Abortion is a common experience for pregnant patients: 1 in 4 people capable of pregnancy will have an abortion by age 45.1 Nearly half of all pregnancies are unintended, and about half of unintended pregnancies end in abortion.2 One in 4 patients with a uterus will need abortion care at some point.2
Most abortions occur in the first trimester of pregnancy; <2% of abortions occur at 16 weeks of gestation or later.3 There are many complex medical and social reasons why people seek abortion care in the second trimester: new diagnosis of fetal anomalies, worsening maternal comorbidities, delayed recognition of pregnancy, changes in financial or relationship status, and barriers to accessing care,4 which may increase due to changes in federal and state abortion legislation.
As most people seeking abortion care are young and healthy, most can safely receive sedation without an anesthesia provider.5 Among outpatient abortion providers, the primary reasons cited for referral to a hospital and anesthesiologist for the procedure include advanced gestational age, previous cesarean delivery, placenta previa, or patient comorbidities precluding outpatient sedation.6 Additionally, children, victims of sexual or physical abuse, or neurodiverse children and adults may particularly benefit from anesthesia services to minimize psychological trauma.7 As abortion restrictions increase across the country, those who can travel will likely present later in the pregnancy because of the barriers to accessing care. Therefore, this review focuses on the role of the anesthesiologist in providing safe anesthesia for second-trimester abortion procedures.
PHYSIOLOGIC CHANGES OF PREGNANCY
Many physiologic considerations used in obstetric anesthesia are relevant to second-trimester abortion care. Theoretically, functional residual capacity starts to decline at 20 weeks of gestational age due to the gravid uterus-restricting vertical lung expansion.8 This, paired with an increased oxygen consumption during pregnancy, may lead to a more rapid decrease in arterial oxygen tension during periods of apnea,9 although the effect is greater in the third trimester. Tracheal intubation may be more difficult secondary to oral mucosal edema, weight gain, larger breasts, and increased anteroposterior chest wall diameter impeding direct laryngoscopy. The risk of bleeding with instrumentation is increased due to engorgement of the oral and nasal mucosa.10 There is also theoretically an increase in the risk of acid reflux and aspiration due to an upward displacement and rotated axis of the stomach and a reduction in lower esophageal sphincter tone from the effect of progesterone on smooth muscle relaxation.8,11 Gastric contents should be minimal in a fasted patient for a planned abortion procedure, as long as other diagnoses are excluded. Pregnancy itself does not delay gastric emptying, although labor pain, opioids, and exogenous oxytocin can delay gastric emptying.
Additionally, the cardiac output distributed to the uterus increases significantly throughout pregnancy, with uterine artery flow increasing up to 200 mL/min by 28 weeks of gestation.12,13 This translates into an increased risk of hemorrhage with instrumentation of the uterus with procedures performed in the second trimester.
ABORTION CARE
Conventionally, dilation and curettage (D&C) is completed using suction aspiration up to 14 to 16 weeks of gestation. After 16 weeks, fetal ossification requires dilation and evacuation (D&E) with cervical preparation in the days before the procedure to decrease the risk of cervical laceration. Cervical preparation, or preprocedural dilation and softening, is initiated 24 to 48 hours before the planned procedure using a combination of medications (mifepristone, a selective progesterone receptor modulator; and misoprostol, a synthetic prostaglandin) and mechanical dilators.14
After cervical preparation is initiated, the surgical procedure should not be canceled or rescheduled, and these procedures should be prioritized as urgent and nonelective. A delay in the procedure may lead to uncontrolled preoperative fetal expulsion with resultant physical pain. While induction of labor, generally performed on a labor and delivery unit, is chosen by some patients who may desire to see or hold the fetus, inadvertent or undesired labor and fetal expulsion in a preoperative setting may cause severe psychological distress for the patient, preoperative staff, and the patient’s support person.
Cervical preparation often causes patients to present on the day of surgery with significant uterine cramping, flushing, nausea, or pyrexia related to the prostaglandin medications. The anesthesiologist may consider ordering preoperative antiemetics and analgesic medications for control of these symptoms.
Dilation and Evacuation
D&E typically begins with a paracervical injection of local anesthetic (often plain lidocaine with diluted vasopressin—important for both multimodal pain control and decreasing blood loss),15 aspirating the amniotic fluid, and then removing the fetus with forceps through the prepared cervix.16 The total procedure time varies by gestational age, parity, and provider experience but typically requires <30 minutes.
