Abstract
Background:
In nonpregnant adults, poor sleep is associated with higher blood pressure. Poor sleep is common in the postpartum period and is often attributed to infant caretaking needs. However, its effects on cardiovascular health in individuals with a hypertensive disorder of pregnancy (HDP) is unknown.
Objective:
To determine the impact of a neonatal sleep intervention on maternal postpartum blood pressure (BP) in individuals with hypertensive disorder of pregnancy (HDP).
Study Design:
In this single institution pilot randomized controlled trial from July 2021 to March 2022, 110 individuals with HDP were randomized to receive a neonatal sleep intervention (SNOO responsive bassinet) plus usual care of safe sleep education (n=54) or usual care alone (n=56). Remote follow-up visits were conducted at 1 week, 6 weeks, and 4 months postpartum, and involved BP and weights, sleep and mood questionnaires, and self-reported infant and maternal sleep logs. Based on institutional data, the sample size had 80% power to detect a 4.5 mm Hg difference in the primary outcome of mean arterial pressure (MAP) at 6 weeks postpartum.
Results:
Baseline characteristics were similar between the arms. At 1 week postpartum, the intervention arm had lower MAP compared to the control arm (99±10 vs. 103±7 mm Hg, p=0.04), and less antihypertensive medication use (23% vs. 35%, p=0.15). At 6 weeks postpartum, MAP was similar between arms (93±8 vs. 94±8 mm Hg, p=0.54) but there was a lower rate of antihypertensive use in the intervention arm (15% vs. 26%, p=0.19). Scores from maternal sleep and mood questionnaires at 6 weeks postpartum, and self-reported infant and maternal sleep duration at 6 weeks and 4 months postpartum were similar between arms (p>0.05).
Conclusion:
The SNOO responsive bassinet as a neonatal sleep intervention did not result in improved MAP at 6 weeks postpartum after HDP.
Keywords: Hypertensive disorders of pregnancy, Maternal sleep, Neonatal sleep, Postpartum blood pressure, Postpartum hypertension
CONDENSATION
The SNOO responsive bassinet neonatal sleep intervention did not improve maternal mean arterial blood pressure at 6 weeks postpartum after a hypertensive disorder of pregnancy.
INTRODUCTION
Hypertensive disorders of pregnancy (HDP) are associated with an increased risk of future hypertensive and cardiovascular disease,1–6 possibly through shared pathophysiology involving endothelial dysfunction.7 Current interventions focus on blood pressure (BP) control, comorbidity screening, and lifestyle modifications.8–9
The postpartum period is characterized almost universally by sleep disturbances.10–14 Outside of pregnancy, poor sleep is also associated with vascular inflammation, endothelial dysfunction, increased BP, and cardiovascular risk.15–16 During pregnancy, poor sleep is associated with increased risk for preterm birth,17 gestational diabetes mellitus,18 postpartum depression,19 and preeclampsia.20 In individuals with HDP, with known endothelial dysfunction,7 poor postpartum sleep may further exacerbate future cardiovascular risk.
The postpartum sleep disturbances are frequently attributed to around-the-clock infant caretaking.21 Of studies that evaluate the impact of neonatal behavioral interventions on maternal sleep,22 none directly evaluated the effects on maternal BP. However, it seems plausible that neonatal sleep interventions could impact maternal sleep with resultant effects on cardiovascular parameters such as BP, via the aforementioned mechanisms already well-established in a general adult population.
This study aimed to determine the impact of a neonatal sleep intervention, the SNOO responsive bassinet, on postpartum BP following HDP. Preliminary data suggest that the SNOO responsive bassinet may increase infant sleep by 1–2 hours per night.23 We hypothesized that for individuals with HDP, using the SNOO responsive bassinet for their infant would result in lower maternal mean arterial pressure (MAP) at 6 weeks postpartum.
