A Retrospective Examination of Acupuncture and Acupressure for Patients with Severe Preeclampsia

Abstract

Background:

Preeclampsia is a leading cause of maternal mortality, puerperal ICU admission, and iatrogenic preterm delivery. Some small studies suggest that acupuncture and acupressure may improve blood pressure, but few studies have examined the impact of these treatments on outcomes in patients with preterm preeclampsia with severe features.

Objective:

This retrospective chart review study assessed if acupuncture/acupressure (AQ/AP) in conjunction with routine care is associated with longer time from admission to delivery or gestational age at delivery in hospitalized patients with preterm preeclampsia compared to routine care alone. Secondary outcomes included breakthrough antihypertensive use, mean arterial pressure (MAP), postpartum length of stay, ICU admission, measures of hepatic and renal function, platelet counts, birthweights, and 5-min Apgar scores.

Study Design:

This was a retrospective matched cohort study (2010–2020) of patients with preterm preeclampsia with severe features admitted for expectant management. Patients receiving AQ/AP were matched with controls who received only routine care.

Results:

The final sample of 100 matched pairs found the mean latency period from admission to delivery was 2.5 days longer in the AQ/AP group (95% CI: 0.81–4.26, p = 0.004). Breakthrough antihypertensive medication use, changes in MAP, and other biomarkers did not differ significantly.

Conclusion:

Among patients hospitalized for preeclampsia with severe features, those who received acupuncture and/or acupressure treatment had a longer time to delivery than matched controls, but AQ/AP treatment was not significantly associated with MAP or use of breakthrough antihypertensive medication.

INTRODUCTION

New-onset hypertensive disorders of pregnancy doubled in the United States between 2007 and 2019.¹ Preeclampsia is a leading cause of maternal mortality, puerperal ICU admission, and iatrogenic preterm delivery in the United States.^2–6 American College of Obstetricians and Gynecologists (ACOG) clinical management guidelines for hypertensive disorders of pregnancy vary by gestational age (GA) and severity of symptoms. Some patients with early preterm preeclampsia with severe features may be candidates for expectant management, with the goal of pregnancy prolongation to 34 weeks to improve neonatal outcomes.^7,8 Delivery is recommended for worsening disease, which can include poorly controlled hypertension despite up-titration of antihypertensive medication, non-reassuring fetal status, or signs of end-organ dysfunction.⁷

Acupuncture and acupressure treatments may improve blood pressure (BP), whether administered alone^9,10 or with antihypertensive medications.^10–15 Other research has found acupuncture and acupressure may improve liver and kidney function.^16–22 One non-randomized pilot study of patients with preeclampsia found no difference in BP immediately after a 2-week/10-treatment period but found lower BP at delivery and postpartum among the acupuncture group compared to standard care alone.²³

This study examined the addition of acupuncture/acupressure (AQ/AP) to standard care in patients hospitalized with preterm preeclampsia with severe features. The study compared outcomes for pregnant patients who received adjunctive AQ/AP to usual care to a matched control group. The hypothesis was that AQ/AP treatment is associated with prolonged latency to delivery, improved BP control, decreased need for antihypertensives, and improved measures of hepatic and renal function.

METHODS

This retrospective, observational study used electronic health record (EHR) data of pregnant patients hospitalized with preeclampsia with severe features at two metropolitan hospitals within a single health system. This study was determined exempt by the system-wide Institutional Review Board.

The study sample included patients who gave birth between January 2010 and October 2020 at one hospital and between January 2015 and October 2020 for the second hospital, reflecting when AQ/AP were available. Patients were included if their GA at the time of admission was 23w0d-33w6d, received a diagnosis of preeclampsia with severe features (as defined by the ACOG Hypertension in Pregnancy Task Force),²⁴ and had a documented plan for expectant management. Patients were excluded if they delivered within 24 h of admission, had preeclampsia or gestational hypertension without severe features, or did not consent to the use of their EHR data for research.