Induction Termination
The majority of second-trimester abortions in the United States are completed via D&E.16 However, in areas without providers trained in D&E or for situations in which the pregnant patient prefers to see and hold the fetus as a part of the grieving process, a medical (nonsurgical) abortion may be preferred. Medical abortion involves inducing uterine contractions with mifepristone and misoprostol, resulting in the expulsion of a previable fetus.16 This typically occurs in the labor and delivery unit.
Medical induction, similar to labor, is a painful process for the patient. Analgesia should be offered to the patient. Because this process does not result in a viable neonate, the anesthetic plan does not need to account for fetal transfer of medications. Typical limitations on intravenous (IV) narcotics or benzodiazepines in labor should be adjusted for these patients. In addition, neuraxial labor analgesia should be offered to patients undergoing induction termination if desired.
Retained placenta is a common complication of second-trimester induction terminations, and an urgent D&C to extract the placenta may be necessary in up to 10% of cases.17 Even women who are not requesting neuraxial analgesia should be considered potential surgical candidates and evaluated by the anesthesia team on admission. Volume status and accurate quantitative blood loss (QBL) should be noted by the provider before the D&C procedure; the baseline circulating volume of these patients is less than fully gravid patients, and therefore, smaller blood loss may result in significant hemodynamic instability.
COMPLICATIONS AND PROPHYLAXIS
Abortion is safer than carrying a pregnancy to term: the estimated fatality rate is 0.41 deaths per 100,0003 vs 17.4 per 100,000 in term birth,18 resulting in a 42-fold increase in risk of death for pregnancy compared to abortion. Complications with D&E are rare but increase with more advanced gestation,19 with the most common including cervical laceration (3%), hemorrhage (<1%), retained products of conception (<1%), infection (0.1%–4%), and uterine perforation (<0.5%).16 The stated risks reflect the overall population; those with cardiac conditions such as pulmonary hypertension, severe mitral or aortic stenosis, heart failure, severe coronary disease, or congenital heart disease do carry a higher risk of anesthetic complications from abortion. However, one must remember that the significant increase in cardiac output during pregnancy and physiologic stress of labor or cesarean delivery pose an even greater danger to the patient. In all settings, abortion is safer than continuing a pregnancy.
Postabortion hemorrhage, defined as bleeding >500 mL, occurs in 0.9 to 10 per 1000 cases.20 The most common cause of hemorrhage is uterine atony. Risk factors include previous cesarean delivery, gestational age >20 weeks, increasing maternal age, bleeding disorders, and history of obstetrical hemorrhage.20 Preoperative risk stratification of hemorrhage into low, moderate, or high risk based on clinical characteristics may guide decisions regarding preoperative intravascular access and resuscitation.
Common medications for uterine atony are presented in Table 1. The concentration of myometrial oxytocin receptors increases in the second trimester, with minimal expression before 20 weeks21; therefore, uterine atony associated with D&E is often best treated with methylergonovine, carboprost, or misoprostol.20 Additional strategies for managing atony refractory to medical management include placement of an intrauterine tamponade balloon, uterine artery embolization, or hysterectomy.
Table 1. -
Medications for Acute Medical Management of Postabortion Hemorrhage
| Medication |
Dosing and route |
Frequency |
Side effects |
Contraindications |
| Methylergonovine |
0.2 mg IM |
Every 2–4 h |
Hypertension |
Hypertensive disorders and cardiac disease |
| Carboprost |
0.25 mg IM |
Every 15–90 min, not to exceed 8 doses |
Diarrhea, flushing, and chills |
Active pulmonary, cardiac, renal, or hepatic disease |
| Misoprostol |
600–1000 mcg buccal, sublingual, and rectal |
Once |
Fever, nausea, and rigors |
|
| Tranexamic acid |
1000 mg IV infused over 10 min |
Every 3 h |
|
Active or history of thromboembolic disease |
| Oxytocin |
IV: 1–3 unit bolus
7.5–15 mL/h continuous infusion
IM: 10 units |
Continuous |
Hyponatremia and hypotension |
Unlikely to be effective <20 wk of gestation |
Abbreviations: IM, intramuscular; IV, intravenous.
A rare, but significant risk factor for hemorrhage even in the first trimester is placenta accreta spectrum. The risk of abnormal placentation increases with the number of previous cesarean deliveries and placental location.22 Sensitivity of preprocedure imaging is overall poor, making tertiary referral centers and the operating preferred for those with a high risk of abnormal placentation due to placenta previa and previous uterine surgeries.6
ANESTHETIC TYPES
There are multiple anesthetic options for D&E (Table 2). Staffing, cost, safety, effectiveness, side effects, and patient experience are all key factors in choice of anesthetic.23 An ideal anesthetic aims to provide anxiolysis, periprocedural comfort, and postoperative pain control, while minimizing postoperative nausea and vomiting (PONV) and cost. One must also consider the physiologic changes of the pregnant patient and be mindful of the risk of bleeding and the medications available to treat uterine atony.