MATERIALS AND METHODS
This was a single institution pilot randomized controlled trial conducted between July 2021 and March 2022 of individuals with HDP, randomized to receive a neonatal sleep intervention (SNOO responsive bassinet) plus usual care of safe sleep education, or usual care alone. The Institutional Review Board approved the study on May 20, 2021. The study was registered with ClinicalTrials.gov (NCT04864249, www.clinicaltrials.gov) on April 28, 2021; the first participant was enrolled July 9, 2021. We adhered to CONSORT guidelines.24 Study data are available upon reasonable request from the corresponding author.
Study Recruitment
Individuals met inclusion criteria if they were ≥18 years old, had a singleton, full-term (≥37 weeks) live birth of a non-anomalous fetus, gestational hypertension or preeclampsia by ACOG criteria,25 enrolled in our institutional remote postpartum BP monitoring program26, and were willing to undergo randomization and use the SNOO responsive bassinet for their infant. Individuals were excluded if they were <18 years old, non-English speaking, had chronic hypertension, pre-gestational diabetes, cardiac disease, kidney disease, or liver disease, had a neonate with an anomaly or other condition requiring prolonged neonatal intensive care unit admission, intended to use the SNOO responsive bassinet prior to study enrollment, were unwilling to be randomized, or were unwilling to use the SNOO responsive bassinet.
Individuals were screened by review of the electronic medical record. Individuals who met criteria were approached during their postpartum admission. If the participant agreed to enroll, final review of the inclusion and exclusion criteria was performed, and if still eligible, the participant was consented and randomized.
Randomization and Sample Size
Randomization occurred via permuted blocks with randomly varying block sizes by a web-based data entry system (RedCap, Nashville, TN, USA). Study staff were blinded to initial participant randomization. Based on data from our institutional remote postpartum BP monitoring program, the mean MAP at 6 weeks (among 1,007 individuals) was 94±8 mm Hg.27 With 1:1 randomization, 2-sided t-test with independent means, a sample size of 100 individuals total (50 per arm) would give an 80% power to detect a 4.5 mm Hg difference in MAP, which we determined to be a clinically significant difference, given that this MAP decrease in our reference population would yield a normal MAP <90 mm Hg.28 We estimated a 10% loss-to-follow-up rate; thus, the study had a planned sample size of 110 individuals.
Enrollment
The electronic health record was reviewed to obtain pregnancy and delivery data. All participants completed an enrollment survey to assess demographic and health information. They were provided an automated upper arm BP cuff (A&D UA-651 [A&D Medical; San Jose, CA, USA], validated by Dabl Educational Trust and the British Society for Hypertension for use in postpartum individuals) and instructed on proper home BP measurement. Participants were also provided an electronic scale (Etekcity EB4887S digital body weight scale [Vesync Co. Ltd., Anaheim, CA, USA]) if they did not already have one. Routine postpartum care included safe infant sleep education via video and handout, participation in an institutionally-standard remote BP monitoring program,26 and a 6-week outpatient postpartum visit.
The SNOO, from Happiest Baby, Inc. (Los Angeles, CA, USA) is a commercially available responsive bassinet. The infant is swaddled in a “SNOO sack” and secured back-down in the bassinet. The SNOO responsive bassinet responds to the infant cries by automatically providing a rhythmic rocking motion and emitting engineered white noise sounds. If the infant does not settle within 3 minutes, the SNOO responsive bassinet shuts off and alerts caregivers for assistance. Caregivers can modify the SNOO responsive bassinet settings, receive alerts, and track infant sleep through the SNOO Smart Sleeper application available for iOS (Apple Inc., Cupertino, CA, USA) and Android (Mountain View, CA, USA) smartphone devices.
Individuals randomized to the intervention arm were provided the SNOO responsive bassinet either at hospital discharge or shipped to their home address. At enrollment, participants were oriented to the set-up and use of the SNOO responsive bassinet and SNOO Smart Sleeper mobile application. They were asked to have their infant sleep in the SNOO responsive bassinet as often as reasonably possible.
