Retained placenta and uterine relaxation
Stem
A 28-year-old G2P2, 66 kg, had a spontaneous vaginal delivery 45 minutes ago without an epidural. Third stage was managed actively with oxytocin, but the placenta has not delivered. Weighed blood loss is 650 mL and she is trickling. Blood pressure is 110/68, heart rate 104. She ate toast two hours before delivery. Hemoglobin was 11.2 g/dL on admission and platelets are normal. The obstetrician wants to remove it manually in the operating room.
Question
How will you manage her anesthetic?
Ideal answer
HeadlineShe is bleeding but stable, so I give a spinal and have nitroglycerin drawn up; instability or heavy bleeding turns this into a rapid sequence general anesthetic.
- Prepare first: two large-bore lines, crossmatch, weighed loss, because retained placenta raises hemorrhage risk about fivefold.1,2
- Sodium citrate 30 mL, famotidine, metoclopramide, then spinal, to about T10, because she ate two hours ago and avoiding her airway is safer.3
- Nitroglycerin 50–100 mcg IV for a clamped-down uterus, because it relaxes within about a minute and wears off fast.4,5
- Destabilizes: rapid sequence general, ketamine or etomidate, volatile only until the placenta is out.3
- Cefazolin 2 g, then oxytocin: a first-generation cephalosporin is recommended,6 3 g at 120 kg or more,7 and oxytocin 40 units over 4 hours if she bled.2
Watch for: no cleavage plane, which means accreta, and hypotension after nitroglycerin.2
Breaking down the answer
- Definition sets the clock — retained means undelivered 30 minutes after active or 60 minutes after physiological management; it affects 2–3% of deliveries.2 Changes if: second-trimester loss, where up to 180 minutes of watchful waiting is acceptable without bleeding.2
- Regional or general — ASA names no preferred technique;3 a spinal avoids the pregnant airway and aspiration, but a sympathectomy in a hypovolemic woman can collapse her. Changes if: ongoing heavy bleeding, shock or coagulopathy; then general anesthesia with induction doses reduced.
- Nitroglycerin — releases nitric oxide to relax smooth muscle; IV boluses act in 75–95 seconds,4 and 100–200 mcg relaxed the uterus within 45–60 seconds for no more than 2 minutes.5 Changes if: she is hypotensive; I restore pressure first.
- Nitroglycerin and oxygen — it can cause severe hypoxemia even as a bolus, likely by blunting hypoxic pulmonary vasoconstriction.4 Changes if: lung disease, shunt, cardiac disease or severe anemia; I reduce the dose and watch SpO2.4
- Oxytocin timing — a routine infusion before removal makes the procedure harder; it is for active bleeding.2 Umbilical vein uterotonic injection is no longer recommended.2 Changes if: she bleeds heavily while waiting.
- Antibiotics — WHO recommends routine prophylaxis: ampicillin or a first-generation cephalosporin, or amoxicillin-clavulanate;6 UK units use co-amoxiclav 1.2 g or clindamycin with gentamicin.2 Changes if: chorioamnionitis is already being treated.
Follow-up question
Under the spinal, the obstetrician cannot find a plane between placenta and uterus and is pulling piecemeal. Blood loss is now 1,900 mL, pressure 80/40, heart rate 136, and she says she feels faint. What do you do?
Follow-up answer
HeadlineThis is placenta accreta with hemorrhagic shock; I tell the obstetrician to stop pulling and call the consultant, and I call for help.
I activate massive transfusion and give blood by rapid infuser. Tranexamic acid 1 g IV at 1 mL/min, since she is within 3 hours of birth.8 I convert to general anesthesia by rapid sequence with ketamine at a reduced dose, place an arterial line, and send fibrinogen and viscoelastic tests. The team prepares for interventional radiology or hysterectomy.2 I reassess pressure, gases and coagulation every 15–30 minutes.