Deep Sedation/Monitored Anesthesia Care
Performing the case under deep sedation ensures that the patient is comfortable enough to tolerate the procedure, avoids instrumentation of the pregnant airway, and leads to shorter operating room time, faster emergence, and shorter recovery times, all of which translate to lower costs. Deep sedation also avoids risks of oral and dental trauma or throat soreness.
Historically, anesthesiologists were taught that anatomic changes around 18 to 20 weeks of gestation from a gravid uterus, combined with decreased lower esophageal sphincter tone in pregnancy, conferred an unacceptably high aspiration risk without an advanced airway. However, a robust body of contemporary literature supports use of deep sedation without an advanced airway device for most D&E patients up through 24 weeks of gestation (Table 3). Additionally, the Serious Complication Repository (SCORE) Project found no instances of aspiration of gastric contents from data captured on 5332 general anesthetics for cesarean delivery,24 supporting that aspiration in the obstetric population is less common than previously thought.25 Evidence even supports the use of deep sedation for patients with obesity. In a retrospective cohort of 5579 pregnant people receiving abortion care in an outpatient setting with IV moderate or deep sedation (24.7% of the sample receiving propofol) without endotracheal intubation, there were no incidents of pulmonary complications or anesthesia-related adverse events in the normal weight or those with Class 1 (body mass index [BMI], 30–34.9 kg/m2) or Class 2 (BMI, 35–39.9 kg/m2) obesity.26
Table 2. -
Anesthetic Options for Dilation and Evacuation, With Pros and Cons
| Anesthetic Type |
Pro |
Con |
| Local only (paracervical block) |
Lower cost, no anesthesiologist needed |
Patient discomfort, anxiety, and/or trauma |
| Maintained airway reflexes |
Patient intolerance or failure to complete the procedure |
| Respiratory and cardiovascular functions are not affected |
| Moderate sedation |
Lower cost, no anesthesiologist needed |
Patient intolerance or failure to complete the procedure |
| Maintained airway reflexes and spontaneous ventilation |
| Neuraxial |
No airway instrumentation needed |
Longer PACU times |
| Hypotension |
| Possible loss of follow-up in the event of anesthetic complications from the procedure (eg, postdural puncture headache) |
| Deep sedation/general anesthesia with native airway |
Avoidance of airway trauma |
Suboptimal conditions for intubation if required midprocedure |
| Faster wakeup than with GA |
| Patients often amnestic |
May require assistance to maintain patent airway and spontaneous ventilation |
| General with laryngeal mask airway |
Protected airway |
Delayed awakening, increased recovery time |
| Absence of patient movement during the procedure |
Increased blood loss from atony if volatile anesthetic used |
| Patient almost always amnestic |
Airway trauma, risk of aspiration, or laryngospasm still present |
| PONV |
| General endotracheal |
Negates the need for emergency intubation |
Delayed awakening, increased recovery time |
| Increased blood loss from atony if volatile anesthetic used |
| Absence of patient movement during the procedure |
| Risk of aspiration and laryngospasm at induction and emergence |
| Patient almost always amnestic |
Airway trauma |
| PONV |
Abbreviations: GA, general anesthesia; PONV, postoperative nausea and vomiting.