The treatment group included patients who received at least one AQ/AP session, and the control group included patients who did not have acupuncture or acupressure. Patients in both the AQ/AP and control groups received standard care. Patients selecting AQ/AP could choose acupuncture, acupressure, or both. A typical integrative medicine consult starts with education and explanation of services, patient assessment, and a shared decision upon the approach to care. For patients new to these therapies, treatment often starts with acupressure (Table 1). For patients who received acupuncture treatments, the number of needles, depth, duration, and manual stimulation were at the discretion of the licensed acupuncturist, and only manual stimulation was used. Verbal consent was given for acupressure, while patients who chose acupuncture signed a consent form in compliance with state medical board requirements. The consent process reviewed risks of pain, infection, bruising, and feeling faint or lightheaded. Patients getting acupuncture received a Traditional East Asian Medicine pattern diagnosis which guides treatment (typically 12–20 points for 20–30 min). Treatment points were generally located on the arms/hands, lower legs/feet, head, and ears. For patients receiving acupressure, 4–6 points along the neck, shoulders, lower limbs, hands, and feet are given manual pressure for a duration of 20–30 min. Treatments were repeated three times weekly depending on clinical circumstances.

Table 1.

Typical Acupuncture and Acupressure Points Used for Preeclampsia Patients

Point	Pinyin^a	Therapeutic function^b
Acupuncture points
KI 7	Fuliu	Benefits Kidney; regulates water passage to treat edema
KI 9	Zhubin	Clears heat and regulates Qi; Happy Baby points
LR 3	Taichong	Subdues Liver Yang; clears the head and eyes; Spreads Liver Qi; nourishes Liver Blood and yin
PC 6	Neiguan	Clears heat; unbinds chest and regulates Qi; regulates Heart and calms spirit
GB 20	Fengchi	Benefits head and eyes; eliminates wind
ST 36	Zusanli	Tonifies Qi and nourishes Blood and yin
TE 5	WaiGuan	Expels wind and benefits the head and ears; clears heat
GB 41	Zulingqi	Spread Liver Qi; clears head and benefits eyes; benefits chest and costal region
Ear Apex	N/A	Clear heat; lower BP
Ear Shen Men	N/A	Lower BP; calm Shen
Ear Liver	N/A	Regulates Liver, Qi and nourishes Blood
Ear Kidney	N/A	Regulates and replenishes Kidney
Ear Lower BP	N/A	Lowers BP
Acupressure points
KI 1	Yangguan	Descends excess from head and calms Shen
LR 3	Taichong	Subdues Liver Yang; Clears the head and eyes; Spreads Liver Qi; nourishes Liver Blood & yin
PC 6	Neiguan	Clears heat; unbinds chest and regulates Qi; regulates Heart and calms spirit
GB 20	Fengchi	Benefits head and eyes; eliminates wind

Chinese name for the point.

Therapeutic functions from Deadman, Al-Khafaji, Baker.²⁵

N/A, not applicable; BP, blood pressure.

The primary outcomes were time from admission to delivery and GA at delivery. Secondary outcomes included breakthrough antihypertensive use, maternal ICU admission, postpartum length of stay (LOS), and differences in mean arterial pressure (MAP), aspartate aminotransferase (AST), creatinine, and platelet count. Breakthrough medications included IV hydralazine, IV labetalol, and immediate-release nifedipine, with documentation of all doses given between admission and delivery. Neonatal measures included birthweight and Apgar scores at 5 min.

Baseline data included maternal age, race/ethnicity, insurance status, year of admission, GA on admission, parity, presence of multiple gestations, and preexisting chronic hypertension. Race and ethnicity are collected via self-report in the registration process. For analysis, race and ethnicity were combined: Asian-Not Hispanic/Latino (NHL), Black-NHL, Hispanic/Latino, White-NHL, and none of the above.

Intervention-related measures collected for the treatment group included intervention type (acupuncture, acupressure, or both) and the number of sessions that took place before delivery. Year of admission was used to create an admission period measure to align with changes in integrative medicine treatment and preeclampsia treatment guidelines to be used during matching. The admission period indicated whether care occurred before the release of the ACOG Hypertension in Pregnancy Task Force guidelines that changed diagnostic criteria and management recommendations of preeclampsia in 2013, between 2013 and 2019, or after 2019.²⁴ In 2019, the integrative medicine consult order was standardized at our institutions and added to the routine antepartum order set, resulting in increased referrals and potentially changing the patient population receiving AQ/AP.

