does NOT lower BP.
- Antihypertensives: Labetalol IV or hydralazine IV for acute BP reduction. Methyldopa or nifedipine PO for maintenance.
- The ONLY cure is delivery — delivery of the baby AND placenta
- Seizure precautions: Dim lights, quiet room, pad side rails, suction at bedside, no visitors
- Monitor: VS q15–30 min, I&O (UO ≥30 mL/hr), DTRs, LOC, FHR
- Assess for clonus (rhythmic dorsiflexion at ankle) — indicates CNS irritability, seizure risk
If Seizure (Eclampsia) Occurs
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Stay with the patient — call for help
2
Turn to side (prevent aspiration)
3
Do NOT restrain or put anything in the mouth
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Administer magnesium sulfate bolus (if not already on it)
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Administer oxygen
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Monitor FHR after seizure
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Prepare for emergency delivery
Mag Sulfate — Assess Before Every Dose
Before giving ANY dose of magnesium sulfate, check: DTRs (must be present — absent DTRs = first sign of toxicity), respiratory rate (must be ≥12), and urine output (must be ≥30 mL/hr). Antidote: calcium gluconate — must be at bedside at ALL times.
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HELLP Syndrome
A life-threatening variant of severe preeclampsia — the name tells you the labs.
- H — Hemolysis (RBCs breaking down → elevated LDH, schistocytes on smear)
- EL — Elevated Liver enzymes (AST, ALT → liver damage)
- LP — Low Platelets (<100,000 → bleeding risk)
Signs & Symptoms
- RUQ or epigastric pain (liver capsule distension)
- Nausea/vomiting
- Malaise, flu-like symptoms
- May or may not have HTN or significant proteinuria (can be subtle)
Management
- Delivery — definitive treatment (regardless of gestational age if severe)
- Magnesium sulfate (seizure prevention)
- Corticosteroids for fetal lung maturity if <34 weeks
- Monitor for DIC (coagulopathy), liver rupture, placental abruption
- Prepare for possible blood transfusion (low platelets + hemolysis)
Epigastric Pain in a Pregnant Patient
If a question describes a pregnant patient with epigastric or RUQ pain + elevated BP + headache → think HELLP syndrome or severe preeclampsia with liver involvement. This is NOT heartburn. This is a medical emergency requiring immediate lab work and preparation for delivery.
04
Placenta Previa vs Placental Abruption
The #1 most tested comparison in OB nursing — know every difference.
- Definition
- Previa: Placenta implants over or near the cervical os. Abruption: Placenta separates prematurely from uterine wall.
- Bleeding
- Previa: Bright red, painless. Abruption: Dark red, painful (may be concealed).
- Pain
- Previa: None. Abruption: Severe — sudden onset, constant.
- Uterus
- Previa: Soft, relaxed, non-tender. Abruption: Rigid, board-like, tender.
- Risk factors
- Previa: Prior C-section, multiple pregnancies, prior previa, smoking. Abruption: HTN/preeclampsia, abdominal trauma, cocaine use, prior abruption.
- Vaginal exam?
- Previa: NEVER (can cause massive hemorrhage). Abruption: May be done carefully.
- Delivery
- Previa: C-section (placenta is blocking the exit). Abruption: Vaginal if mild, emergency C-section if severe.
Previa = NO Vaginal Exam
If a patient has placenta previa → absolutely NO vaginal exams, no intercourse, no douching. Inserting anything into the vagina can rupture the placenta and cause fatal hemorrhage. If a question describes painless bright red bleeding in the 3rd trimester → think previa → NO vaginal exam.
? A patient has sudden painful dark red bleeding and a board-like uterus — previa or abruption?
Placental abruption — the triad of painful bleeding + rigid/board-like uterus is abruption. Previa causes painless bright red bleeding with a soft, relaxed uterus.
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Ectopic Pregnancy
Implantation outside the uterus — most commonly in the fallopian tube.
- Location: ~95% occur in the fallopian tube (tubal pregnancy)
- Risk factors: Prior ectopic, PID, tubal surgery, IUD, endometriosis, smoking
- Signs: Unilateral lower abdominal pain, vaginal spotting, missed period, positive hCG (but lower than expected for gestational age), shoulder pain (referred pain from blood irritating diaphragm = ruptured ectopic)
- Ruptured ectopic: Surgical emergency — signs of hemorrhagic shock (tachycardia, hypotension, acute abdomen)
- Treatment: Methotrexate (if unruptured, small, stable) — folic acid antagonist that stops cell growth. Or surgical removal (salpingectomy/salpingostomy).
- After methotrexate: Monitor serial hCG until 0. Avoid alcohol, folate supplements, NSAIDs, and sexual intercourse during treatment. Avoid pregnancy for 3 months.
- RhoGAM if mother is Rh-negative
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Rh Incompatibility
Rh-negative mother + Rh-positive baby = risk of hemolytic disease of the newborn.
- The problem: If fetal Rh-positive blood enters the Rh-negative mother's circulation → she makes anti-Rh antibodies → these antibodies cross the placenta in FUTURE pregnancies → attack Rh-positive fetal RBCs → erythroblastosis fetalis (hemolytic disease of the newborn)
- First pregnancy: Usually not affected (sensitization occurs during delivery)
- Prevention: RhoGAM (Rh immune globulin)
RhoGAM Timing
- 28 weeks gestation (routine)
- Within 72 hours postpartum if baby is Rh-positive
- After ANY sensitizing event: miscarriage, abortion, ectopic, amniocentesis, CVS, abdominal trauma, placental abruption
- Given IM to the MOTHER (not the baby)
- Indirect Coombs test must be NEGATIVE (if positive → already sensitized → RhoGAM won't help)
RhoGAM NOT Needed If...
The baby is Rh-NEGATIVE (no incompatibility exists), or the mother is Rh-POSITIVE (she already has the Rh antigen), or the indirect Coombs is POSITIVE (already sensitized — too late). RhoGAM only helps PREVENT sensitization, it cannot reverse it.
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PROM & PPROM
Membranes rupture before labor — timing determines management.
- PROM≥37 weeks, before labor
- Usually induce labor within 12–24 hours if labor doesn't start spontaneously (infection risk increases with time). Monitor for chorioamnionitis.
- PPROM<37 weeks, before labor
- If <34 weeks: expectant management (bed rest, antibiotics to prolong pregnancy, corticosteroids for fetal lungs, monitor for infection). If ≥34 weeks: may induce.
Signs of Chorioamnionitis (Infection)
- Maternal fever ≥100.4°F
- Maternal and fetal tachycardia
- Foul-smelling amniotic fluid
- Uterine tenderness
- If chorioamnionitis develops → delivery regardless of gestational age + IV antibiotics
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Preterm Labor
Regular contractions with cervical change between 20–37 weeks.
Signs of Preterm Labor
- Regular contractions (≥4 per hour)
- Menstrual-like cramping, low back pain, pelvic pressure
- Change in vaginal discharge (mucus plug, pink-tinged, watery)
- Cervical dilation or effacement
Management — Buy 48 Hours for Steroids
- Tocolytics — suppress contractions to buy time (NOT a long-term solution)
- Terbutaline (beta-2 agonist): tachycardia, tremors, hyperglycemia
- Nifedipine (CCB): hypotension — do NOT combine with mag sulfate
- Indomethacin (NSAID): only <32 weeks (ductus arteriosus closure risk)
- Betamethasone IM — 2 doses, 24 hours apart. Promotes fetal lung maturity (surfactant). Most effective 24–34 weeks. Takes 24–48 hours to work.
- Magnesium sulfate — neuroprotection for fetus if <32 weeks (reduces cerebral palsy risk)
- GBS prophylaxis — if GBS status unknown or positive → IV penicillin during labor
- Fetal fibronectin test — if NEGATIVE, very unlikely to deliver within 2 weeks (high negative predictive value)
Preterm Labor Triad
If a question describes a patient at 28 weeks in preterm labor → expect 3 medications: 1) Tocolytic (stop contractions), 2) Betamethasone (fetal lung maturity), 3) Magnesium sulfate (fetal neuroprotection if <32 wks). These three are almost always ordered together.
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Hyperemesis Gravidarum
Severe, persistent vomiting beyond normal morning sickness — can be dangerous.
- Different from normal morning sickness: Persistent vomiting that leads to dehydration, weight loss (>5% of pre-pregnancy weight), electrolyte imbalances, ketonuria
- Complications: Dehydration, metabolic alkalosis (losing HCl from stomach acid), hypokalemia, hyponatremia, malnutrition, Wernicke encephalopathy (thiamine deficiency)
- Treatment:
- IV fluids (NS or LR) for rehydration
- Electrolyte replacement (especially potassium)
- Antiemetics: ondansetron (Zofran), promethazine, metoclopramide
- Thiamine (B1) supplementation (prevent Wernicke's)
- NPO initially → advance diet slowly (dry crackers, bland foods)
- Small frequent meals when tolerating PO
- TPN if severe and prolonged
- Monitoring: Daily weights, I&O, electrolytes, ketones in urine
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Frequently Asked Questions
Common student questions on this topic.
What is the difference between preeclampsia and eclampsia?
Preeclampsia is new-onset hypertension (≥140/90) plus proteinuria after 20 weeks of pregnancy. Severe features include BP ≥160/110, severe headache, vision changes, RUQ pain, thrombocytopenia, elevated liver enzymes. Eclampsia is preeclampsia plus seizures. Treatment: magnesium sulfate for seizure prevention/treatment, antihypertensives, deliver the baby when safe. Calcium gluconate is the antidote for magnesium toxicity.
What is HELLP syndrome?
HELLP is a severe form of preeclampsia involving: Hemolysis, Elevated Liver enzymes, Low Platelets. Symptoms include RUQ or epigastric pain, nausea/vomiting, malaise, headache. It can occur without classic preeclampsia signs. Definitive treatment is delivery. Maternal complications include DIC, liver rupture, abruptio placentae; perinatal mortality is high. Stabilize with magnesium and antihypertensives until delivery.
What is the difference between placenta previa and abruptio placentae?
Placenta previa = placenta implants over or near the cervical os. Causes painless bright red bleeding in the second/third trimester. No vaginal exams! Diagnose with ultrasound. C-section if complete previa. Abruptio placentae = premature separation of a normally implanted placenta. Causes painful dark red bleeding (or concealed bleeding), rigid uterus, fetal distress. Emergency delivery often needed. Risk factors: hypertension, cocaine use, trauma.
What is gestational diabetes and how is it managed?
Gestational diabetes mellitus (GDM) is glucose intolerance first identified during pregnancy. Screened at 24–28 weeks (1-hour GTT, follow with 3-hour if positive). Increases risk of macrosomia, shoulder dystocia, neonatal hypoglycemia, preeclampsia. Management: diet + exercise first; if uncontrolled, insulin (oral hypoglycemics like glyburide may also be used). Glucose checks 4×/day. Most resolve postpartum, but about half later develop type 2 diabetes, so lifelong screening is important.
What are the signs and symptoms of an ectopic pregnancy?
Ectopic pregnancy = implantation outside the uterus, usually in the fallopian tube. Classic triad: missed period, unilateral abdominal/pelvic pain, vaginal bleeding. If ruptured: severe sudden pain, shoulder pain (referred from diaphragm irritation), signs of hypovolemic shock. Surgical emergency. Risk factors: history of pelvic inflammatory disease, prior ectopic, IUD, tubal surgery, smoking. Treatment: methotrexate (early) or surgery.
What is preterm labor and how is it managed?
Preterm labor = regular contractions causing cervical change before 37 weeks. Signs: regular contractions (> 4/hour), low backache, pelvic pressure, vaginal bleeding, leaking fluid. Management: tocolytics (magnesium sulfate, terbutaline, nifedipine) to delay labor 48 hours, allowing corticosteroids (betamethasone) to mature fetal lungs. Magnesium sulfate also provides neuroprotection < 32 weeks. Bed rest, hydration, treat any underlying infection.
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