Table 3. -
Review of Publications Supporting Native Airway During Dilation and Evacuation
| Author, Year |
Study design |
Gestational ages (wk) |
Incidence of anesthetic complications in deep sedation patients |
Major conclusions |
| Dean et al,48 2011 |
Retrospective cohort, n = 62,125 |
Up to 24 0/7 (18% in second trimester) |
11% required positive pressure mask ventilation, 0.2% laryngeal mask airway placed, 1 patient intubated |
No cases of aspiration |
| Gokhale et al,26 2016 |
Retrospective cohort, n = 5579 |
Up to 22 6/7 (30.6% in second trimester) |
13 patients (0.2%) required naloxone for hypoxemia or diminished respiratory effort which was associated with > median doses of anesthetic (>200 mcg fentanyl) |
No patients experienced a primary outcome of intubation, aspiration, and transfer to hospital for anesthetic-related problem. This study included obese patients. |
| Mancuso et al,49 2017 |
Retrospective cohort, n = 332 |
15–24 |
1 allergic reaction to anesthesia |
No cases of aspiration |
| 5 patients converted to general anesthesia (2 for patient discomfort and 3 for obstetric rather than anesthetic indications) |
| Aksel et al,50 2018 |
Retrospective cohort, n = 4481 (2523 of these were under deep IV sedation) |
14–19 6/7 (26%) |
2 cases of pulmonary aspiration |
0.08% incidence of aspiration |
| 20–24 (74%) |
4 cases of upper airway obstruction with desaturation to Spo
2% <90, 1 lingual nerve injury |
0.16% incidence of upper airway obstruction |
| Kim et al,51 2020 |
Retrospective cohort, n = 10,005 |
Up to 23 6/7 (10% in second trimester) |
3 D&C complications: 2 laryngospasm not requiring intubation |
No cases of aspiration and low rate of complications in the independent clinic setting |
| 3 D&E complications: 1 laryngospasm requiring intubation, 1 hypotension/bradycardia, and 1 seizure in a patient with seizure disorder |
Abbreviations: D&C, dilation and curettage; D&E, dilation and evacuation; IV, intravenous.
Deep sedation or monitored anesthesia care should routinely be considered as the default anesthetic modality for patients undergoing D&E. Authors of this narrative review favor a high-dose propofol infusion with supplemental midazolam for anxiolysis, and fentanyl and ketorolac for analgesia.
General Anesthesia
Indications for general anesthesia with an endotracheal tube may include high hemorrhage risk, underlying severe lung disease, severe obstructive sleep apnea, active vomiting, or full stomach (not nil per os [NPO]). Typical general anesthesia involves rapid-sequence induction and intubation with or without cricoid pressure.27 If a general anesthetic is chosen to minimize aspiration risk, consider preoperative aspiration prophylaxis with an H2 antagonist (famotidine) and alkalinizing agent (sodium citrate), placement of an oral gastric tube intraoperative to suction gastric contents, and extubation while the patient is awake and responding to commands.28
IV anesthetic agents, such as a propofol infusion with administration of a short-acting opioid as needed, are preferred for maintenance of general anesthesia. Providers may choose to use volatile agents at a minimum alveolar concentration (MAC) <0.5 or use exclusively IV techniques to decrease any tocolytic effect of volatile anesthetics.29 In a randomized controlled trial, patients underwent D&E at 18 to 24 weeks of gestation with IV midazolam, IV fentanyl, IV propofol, and nitrous oxide, or this same anesthetic with the addition of sevoflurane administered via facemask at a rate of 2 to 4 L/min and a concentration of 2% to 4%. The sevoflurane group was more likely to have interventions for bleeding compared to those who received IV agents alone (25% vs 16.3%) and more likely to have a measured blood loss >300 mL (15% vs 7.5%).30
Neuraxial
Neuraxial analgesia may be considered for those contraindications to sedation or general anesthesia; such contraindications may include significant cardiovascular or pulmonary disease, concerns for a very difficult airway, or patient preference. To achieve a sensory blockade from T10 to S4, a single injection with a small-gauge spinal needle of hyperbaric bupivacaine (7.5 to 10 mg) with fentanyl (10 to 20 mcg) is sufficient.28 In a randomized trial of those undergoing cervical cerclage, a spinal block with 50 mg plain 1% 2-chloroprocaine had a similar onset of sensory block at T10 but quicker recovery of motor function than with 0.5% bupivacaine.31 The use of chloroprocaine may be particularly beneficial in this population to facilitate expeditious discharge.
Neuraxial anesthesia is sufficient for blocking procedural pain and discomfort, though a short-acting benzodiazepine may be supplemented for those who request anxiolysis, sedation, and/or amnesia. Additionally, IV opioid supplementation might provide theoretical fetal analgesia; although the fetus’s capacity to feel pain is unknown, peripheral pain receptors do exist at this gestational age.32
ADDITIONAL CONSIDERATIONS
Substance Use Disorder
Substance use disorder is an independent risk factor for unintended pregnancy.33–35 Those seeking abortion care may be more likely to present with a positive urine toxicology, and this is a common reason for referral into the hospital-based setting for abortion care.6
Anesthetic risks may increase in the setting of a positive urine toxicology screen, especially in the case of methamphetamines or cocaine, although recent literature suggests that these risks may not be as high as assumed.36 While knowledge of urine toxicology results may inform the anesthetic plan, the decision is often made to proceed with the abortion rather than to wait for hopeful substance abstinence and accept the increasing procedural risk with advancing gestation. The anesthetic evaluation should include an assessment of the effects of the substance abuse, associated diseases, and end-organ injury without delay or cancelation.37
Preterm Premature Rupture of Membranes
Periviable preterm premature rupture of membrane (PPROM) occurring before fetal viability (14–24 weeks of gestation) can result in significant maternal complications, including intra-amniotic infection, endometritis, placental abruption, and retained placenta. One center found that 14% of women with periviable PROM experienced significant maternal morbidity, including sepsis, hemorrhage, infection, renal injury, and hospital readmission.38 In another contemporary observational study, patients who chose expectant management of periviable PPROM had 4.1 times the odds of developing chorioamnionitis compared to those who underwent termination (38.0% vs 13.0%) and 2.44 times the odds of postpartum hemorrhage (23.1% vs 11.0%).39 Admissions to the intensive care unit and unplanned hysterectomy only occurred after expectant management (2.8% vs 0.0% and 0.9% vs 0.0%).39
Before the Dobbs v Jackson Women’s Health Organization decision, the Texas Senate 8 bill had banned abortion when there is presence of fetal cardiac activity. A multicenter observational study of women with PPROM at <22 weeks gestational age confirmed that mandatory expectant management until spontaneous fetal demise increases risk of maternal morbidity (including chorioamnionitis and hemorrhage) compared to immediate termination in states that allow abortion (57% vs 33%).40 Additionally, septic pregnancy loss complicates 1 in 200,000 pregnancy losses but is more common in induced and illegal abortion.28 This life-threatening condition requires prompt recognition and treatment with broad-spectrum antibiotics, fluid, potentially vasoactive drugs, and surgical uterine reevacuation, and may even require hysterectomy in extreme cases.
In states with abortion restrictions that prohibit intervention until cessation of fetal cardiac activity, anesthesia care providers may perform significantly more high-risk anesthetics for patients with sepsis and hemorrhage following legally mandated expectant management of this condition. Vital sign surveillance is indicated for women undergoing prolonged expectant management to await fetal demise. Documentation of progressive tachycardia, tachypnea, fever or hypothermia, hypotension or hemodynamic instability, hypoxemia, oliguria, or maternal mental status changes would support a diagnosis of maternal sepsis. Interventions, such as IV antibiotics, vasopressor therapy, and fluid resuscitation, should not be delayed if signs of sepsis develop. Many state laws do allow for abortion to save the life of the pregnant person, but the exact point in maternal clinical deterioration at which abortion becomes legal has not been defined. Regardless, the probability of fetal survival declines with maternal deterioration and aggressive hemodynamic support.
Fetal Demise
Second-trimester fetal demise is also managed via D&E or medical induction. A unique consideration for patients experiencing a spontaneous fetal demise is the increased risk of hemorrhage and disseminated intravascular coagulation (DIC). In a large retrospective review of second-trimester D&E procedures at a hospital-based ambulatory surgical center, when fetal demise was compared to D&E for other reasons, there was a higher odds of hemorrhage (odds ratio [OR], 2.9) and DIC (OR, 12.3).41 While the absolute rate of DIC is low, the care team may consider ordering a coagulation panel and complete blood count preoperatively for those with fetal demise, especially if planning neuraxial analgesia.
Presence of a concomitant placental abruption and organ dysfunction, which may present as anuria, is a particularly concerning constellation of findings.
Cost
Abortion cost can be a significant burden and a barrier to care with federal and private insurance limiting coverage. The Hyde Amendment prevents federal funding from being used for abortion care, forcing many low-income people or those used by the federal government (eg, the military or the Peace Corps) to pay for abortion out of pocket—at the cost of 2 times the median monthly income.42 Anesthesia care may cost more than the actual abortion procedure, so anesthesiologists should be thoughtful in their anesthetic approaches to minimize financial burden while providing safe and standard care. This may be an additional rationale for providing deep sedation rather than general anesthesia when clinically reasonable. This minimizes charges for expensive anesthetic agents, such as succinylcholine, sugammadex, neostigmine, and glycopyrrolate. Optimizing for shorter intraoperative and recovery room times may also translate to significant cost savings for patients.
Pain Control
Multimodal analgesia should be used to decrease opioid requirements. Acetaminophen (1000 mg), preferably administered orally before the procedure for its lower cost, and ketorolac (at a dose of 15 or 30 mg) are effective at treating pain after gynecologic surgery.43 Small amounts of short-acting IV opioids, such as fentanyl, may be indicated for the procedure itself, but over-the-counter acetaminophen and ibuprofen are sufficient for postdischarge analgesic management, and these patients do not routinely receive a narcotic prescription postoperatively.
Postoperative Nausea and Vomiting
Female sex, gynecologic surgery, and preoperative prostaglandin administration place patients undergoing a D&E procedure at high risk of PONV.44 Controlling nausea and vomiting is important for improving patient comfort and decreasing length of time in the postanesthesia care unit (PACU). Strategies for decreasing PONV include total intravenous anesthesia (TIVA) with propofol, minimizing narcotics, and prophylactic administration of at least 2 pharmacologic antiemetics of different drug classes, including 5-hydroxytryptamine (5-HT3) receptor antagonists (ondansetron), corticosteroids (dexamethasone), dopamine antagonists (haloperidol), phenothiazines (promethazine and prochlorperazine), or anticholinergics (transdermal scopolamine).45
Severe Maternal Cardiopulmonary Disease
Anesthetic management of pregnancy termination in patients with severe cardiopulmonary disease, such as pulmonary arterial hypertension, cystic fibrosis, or severe congenital or acquired cardiac disease, is beyond the scope of this review, but it is discussed in detail in Chestnut’s Obstetric Anesthesia.46,47 In general, anesthetic management of such patients may necessitate multidisciplinary plans formulated with cardiology and cardiac anesthesia specialists to safely tailor an anesthetic plan for the patient.
DISCUSSION
While anesthesia providers currently care for the minority of those seeking abortion care, the anticipated increase in restrictions to abortion access suggests that more pregnant people may present in the second trimester for care. In addition, anesthesiologists in abortion-restricted states and facilities may need to care for patients with fetal demise in the second trimester. Anesthesia care providers should note that deep sedation without placement of an advanced airway device is an evidence-based and reasonable first-choice anesthetic modality, with safety demonstrated in several large studies through 24 weeks of gestational age.
Anesthesiologists can play an important role in documenting maternal deterioration or risk of deterioration in cases of current or impending hemodynamic instability to categorize a patient condition as life-threatening and requiring uterine evacuation. It is likely that more of these cases will be completed in the operating room, and anesthesia providers should be prepared to provide safe, compassionate anesthetic management.
DISCLOSURES
Name: Elizabeth Ozery, MD.
Contribution: This author wrote and handled the manuscript.
Name: Jessica Ansari, MD.
Contribution: This author helped develop a content outline, solicited the review article, and edited the manuscript.
Name: Simranvir Kaur, MD.
Contribution: This author edited the manuscript.
Name: Kate A. Shaw, MD, MS.
Contribution: This author edited the manuscript.
Name: Andrea Henkel, MD, MS.
Contribution: This author helped develop a content outline and wrote the manuscript.
This manuscript was handled by: Jill M. Mhyre, MD.
REFERENCES
1. Jones RK, Jerman J. Population group abortion rates and lifetime incidence of abortion: United States, 2008–2014. Am J Public Health. 2017;107:1904–1909.
2. Finer LB, Zolna MR. Declines in unintended pregnancy in the United States, 2008–2011. N Engl J Med. 2016;374:843–852.
3. Kortsmit K, Mandel MG, Reeves JA, et al. Abortion surveillance—United States, 2019. MMWR Surveill Summ. 2021;70:1–29.
4. Jones RK, Finer LB. Who has second-trimester abortions in the United States? Contraception. 2012;85:544–551.
5. Turok DK, Gurtcheff SE, Esplin MS, et al. Second trimester termination of pregnancy: a review by site and procedure type. Contraception. 2008;77:155–161.
6. O’Connell K, Jones HE, Lichtenberg ES, Paul M. Second-trimester surgical abortion practices: a survey of National Abortion Federation members. Contraception. 2008;78:492–499.
7. Prager SW, Oyer DJ. Second-trimester surgical abortion. Clin Obstet Gynecol. 2009;52:179–187.
8. Kacmar RM, Gaiser R. Chapter 2: physiologic changes of pregnancy. Chestnut DH, Wong CA, Tsen LC, , eds. In: Chestnut’s Obstetric Anesthesia: Principles and Practice. 6th ed. Elsevier; 2020:13–37
9. Archer GW Jr, Marx GF. Arterial oxygen tension during apnoea in parturient women. Br J Anaesth. 1974;46:358–360.
10. Leontic EA. Respiratory disease in pregnancy. Med Clin North Am. 1977;61:111–128.
11. Van Thiel DH, Gavaler JS, Stremple J. Lower esophageal sphincter pressure in women using sequential oral contraceptives. Gastroenterology. 1976;71:232–234.