Participant Follow-Up and Assessment of Outcomes
Remote follow-up visits were conducted at 1 week, 6 weeks, and 4 months postpartum. The 1-week postpartum visit consisted of BP and weight from data from the postpartum remote monitoring program, a postpartum office visit by the participants’ obstetrical care provider, or study staff phone outreach to participants.
The 6-week postpartum visit was conducted remotely via video or phone and included BP and weight, sleep and mood questionnaires, and self-reported infant and maternal sleep duration. BP was measured in triplicate with the study-provided BP cuff, with the mean of three measures used in analysis. MAP was calculated with the formula [systolic BP+(2*diastolic BP)]/3. The mean of three weight measurements was also used in the analysis.
The questionnaires included the Pittsburgh Sleep Quality Index (PSQI), PROMIS Sleep Disturbance Questionnaire, Epworth Sleepiness Scale (ESS), Edinburgh Postnatal Depression Scale (EPDS), Generalized Anxiety Disorder 2-Item (GAD-2), Perceived Stress Scale 4 (PSS-4), and Breslau 7-Item (Breslau-7). Details of these questionnaires are included in the Supplemental Information. Information on the participant’s current health status, medications, and SNOO responsive bassinet use was also collected. Participants were also asked to record their infant and maternal sleep times on a study-provided sleep log for the 7 days preceding this 6-week postpartum study visit. Data was extracted on the infant’s total daily sleep time and longest daily sleep duration; and on the maternal daily time resting but not sleeping, total daily sleep time, and longest daily sleep duration.
Finally, the 4-month postpartum visit was conducted remotely via video or phone and included BP and weight, plus additional questions on participants’ current health status, medications, and SNOO responsive bassinet use. Participants were again asked to record their infant and maternal sleep times on a study-provided sleep log for the 7 days preceding this study visit; sleep data from the logs were abstracted as described above. Participants in the intervention arm were requested to return their SNOO after study completion and by latest at 6 months postpartum.
For participants who were lost to follow-up and did not complete one or more of the study follow-up visits, data on BP, weight, postpartum medication usage, and infant feeding method were abstracted from the electronic medical record, but this was not used in the primary analysis.
Statistical Analysis
Statistical analysis was performed using the intention-to-treat principle, with all randomized subjects included in the analysis. Statistical analyses were performed using Stata (StataCorp LLC, version 17.0, College Station, Texas, USA). The primary outcome was MAP at 6 weeks postpartum, compared between the intervention and control arms. Pre-specified secondary outcomes included MAP at 1 week and 4 months postpartum; systolic and diastolic BP at 1 week, 6 weeks, and 4 months postpartum; antihypertensive medication use at 1 week, 6 weeks, and 4 months postpartum; Stage 1 hypertension or greater or antihypertensive medication use at 1 week, 6 week, and 4 months postpartum, with Stage 1 hypertension defined as a systolic BP of ≥130 and/or or diastolic BP of ≥80; maternal weight and body mass index (BMI) at 1 week, 6 weeks, and 4 months postpartum; subjective sleep quality at 6 weeks postpartum using the PSQI, PROMIS Sleep Disturbance Questionnaire, and ESS questionnaires; objective sleep assessment using infant and maternal sleep logs at 6 weeks and 4 months postpartum; and mood assessment at 6 weeks postpartum using the EPDS, GAD-2, PSS-4, and Breslau-7 questionnaires. Two-sample two-sided t-tests and Mann-Whitney U tests were performed to assess differences between two groups of continuous, normally distributed, and non-normally distributed variables, respectively. Pearson’s chi-square tests or Fisher’s exact tests were performed to assess differences between two groups of categorical variables. An alpha level of 0.05 was set for all statistical analyses.
RESULTS
Between July 2021 and March 2022, 247 individuals were approached, and 110 enrolled in the study, of whom, 54 were allocated to the intervention arm and 56 were allocated to the control arm (Figure 1). Follow-up data was available for 102 (93%) participants at 1 week (mean 8±3 days) postpartum, 104 (95%) participants at 6 weeks (mean 42±5 days) postpartum, and 76 (69%) participants at 4 months (mean 124±13 days) postpartum.