A risk-set matched pairs design was used based on multiple criteria. For a control to be an eligible match, their pregnancy had to continue at least 12 h after the time of the first AQ/AP session of the proposed treated patient, which we refer to as the “matching time.” This ensured that the control was still “at risk” of receiving acupuncture or acupressure at the matching time (Fig. 1). Matching was done on the propensity score, which was modeled using Cox proportional hazards regression with an outcome of the time to AQ/AP treatment with control patients censored 12 h prior to their delivery time.²⁶ The model included patient’s age, parity (nulliparous/multiparous), race and ethnicity, pregnancy type (singleton/multiple gestation), preexisting chronic hypertension, admission period, and use of breakthrough antihypertensive medications within the first 24 h of admission. Possible control matches for an AQ/AP patient were within a caliper of 0.45 standard deviations with respect to the propensity score, and the final chosen match was the one with the closest value to the propensity score of the treated patient (i.e., one-to-one nearest neighbor matching). Finally, treated and control patients had a GA at admission within 5 days of each other. A treated patient was unmatched and excluded from the analysis if no control patients met all criteria.

FIG. 1.

Matching process. Std, standard; ACU, acupuncture.

Descriptive statistics and standardized mean differences (SMDs) were used to examine baseline characteristics and confirm comparability of the matched samples. The imbalance for variables with SMDs below 0.1 was considered minimal, while those below 0.2 showed a small imbalance, and variables with SMDs above 0.2 show unacceptable medium to high imbalance. The caliper for the matching process was chosen to prevent any SMDs above 0.2, which was unacceptable, and to keep differences below 0.1 for most variables (i.e., we aimed for minimal imbalance). There were three variables (insurance status, number of times breakthrough medications were administered within 24 h of admit, and the MAP at admission) that were not included in the Cox model used for matching but had their SMD’s considered to choose the caliper for the model and ensure balance was attained for these variables in addition to those included in the model. Primary and secondary outcomes were compared using matched pairs t-tests and confidence intervals for continuous measures and McNemar tests for categorical variables. For the primary outcomes, we also conducted a signed rank test.

Use of breakthrough antihypertensive use was defined three ways: (1) number of times medication was administered within 12 h of matching, (2) number of times medication was administered between match time and delivery, and (3) the number of times per day that breakthrough medications were administered between match time and delivery. Differences in MAP were based on the maximum MAP for 4- and 12-h windows before and after matching time. Differences in AST and creatinine were calculated from maximum values from admission to matching and from matching to delivery; differences in platelet counts were calculated from minimum values during the same times.

The sample size of the matched cohort included all eligible patients who received AQ/AP and were successfully matched. This process led to 100 pairs in the matched cohort that has 83% and 78% power to detect a small-to-medium standardized effect size (Cohen’s d) of 0.35 under the assumptions of the matched pairs t-test at the 5% significance level and correlations between matched pairs of 0.3 and 0.2, respectively. These correlations respectively correspond to an effective standardized effect size of 0.296 and 0.277 on the difference of the matched pairs’ outcomes. All analyses were carried out in R version 4.1.2.²⁷

RESULTS

There were 498 patients that met inclusion criteria. Of these, 143 received AQ/AP and 355 did not. These patients differed on some baseline factors (Table 2), with some variables having standardized mean differences as high as 0.59 (Supplementary Appendix S1). The pre-match median time from admission to first AQ/AP session for the 143 patients receiving AQ/AP was 3.7 days. Meanwhile, the 355 control patients were delivering at a median of 3.2 days after admission, showing that several control patients delivered before or at about the same time as AQ/AP patients were first treated and were no longer at risk, a situation known as immortal time bias. This potential bias was addressed with the matching procedure, where controls needed to remain pregnant (“at risk”) for at least 12 h after the matched treated patient had their first AQ/AP session.

Table 2.

Comparison of Acupuncture/Acupressure Patients and Control Patients Pre- and Post-Matching

	Original		Matched
	Control	Acupuncture/ acupressure	Control	Acupuncture/ acupressure
	n = 355	n = 143	n = 100	n = 100
Gestational age in weeks	30.6 ± 2.56	30.2 ± 2.69	30.8 ± 2.52	30.8 ± 2.52
Maternal age in years	30.8 ± 6.35	31.8 ± 5.76	31.5 ± 7.56	31.8 ± 6.05
Multiparous	153 (43.1)	64 (44.8)	47 (47.0)	43 (43.0)
Multiple gestation	46 (13.0)	15 (10.5)	15 (15.0)	12 (12.0)
Preexisting hypertension	13 (3.7)	10 (7.0)	9 (9.0)	7 (7.0)
Admitted before 2013	98 (27.6)	9 (6.3)	5 (5.0)	5 (5.0)
Admitted after 2019	26 (7.3)	22 (15.4)	14 (14.0)	14 (14.0)
Admission first MAP	114.3 ± 14.66	115.6 ± 13.98	115.9 ± 14.98	116.2 ± 14.16
Received breakthrough medication within 24 h of admit	103 (29.0)	51 (35.7)	40 (40.0)	36 (36.0)
Number of times breakthrough medications were administered within 24 h of admit	0.7 ± 1.35	0.8 ± 1.52	0.9 ± 1.48	0.9 ± 1.67
Race and Ethnicity
Hispanic/Latino	22 (6.2)	8 (5.6)	6 (6.0)	5 (5.0)
NHL Asian	25 (7.0)	9 (6.3)	8 (8.0)	6 (6.0)
NHL Black or African American	80 (22.5)	21 (14.7)	19 (19.0)	15 (15.0)
NHL White	204 (57.5)	97 (67.8)	61 (61.0)	67 (67.0)
None of the above	24 (6.8)	8 (5.6)	6 (6.0)	7 (7.0)
Insurance
Contracted Commercial	234 (65.9)	102 (71.3)	67 (67.0)	67 (67.0)
Medicaid	121 (34.1)	41 (28.7)	33 (33.0)	33 (33.0)
Median days to AQ/AP for those treated and to delivery for controls (Pre-match)	3.2	3.7	NA	NA
Median days to match time (first AQ/AP session)	NA	NA	2.7	2.7

Data are mean ± standard deviation or n (%).

MAP, mean arterial pressure; NHL, not Hispanic/Latino; AQ/AP, acupuncture/acupressure; NA, not applicable.

The final sample consisted of 100 AQ/AP patients and 100 controls matched at a median time of 2.7 days after admission who had comparable baseline characteristics with standardized mean differences of <0.10 for all baseline factors except for two race/ethnicity categories (Supplementary Appendix A1). After matching, mean GA on admission was 30.8 ± 2.52 weeks for both groups (Table 2). Preexisting hypertension was present for 7% of AQ/AP patients and 9.0% of matched control patients. Average MAP on admission was similar between groups. Breakthrough antihypertensives in the first 24 hours were administered for 36.0% of AQ/AP patients and 40.0% of controls. The number of AQ/AP treatments between admission and delivery ranged from 1 to 12, with a median of 2 (Table 3). Among the 100 matched patients with AQ/AP, 46% received acupressure only, 7% received acupuncture only, and 47% received both acupuncture and acupressure.

Table 3.

Acupuncture and Acupressure Treatment Details by Sample

	Original sample	Unmatched	Matched
	n = 143	n = 43	n = 100
Treatment type
Acupuncture only	11 (7.7)	4 (9.3)	7 (7.0)
Acupressure only	66 (46.2)	20 (46.5)	46 (46.0)
Both	66 (46.2)	19 (44.2)	47 (47.0)
Number of treatments between admission and delivery
Mean ± SD	2.5 ± 2.0	2.9 ± 2.3	2.3 ± 1.9
Median (range)	2 (1,12)	2 (1,12)	2 (1,12)

Data are n(%) unless otherwise specified.

Time from admission to delivery was significantly different between the matched groups, with an average of 9.5 ± 8.10 days among AQ/AP patients and 7.0 ± 7.54 days for control patients (Table 4, Fig. 2). This mean difference of 2.5 days (95% CI: 0.81–4.26) corresponds to a standardized effect size of 0.324 (and a 0.292 effect size on the matched pairs’ difference). The average GA at delivery was 0.4 weeks longer (95% CI: 0.10–0.62) in the AQ/AP group compared to the control group and was also statistically significant (Table 4, Fig. 2). For GA at delivery, the standardized effect size was 0.149, which was effectively a 0.275 effect size on the matched pairs’ difference.

Table 4.

Primary Outcome Measures for Matched Acupuncture/Acupressure and Control Patients with Preeclampsia

Primary outcomes	Control	Acupuncture/ acupressure	p-value	Difference in means	95% CI for the difference
Days from admission to delivery	7.0 ± 7.54	9.5 ± 8.10	0.004^a	2.5	(0.81–4.26)
Median (range)	4.6 (1.5, 46.3)	6.8 (1.4, 45.8)	0.003^b
Gestational age at delivery, weeks	31.7 ± 2.50	32.1 ± 2.47	0.007^a	0.4	(0.10–0.62)
Median (range)	32.3 (25.1, 7.2)	33.3 (25.0, 34.9)	0.006^b

p-values from the paired t-test.

p-values from the signed rank test.

Data are mean ± SD unless otherwise indicated.

FIG. 2.

Distribution of days from admission to delivery and GA for acupuncture/acupressure (AQ/AP) patients and matched controls. GA, gestational age.

Breakthrough antihypertensive treatment did not significantly differ between the groups when examined in a variety of ways: number of times given in the 12 h after matching time, number of times given between matching time and delivery, and number of times per day medications were given from matching time through delivery (Table 5). Similarly, there were no significant differences for maternal post-delivery LOS or ICU admission or for the neonatal outcomes studied.

Table 5.

Medication Use, Maternal and Neonatal Outcomes for Matched Acupuncture/Acupressure and Control Patients with Preeclampsia

	Control	AQ/AP	Difference	95% CI for difference
Post-match use of breakthrough medications	n = 100	n = 100
Number of times patients received medications within 12 h of match	0.5 ± 0.94	0.4 ± 0.87	−0.1	(−0.37, 0.09)
Number of times patients received medications between time of match and delivery	2.6 ± 3.68	2.6 ± 3.34	0.0	(−0.93, 0.93)
Median (range)	1.0 (0, 18)	1.0 (0, 15)
Number of times/day that patients received medications between match time and delivery	1.4 ± 2.00	1.1 ± 1.86	−0.3	(−0.79, 0.27)
Median (range)	0.5 (0, 9.7)	0.3 (0, 10.2)
Maternal outcomes	n = 100	n = 100
Post-delivery length of stay	3.8 ± 1.44	4.1 ± 1.60	0.3	(−0.13, 0.67)
ICU admission during delivery	8 (8.0)	2 (2.0)	−6	(−12.1, 0.1)
Neonatal outcomes^a	n = 114	n = 114
5-minute Apgar score	8.02 ± 1.34	8.02 ± 1.18	0.0	(−0.33, 0.33)
Birthweight (grams)	1596.2 ± 586.43	1684.3 ± 615.80	88.1	(−68.86, 245.03)
Small for gestational age	34 (34)	36 (36)	2	(−11.10, 14.60)

Data are shown as mean ± standard deviation or n(%).

Neonatal outcomes were analyzed as two independent samples since neonates were not matched.

AQ/AP, acupuncture/acupressure.

Examination of maximum AST and creatinine values over pre-match vs. post-match time windows showed no significant differences (Table 6). Among the controls, maximum MAP increased slightly using both the 12- and 4-h windows pre-match to the 12- and 4-h windows post-match, while the AQ/AP group experienced decreases in maximum MAP (Table 6). Neither of these differences was significant. Changes in minimum platelet counts were significantly different between the groups, with the control group showing a small increase of 0.2 (from a mean of 199.8 ± 71.03 to 200.0 ± 66.58), while the AQ/AP group mean minimum values decreased 16 units from 214.0 ± 64.17 to 198.0 ± 53.47.

Table 6.

Biomarker Comparisons by Pre- and Post-Match Windows

Biomarker	Pairs	Control			AQ/AP			Difference in differences	95% CI for difference in differences
Biomarker	Pairs	Pre-match	Post-match	Difference	Pre-match	Post-match	Difference	Difference in differences	95% CI for difference in differences
AST-SGOT (units/liter) window maximum	84	30.1 ± 23.02	37.3 ± 30.61	7.2	30.2 ± 28.55	45.6 ± 60.14	15.4	8.2	(−0.73, 17.0)
Creatinine (mg/dL) window maximum	80	0.8 ± 0.46	0.8 ± 0.49	0.0	0.7 ± 0.12	0.8 ± 0.15	0.1	0.1	(−0.01, 0.11)
Platelet counts (×10⁹/L) window minimum	94	199.8 ± 71.03	200.0 ± 66.58	0.2	214.0 ± 64.17	198.0 ± 53.47	−16.0	−16.2	(−27.0, −5.5)
Mean Arterial Pressure (mmHg)
12-h window maximum	100	113.6 ± 11.5	114.3 ± 13.5	0.7	112.7 ± 10.9	112.4 ± 11.0	−0.3	−1.0	(−4.04, 2.20)
4-h window maximum	71	108.8 ± 11.45	110.5 ± 13.22	1.7	109.1 ± 10.08	108.1 ± 11.78	−1.0	−2.7	(−6.47, 1.12)

DISCUSSION

This study found that patients with preeclampsia with severe features treated with AQ/AP, in addition to standard care, remained pregnant an average of two and a half days longer than matched patients who did not receive AQ/AP, aligning with treatment goals for preeclampsia to increase latency time until delivery. The treatment group also experienced a nonsignificant decrease in maximum MAP in the time periods before and after treatment, while the comparison group experienced an increase. While there was no significant difference in breakthrough antihypertensive use, the decreased MAPs noted post-AQ/AP treatment in the treatment group suggest the prolonged latency period may be associated with improved BP control in patients receiving AQ/AP treatments. Several other secondary outcomes showed no difference between groups, such as ICU admission, post-delivery LOS, neonatal outcomes, and changes in AST and creatinine. Changes in minimum platelet counts showed a significant difference between groups, with a decrease of 16 points in the AQ/AP group. However, post-matching values between the groups were similar.

This study found 2.5 more days from admission to delivery and 0.4 weeks later GA in the AQ/AP group. Only one other study has examined these outcomes in patients with preeclampsia treated with acupuncture. A pilot of 22 patients with preeclampsia compared 11 patients self-selecting acupuncture plus usual care to 11 matched controls with usual care only.²³ The study found no difference in GA at delivery.

This study found no significant difference in breakthrough antihypertensive medication or in changes in maximum MAP using 4- and 12-h windows. However, there was a pattern of decreasing MAP in the AQ/AP group that was not present for the control group. The pilot of 22 patients with preeclampsia²³ found no difference in the primary outcomes of systolic or diastolic BP immediately after treatment. However, patients in the acupuncture group did have lower BP averages at delivery and postpartum relative to controls. That study did not discuss medication use. A different case study documented acupuncture treatments for a patient admitted with preeclampsia with severe features and HELLP syndrome at 27 weeks 6 days gestation. Initial hospitalization with frequent acupuncture treatments resulted in normalized BP and discharge after 2 weeks. A subsequent hospitalization a week later resumed acupuncture, with the patient reporting symptom reduction after treatments and a reduction in BP spikes.²⁸

Studies of acupuncture in non-pregnant populations have shown that acupuncture is associated with BP reductions.^9–15 Extrapolation from those studies suggests that acupuncture may affect BP and inflammation through the neuroendocrine system, the vascular endothelium, the renin-angiotensin-aldosterone system, and by reducing oxidative stress.^29,30 Another suggestion is that acupuncture may influence BP through efferent nerves, like the sympathetic and vagus nerves.³¹

This study explored the association of AQ/AP with measures of hepatic and renal function. These analyses found no significant difference in maximum values of AST or creatinine. An examination of differences in minimum platelet counts found a decrease in the AQ/AP group only. However, the two groups were similar on post-match values. No other studies have examined these outcomes in patients with preeclampsia. Acupuncture has demonstrated positive outcomes for liver and kidney disease, not specific to pregnancy, including improving liver functions and alleviating the clinical symptoms for cirrhosis,²¹ and nonalcoholic fatty liver disease.²⁰ In addition, acupressure may reduce essential hypertension and lower levels of proteinuria for people with early diabetic nephropathy.¹⁸

While the observed prolongation in latency in this study may not have a significant clinical impact on maternal care, this could impact neonatal outcomes in preeclampsia diagnosed at the extremes of viability. In addition, the proposed mechanism of action of improved BP control may be more clinically relevant for patients for whom severe hypertension is the primary manifestation of preeclampsia. While further research is required to determine the applicability of acupuncture or acupressure to a broad population of patients with preeclampsia, this study suggests that patients with preterm preeclampsia with severe features, especially those with severe hypertension, may benefit from the integration of acupuncture or acupressure into routine clinical care.¹⁸

As this is a retrospective observational study, there are several potential biases and unanswered questions that would be best addressed in the future through a randomized controlled trial design. Standardized timing of both AQ/AP treatments and measurements of MAP and hepatic and renal lab values would enable shorter windows of measurement between treatment and biomarker measurement. Future studies could also examine any differences between acupuncture and acupressure.

This observational retrospective study using EHR data had a larger sample size than previous studies. An additional strength was integrative health care offered to all antepartum patients, reflecting the accessibility of AQ/AP to all inpatients. In addition, the hospitals included in this study are part of a large health system that manages preeclampsia consistent with national guidelines. The matching methodology is another key strength of this study, which aimed to both incorporate timing from admission to treatment to address irregular timing of treatment initiation and usual care standards and minimize confounding.