12. Palmer SK, Zamudio S, Coffin C, Parker S, Stamm E, Moore LG. Quantitative estimation of human uterine artery blood flow and pelvic blood flow redistribution in pregnancy. Obstet Gynecol. 1992;80:1000–1006.
13. Thaler I, Manor D, Itskovitz J, et al. Changes in uterine blood flow during human pregnancy. Am J Obstet Gynecol. 1990;162:121–125.
14. Diedrich JT, Drey EA, Newmann SJ. Society of family planning clinical recommendations: cervical preparation for dilation and evacuation at 20-24 weeks’ gestation. Contraception. 2020;101:286–292.
15. Schulz KF, Grimes DA, Christensen DD. Vasopressin reduces blood loss from second-trimester dilatation and evacuation abortion. Lancet. 1985;2:353–356.
16. Steinauer J, Jackson A, Grossman D. ACOG Practice Bulletin No.135: second-trimester abortion. Obstet Gynecol. 2013;121:1394–1406.
17. Sonalkar S, Ogden SN, Tran LK, Chen AY. Comparison of complications associated with induction by misoprostol versus dilation and evacuation for second-trimester abortion. Int J Gynaecol Obstet. 2017;138:272–275.
18. Joseph KS, Boutin A, Lisonkova S, et al. Maternal mortality in the United States: recent trends, current status, and future considerations. Obstet Gynecol. 2021;137:763–771.
19. Grossman D, Blanchard K, Blumenthal P. Complications after second trimester surgical and medical abortion. Reprod Health Matters. 2008;16(suppl 31):173–182.
20. Kerns J, Steinauer J. Management of postabortion hemorrhage: release date November 2012 SFP Guideline #20131. Contraception. 2013;87:331–342.
21. Whitehouse K, Tschann M, Soon R, et al. Effects of prophylactic oxytocin on bleeding outcomes in women undergoing dilation and evacuation: a randomized controlled trial. Obstet Gynecol. 2019;133:484–491.
22. Silver RM, Landon MB, Rouse DJ, et al.; National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Maternal morbidity associated with multiple repeat cesarean deliveries. Obstet Gynecol. 2006;107:1226–1232.
23. Calvache JA, Delgado-Noguera MF, Lesaffre E, Stolker RJ. Anaesthesia for evacuation of incomplete miscarriage. Cochrane Database Syst Rev. 2012;4:CD008681.
24. D’Angelo R, Smiley RM, Riley ET, Segal S. Serious complications related to obstetric anesthesia: the serious complication repository project of the Society for Obstetric Anesthesia and Perinatology. Anesthesiology. 2014;120:1505–1512.
25. Warner MA, Warner ME, Weber JG. Clinical significance of pulmonary aspiration during the perioperative period. Anesthesiology. 1993;78:56–62.
26. Gokhale P, Lappen JR, Waters JH, Perriera LK. Intravenous sedation without intubation and the risk of anesthesia complications for obese and non-obese women undergoing surgical abortion: a retrospective cohort study. Anesth Analg. 2016;122:1957–1962.
27. Russell R. Chapter 29: the difficult airway: risk, assessment, prophylaxis, and management. In: Chestnut DH, Wong CA, Tsen LC, , eds. Chestnut’s Obstetric Anesthesia: Principles and Practice. 6th ed. Elsevier; 2020:692–723
28. Arendt KW, Long ME. Chapter 16: problems of early pregnancy. In: Chestnut DH, Wong CA, Tsen LC, , eds. Chestnut’s Obstetric Anesthesia: Principles and Practice. 6th ed. Elsevier; 2020: 350–367
29. Setty T, Fernando R. Chapter 22: systemic analgesia: parenteral and inhalational agents. In: Chestnut DH, Wong CA, Tsen LC, , eds. Chestnut’s Obstetric Anesthesia: Principles and Practice. 6th ed. Elsevier; 2020: 453–473
30. Micks E, Edelman A, Botha R, Bednarek P, Nichols M, Jensen JT. The effect of sevoflurane on interventions for blood loss during dilation and evacuation procedures at 18-24 weeks of gestation: a randomized controlled trial. Contraception. 2015;91:488–494.