Figure 1:
Participant flow diagram
Baseline demographic and pregnancy characteristics were similar between arms (Table 1). Self-reported ethnicity in the cohort included 3 (3%) Hispanic or Latino individuals. Self-reported race in the cohort included 3 (3%) Asian or Pacific Islander, 20 (18%) Black, 84 (76%) White, and 3 (3%) as none of the above. Forty-seven (43%) of the cohort reported an annual household income of <$75,000, and 30 (27%) of the cohort had public or no insurance in pregnancy. Most (88%) reported an intent to breastfeed. The median gestational age at delivery was 38.1 weeks (inner quartile range [IQR] 37.4–39.1). Fifty-seven (52%), 26 (24%), and 27 (25%) of participants had HDP diagnoses of gestational hypertension, preeclampsia without severe features, and preeclampsia with severe features, respectively, with a mean gestational age of diagnosis at 37.9 weeks (IQR 36.4–39.0).
Table 1:
Demographic and pregnancy characteristics by study arm
| Demographic Characteristic | Control* | SNOO | p value† |
|---|---|---|---|
| n=56 | n=54 | ||
| Age at delivery‡ | 30.5±4.8 | 31.7±5.5 | 0.22 |
| Hispanic/Latino | 2 (4%) | 1 (2%) | 0.58 |
| Self-reported race | 0.34 | ||
| Asian or Pacific Islander | 2 (4%) | 1 (2%) | |
| Black | 10 (18%) | 10 (19%) | |
| White | 41 (73%) | 43 (80%) | |
| None of the above | 3 (5%) | 0 (0%) | |
| Partner status | 0.10 | ||
| Married or partnered | 43 (77%) | 49 (91%) | |
| Separated or divorced | 2 (4%) | 0 (0%) | |
| Single | 11 (20%) | 5 (9%) | |
| Annual household income | 0.20 | ||
| <$75,000 | 26 (46%) | 21 (39%) | |
| $75,000+ | 24 (43%) | 31 (57%) | |
| Prefer not to answer | 6 (11%) | 2 (4%) | |
| Insurance status during pregnancy | 0.32 | ||
| Private | 36 (65%) | 42 (78%) | |
| Public | 17 (30%) | 9 (17%) | |
| Other | 1 (2%) | 1 (2%) | |
| No insurance | 2 (4%) | 2 (4%) | |
| Other children also living at home | 23 (41%) | 25 (46%) | 0.58 |
| Smoking within the past 2 years | 8 (14%) | 6 (11%) | 0.62 |
| Pre-delivery diagnosis of depression | 18 (32%) | 17 (31%) | 0.94 |
| Intent to breastfeed | 49 (88%) | 48 (89%) | 0.82 |
| Gestational age at delivery§ | 38.1 [IQR 37.4–39.2] | 38.1 [IQR 37.3–39.0] | 0.62 |
| Mode of delivery | 0.33 | ||
| Vaginal delivery | 31 (55%) | 35 (65%) | |
| Forceps-assisted vaginal delivery | 1 (2%) | 1 (2%) | |
| Vacuum-assisted vaginal delivery | 3 (5%) | 0 (0%) | |
| Cesarean delivery | 21 (38%) | 18 (33%) | |
| Blood loss during delivery (mL)§ | 300 [IQR 150–500] | 300 [IQR 200–550] | 0.32 |
| Neonatal birthweight (g)§ | 3055 [IQR 2685–3305] | 3155 [IQR 2915–3700] | 0.08 |
| Type of HDP | 0.31 | ||
| Gestational hypertension | 33 (59%) | 24 (44%) | |
| Preeclampsia without severe features | 11 (20%) | 15 (28%) | |
| Preeclampsia with severe features | 12 (21%) | 15 (28%) | |
| