Gestational Diabetes Screening
Universal screening at 24–28 weeks gestation with 50 g 1-hr glucose challenge test (GCT); if ≥ 140 mg/dL, confirm with diagnostic 100 g 3-hr oral glucose tolerance test (OGTT).
RhoGAM Administration
Administer 300 μg anti-D immune globulin to Rh-negative unsensitized mothers at 28 weeks gestation and within 72 hours of delivery of an Rh-positive newborn.
Preterm Labor Tocolysis
At 24–34 weeks: Antenatal corticosteroids (Betamethasone × 2 doses) for fetal lung maturity + Tocolysis (Indomethacin < 32 wks, Nifedipine 32–34 wks) + Magnesium sulfate for neuroprotection.
Cervical Insufficiency
Painless second-trimester cervical dilation without contractions; history of prior pregnancy loss; transvaginal ultrasound cervical length < 25 mm; treat with cervical cerclage.
Gestational Diabetes & Rh Alloimmunization Protocols
| Clinical Entity | Screening Timing & Diagnostic Criteria | Fetal & Maternal Risks | Evidence-Based Management |
|---|---|---|---|
| Gestational Diabetes Mellitus (GDM) | Screen at 24–28 weeks: 50 g 1-hr screen (≥ 140 mg/dL abnormal); Confirm: 100 g 3-hr OGTT (≥ 2 abnormal: Fasting ≥ 95, 1-hr ≥ 180, 2-hr ≥ 155, 3-hr ≥ 140) | Fetal macrosomia (> 4,500 g), shoulder dystocia, neonatal hypoglycemia, polycythemia, hyperbilirubinemia, respiratory distress syndrome | First-line: Diabetic nutritional counseling and exercise; Pharmacotherapy: Insulin (first-line agent; does not cross placenta); Metformin or Glyburide if insulin declined |
| Rh (D) Alloimmunization | Initial prenatal visit: Maternal ABO/Rh type and antibody screen; Unsensitized Rh-negative: Anti-D antibody titer negative | Anti-D IgG crosses placenta → fetal hemolysis → severe anemia → high-output heart failure → Erythroblastosis fetalis / Hydrops fetalis | Anti-D Immune Globulin (RhoGAM 300 μg): 1. At 28 weeks gestation, 2. Within 72 hours of delivery of Rh+ infant, 3. Following any bleeding event, amniocentesis, or trauma; Kleihauer-Betke test guides postpartum dose |
Preterm Labor Master Algorithm (< 37 Weeks)
| Gestational Age | Mandatory Interventions | Tocolytic of Choice | Target Physiologic Outcome |
|---|---|---|---|
| < 32 Weeks Gestation | Betamethasone (IM × 2 doses 24 hrs apart) + Magnesium Sulfate (IV load then infusion) + Ampicillin/Penicillin (GBS prophylaxis) | Indomethacin (COX inhibitor; first-line < 32 wks; limit to 48 hours to prevent premature ductus arteriosus closure and oligohydramnios) | Lung maturity (surfactant), fetal cerebral palsy reduction (neuroprotection via MgSO4), GBS sepsis prevention |
| 32 to 34 Weeks Gestation | Betamethasone + GBS chemoprophylaxis | Nifedipine (oral calcium channel blocker; smooth muscle relaxation; watch maternal hypotension) | Accelerate pulmonary pneumocyte type II surfactant production |
| 34 to 36 6/7 Weeks (Late Preterm) | Betamethasone single course (if not previously given) + GBS prophylaxis if indicated | Tocolysis generally NOT recommended unless delivery delayed for maternal transfer | Reduce neonatal respiratory morbidity |
OMM Board Correlate: Pelvic Mechanics & Uterine Autonomics
- Uterine Autonomics: Sympathetics originate from T10–L2 (inferior mesenteric and hypogastric plexuses); parasympathetics from S2–S4 via pelvic splanchnics. Hyperactive sympathetics lead to uterine vasoconstriction and hypertonic dysfunction.
- Sacral Rocking: Gentle sacral rocking normalizes parasympathetic outflow to the uterus and cervix. In pregnancy, release of the round ligaments (attaching uterus through inguinal canal to labia majora) relieves lower abdominal and groin ache.
- HVLA Safety: HVLA thrust on the pregnant lumbar spine or pelvis is contraindicated in the presence of acute antepartum hemorrhage, placenta previa, or preeclampsia.
Board Traps & Common Distractors
- Indomethacin must NOT be used as a tocolytic beyond 32 weeks gestation or for longer than 48 hours due to the danger of premature in utero closure of the ductus arteriosus and fetal oligohydramnios.
- In patients receiving Magnesium sulfate for preterm neuroprotection or preeclampsia, loss of deep tendon reflexes (patellar reflex) is the earliest sign of magnesium toxicity (serum level 8–10 mEq/L); respiratory depression occurs at 12–15 mEq/L; treat immediately with IV Calcium Gluconate.
- Neonates of diabetic mothers are at high risk for acute hypoglycemia within hours of birth due to persistent fetal islet cell hyperinsulinism driven by maternal hyperglycemia; monitor blood glucose closely.