31. Camponovo C, Wulf H, Ghisi D, et al. Intrathecal 1% 2-chloroprocaine vs. 0.5% bupivacaine in ambulatory surgery: a prospective, observer-blinded, randomised, controlled trial. Acta Anaesthesiol Scand. 2014;58:560–566.
32. Rollins MD. Chapter 7: anesthesia for fetal surgery and other intrauterine procedures. In: Chestnut DH, Wong CA, Tsen LC, , eds. Chestnut’s Obstetric Anesthesia: Principles and Practice. 6th ed. Elsevier; 2020:132–154
33. Hittner JB. Meta-analysis of the association between methamphetamine use and high-risk sexual behavior among heterosexuals. Psychol Addict Behav. 2016;30:147–157.
34. Black KI, Stephens C, Haber PS, Lintzeris N. Unplanned pregnancy and contraceptive use in women attending drug treatment services. Aust N Z J Obstet Gynaecol. 2012;52:146–150.
35. Reardon DC, Coleman PK, Cougle JR. Substance use associated with unintended pregnancy outcomes in the National Longitudinal Survey of Youth. Am J Drug Alcohol Abuse. 2004;30:369–383.
36. Githens T, DeBaun MR, Campbell ST, et al. Rates of perioperative complications among patients undergoing orthopedic trauma surgery despite having positive results for methamphetamine. Orthopedics. 2019;42:192–196.
37. Pulley DD. Preoperative evaluation of the patient with substance use disorder and perioperative considerations. Anesthesiol Clin. 2016;34:201–211.
38. Dotters-Katz SK, Panzer A, Grace MR, et al. Maternal morbidity after previable prelabor rupture of membranes. Obstet Gynecol. 2017;129:101–106.
39. Sklar A, Sheeder J, Davis AR, Wilson C, Teal SB. Maternal morbidity after preterm premature rupture of membranes at <24 weeks’ gestation. Am J Obstet Gynecol. 2022;226:558.e1–558.e11.
40. Nambiar A, Patel S, Santiago-Munoz P, Spong CY, Nelson DB. Maternal morbidity and fetal outcomes among pregnant women at 22 weeks’ gestation or less with complications in 2 Texas hospitals after legislation on abortion. Am J Obstet Gynecol. 2022;227:648–650.e1.
41. Kerns JL, Ti A, Aksel S, Lederle L, Sokoloff A, Steinauer J. Disseminated intravascular coagulation and hemorrhage after dilation and evacuation abortion for fetal death. Obstet Gynecol. 2019;134:708–713.
42. Zuniga C, Thompson TA, Blanchard K. Abortion as a catastrophic health expenditure in the United States. Womens Health Issues. 2020;30:416–425.
43. Khadge SD, Tanella A, Lin HM, Ren I, Michaels I, Hyman JB. Retrospective study of the analgesic effect of a 15 mg dose of ketorolac in ambulatory gynecologic surgery. J Clin Anesth. 2020;66:109904.
44. Apfel CC, Heidrich FM, Jukar-Rao S, et al. Evidence-based analysis of risk factors for postoperative nausea and vomiting. Br J Anaesth. 2012;109:742–753.
45. Nathan N. Management of postoperative nausea and vomiting: the 4th consensus guidelines. Anesth Analg. 2020;131:410.
46. Vidovich MI. Chapter 41: cardiovascular disease. In: Chestnut DH, Wong CA, Tsen LC, , eds. Chestnut’s Obstetric Anesthesia: Principles and Practice. 6th ed. Elsevier; 2020:987–1032
47. Lindeman KS. Chapter 52: respiratory disease. In: Chestnut DH, Wong CA, Tsen LC, , eds. Chestnut’s Obstetric Anesthesia: Principles and Practice. 6th ed. Elsevier; 2020:1231–1247
48. Dean G, Jacobs AR, Goldstein RC, Gevirtz CM, Paul ME. The safety of deep sedation without intubation for abortion in the outpatient setting. J Clin Anesth. 2011;23:437–442.
49. Mancuso AC, Lee K, Zhang R, Hoover EA, Stockdale C, Hardy-Fairbanks AJ. Deep sedation without intubation during second trimester surgical termination in an inpatient hospital setting. Contraception. 2017;95:288–291.
50. Aksel S, Lang L, Steinauer JE, et al. Safety of deep sedation without intubation for second-trimester dilation and evacuation. Obstet Gynecol. 2018;132:171–178.
51. Kim R, Pelletier A, Donnenfeld B, Delli-Bovi L, Bartz D. Safety of deep sedation without intubation during surgical abortion in the independent clinic setting. Contraception. 2020;101:298–301.