Pitfalls that cost points
- A spinal in a woman who is already tachycardic and hypotensive.
- Nitroglycerin given into hypotension, or with no vasopressor drawn up.
- Leaving a deep volatile running after removal, adding atony to her bleeding.
Rapid-fire
Q: What sublingual dose of nitroglycerin is used? A: About 1 mg; IV boluses are 50–100 mcg.4
Q: What else relaxes the uterus? A: High-concentration volatile under general anesthesia, and beta-agonists, which cause tachycardia and hypotension.5
Q: When does tranexamic acid stop helping? A: Starting it more than 3 hours after birth confers no benefit; repeat 1 g if bleeding continues at 30 minutes.8
Q: What does excessive force on an accreta cause? A: Life-threatening hemorrhage, often ending in hysterectomy.1
Numbers to know
| Item | Value |
|---|---|
| Retained placenta | >30 min active, >60 min physiological; 2–3% of births2 |
| Hemorrhage risk | About fivefold1 |
| Nitroglycerin IV | 50–100 mcg boluses; onset 75–95 s4 |
| Nitroglycerin duration | ≤2 min after 100–200 mcg5 |
| Oxytocin after removal | 40 units in 500 mL over 4 h if bleeding2 |
| Tranexamic acid | 1 g IV at 1 mL/min within 3 h8 |
Links
- Obstetric hemorrhage: previa, accreta, atony, Uterotonics and tocolytics, Spinal anesthesia: dosing, spread, hypotension, Rapid sequence induction and full stomach, aspiration, Massive hemorrhage and transfusion
- FIGO/ICM joint statement on tranexamic acid for postpartum hemorrhage (2021); ACOG Practice Bulletin 183 (Postpartum Hemorrhage)
Sources
- 1.Retained placenta · Patient.info (professional reference), 2015 · patient.infoFivefold PPH risk (99% CI 3.36-7.87); no RCTs of antibiotic prophylaxis. Last updated 2015.
- 2.Retained Placenta Management (552), version 2 · NHS Greater Glasgow and Clyde, 2022 · rightdecisions.scot.nhs.ukReviewed 2022, next review 2027.
- 3.Practice Guidelines for Obstetric Anesthesia (2016), summary · ASA Task Force on Obstetric Anesthesia and SOAP (summarized by Speciality Medical Dialogues), 2016 · speciality.medicaldialogues.inNo preferred technique for retained placenta; general with a tube in major hemorrhage; nitroglycerin as an alternative to terbutaline or volatile; aspiration prophylaxis before surgical procedures.
- 4.Obstetric use of nitroglycerin: Anesthetic implications · Saudi Journal of Anaesthesia (Saroa et al.), 2013 · pmc.ncbi.nlm.nih.gov
- 5.The successful use of nitroglycerin for uterine hyperstimulation (case report, citing Axemo et al.) · Medicina (Kaunas) (Takakura et al.), 2021 · pmc.ncbi.nlm.nih.govCites Axemo: 100-200 mcg IV relaxed the uterus within 45-60 s, lasting no more than 2 min, in 22 manual removals.
- 6.Consolidated guidelines for the prevention, diagnosis and treatment of postpartum haemorrhage: antibiotics for manual removal of placenta · WHO (via BIGG recommendations database), 2025 · bigg-rec.bvsalud.org
- 7.Clinical practice guidelines for antimicrobial prophylaxis in surgery · ASHP / IDSA / SIS / SHEA (Bratzler et al., Am J Health-Syst Pharm), 2013 · ashp.orgTable 2: cefazolin 2 g adult dose, 3 g for patients weighing 120 kg or more; pediatric 30 mg/kg.
- 8.Joint statement of recommendation for the use of tranexamic acid for the treatment of postpartum haemorrhage · FIGO / ICM, 2021 · figo.org
Facts on this page were checked against these sources on Oct 22, 2026. Guidelines change; confirm doses against current institutional protocols.