Limitations included potential selection bias (patients elected to receive or decline acupuncture or acupressure) and irregular and sometimes delayed timing of AQ/AP treatment initiation. Losing 43 of the treated patients may have introduced selection bias toward the null (i.e., bias to find no difference in latency period between AQ/AP and control), as most of the AQ/AP patients who were excluded had longer hospitalization times with no controls available. Patients in the acupuncture group received between 1 and 12 treatments which represents considerable heterogeneity in treatment exposure. The retrospective nature of the study also limited analysis capabilities to measures available in the record, which meant measuring changes in MAP and hepatic and renal lab values immediately after treatments or at regular intervals was not possible.

CONCLUSIONS

The addition of AQ/AP to standard care for patients with preeclampsia with severe features <34 weeks was associated with a statistically significantly longer latency period in this observational study. The mechanism of action and potential association with BP and hepatic and renal function need further examination.

Footnotes

AUTHORS’ CONTRIBUTIONS

A.S.: Conceptualization, data curation, funding acquisition, investigation, methodology, project administration, supervision, writing—original draft. Z.K.: Conceptualization, funding acquisition, writing—original draft, writing—review and editing. A.S.: Data curation, funding acquisition, project administration, writing—original draft, writing—review and editing. S.C.-P.: Data curation, formal analysis, methodology, resources, software, validation, visualization, writing—original draft, writing—review and editing. D.W.: Formal analysis, methodology, software, writing—review and editing. W.W.: Data curation, funding acquisition, writing—review and editing. M.V.: Data curation, methodology. C.B.: Methodology, writing—review and editing. H.T.: Methodology, writing—review and editing. K.L.: Writing—original draft, writing—review and editing. L.C.: Conceptualization, methodology, writing—original draft, writing—review and editing.

AUTHOR DISCLOSURE STATEMENT

No competing financial interests exist.

FUNDING INFORMATION

Funding for this study was granted by the Allina Health Foundation (AHF-22-45).

SUPPLEMENTARY MATERIAL

References

Cameron

, Everitt

, Seegmiller

, et al. Trends in the incidence of new-onset hypertensive disorders of pregnancy among rural and urban areas in the United States, 2007 to 2019. J Am Heart Assoc, 2022; 11(2):e023791; doi: 10.1161/JAHA.121.023791

Center for Disease Control and Prevention. Pregnancy Mortality Surveillance System. 2019. Available from: www.cdc.gov/reproductivehealth/maternalinfanthealth/pregnancy-mortality-surveillance-system.htm [Last accessed: September 30, 2019].

Shih

, Peneva

, Xu

, et al. The rising burden of preeclampsia in the United States impacts both maternal and child health. Am J Perinatol, 2016; 33(4):329–338; doi: 10.1055/s-0035-1564881

Pollock

, Rose

, Dennis

. Pregnant and postpartum admissions to the intensive care unit: A systematic review. Intensive Care Med, 2010; 36(9):1465–1474; doi: 10.1007/s00134-010-1951-0

Mustafa

, Ahmed

, Gupta

, et al. A comprehensive review of hypertension in pregnancy. J Pregnancy, 2012; 2012:105918; doi: 10.1155/2012/105918

Dimes

. Preeclampsia. 2017. Available from: https://www.marchofdimes.org/complications/preeclampsia.aspx# [Last accessed: april, 6].

American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins—Obstetrics. ACOG Practice Bulletin No. 202: Gestational Hypertension and Preeclampsia. Obstetrics & Gynecology, 2019; 133(1):e1–e25; doi: 10.1097/aog.0000000000003018

Magee

, Yong

, Espinosa

, et al. Expectant management of severe preeclampsia remote from term: A structured systematic review. Hypertens Pregnancy, 2009; 28(3):312–347; doi: 10.1080/10641950802601252

Zheng

, Li

, et al. Acupuncture for patients with mild hypertension: A randomized controlled trial. J Clin Hypertens (Greenwich), 2019; 21(3):412–420; doi: 10.1111/jch.13490

10.

Zhao

, Zhou

, Li

, et al. Auricular acupressure in patients with hypertension and insomnia: A systematic review and meta-analysis. Evid Based Complement Alternat Med, 2020; 2020:7279486; doi: 10.1155/2020/7279486

11.

Chen

, Shen

, Tan

, et al. Efficacy and safety of acupuncture for essential hypertension: A meta-analysis. Med Sci Monit, 2018; 24:2946–2969; doi: 10.12659/msm.909995

12.

Niu

, Zhao

, Hu

, et al. Should acupuncture, biofeedback, massage, Qi gong, relaxation therapy, device-guided breathing, yoga and tai chi be used to reduce blood pressure?: Recommendations based on high-quality systematic reviews. Complement Ther Med, 2019; 42:322–331; doi: 10.1016/j.ctim.2018.10.017

13.

Tan

, Pan

, Su

, et al. Acupuncture therapy for essential hypertension: A network meta-analysis. Ann Transl Med, 2019; 7(12):266; doi: 10.21037/atm.2019.05.59

14.

Gao

, Chen

, He

, et al. The effect of auricular therapy on blood pressure: A systematic review and meta-analysis. Eur J Cardiovasc Nurs, 2020; 19(1):20–30; doi: 10.1177/1474515119876778

15.

Biçer

, Ünsal

, Taşcı

, et al. The effect of acupressure on blood pressure level and pulse rate in individuals with essential hypertension: A randomized controlled trial. Holist Nurs Pract, 2021; 35(1):40–48; doi: 10.1097/hnp.0000000000000384

16.

Xiong

, He

, You

, et al. Acupuncture application in chronic kidney disease and its potential mechanisms. Am J Chin Med, 2018; 46(6):1169–1185; doi: 10.1142/s0192415x18500611

17.

Jung

, Lai

, et al. Preserving residual renal function: Is interdialytic acupuncture an add-on option? A case series report. Explore (NY), 2022; 18(6):710–713; doi: 10.1016/j.explore.2022.01.001

18.

Chuang

, Lee

, Lo

, et al. Effect of acupressure at Sanyinjiao on albuminuria in patients with early diabetic nephropathy: A single-blind, randomized, controlled preliminary study. Explore (NY), 2020; 16(3):165–169; doi: 10.1016/j.explore.2019.09.001

19.

, Ho

, Wang

, et al. Acupuncture on renal function in patients with chronic kidney disease: A single-blinded, randomized, preliminary controlled study. J Altern Complement Med, 2017; 23(8):624–631; doi: 10.1089/acm.2016.0119

20.

, Fang

. Research progress on the mechanism of acupuncture treatment for nonalcoholic fatty liver disease. Gastroenterol Res Pract, 2022; 2022:5259088; doi: 10.1155/2022/5259088

21.

, Li

, Xu

, et al. Acupuncture for the treatment of liver Cirrhosis: A meta-analysis. Gastroenterol Res Pract, 2020; 2020:4054781; doi: 10.1155/2020/4054781

22.

Draz

, Serry

ZMH

, Rahmy

, et al. Electroacupuncture versus aerobic interval training on liver functions in patients with nonalcoholic fatty liver. J Altern Complement Med, 2020; 26(1):51–57; doi: 10.1089/acm.2019.0182

23.

Zeng

, Liu

, Luo

, et al. Effects of acupuncture on preclampsia in Chinese women: A pilot prospective cohort study. Acupunct Med, 2016; 34(2):144–148; doi: 10.1136/acupmed-2015-010893

24.

Hypertension in pregnancy. Report of the American College of Obstetricians and gynecologists’ task force on hypertension in pregnancy. Obstet Gynecol, 2013; 122(5):1122–1131; doi: 10.1097/01.Aog.0000437382.03963.88

25.

Deadman

PA-KM

, Baker

. A Manual of Acupuncture. Journal of Chinese Medicine Publications: East Sussex, England; 2016.

26.

. Propensity score matching with time-dependent covariates. Biometrics, 2005; 61(3):721–728; doi: 10.1111/j.1541-0420.2005.00356.x

27.

Team RC. R: A Language and Environment for Statistical Computing. An Academic publisher: Vienna; 2022.

28.

Kocher

, Hobbs

. Integrating acupuncture for preeclampsia with severe features and HELLP syndrome in a high-risk antepartum care setting. Med Acupunct, 2019; 31(6):407–415; doi: 10.1089/acu.2019.1399

29.

Hisamitsu

, Ishikawa

. Changes in blood fluidity caused by electroacupuncture stimulation. J Acupunct Meridian Stud, 2014; 7(4):180–185; doi: 10.1016/j.jams.2014.04.008

30.

Fan

, Yang

, Wang

, et al. The hypotensive role of acupuncture in hypertension: Clinical study and mechanistic study. Front Aging Neurosci, 2020; 12:138.

31.

Lim

H-D

, Kim

M-H

, Lee

C-Y

, et al. Anti-inflammatory effects of acupuncture stimulation via the vagus nerve. PLoS One, 2016; 11(3):e0151882.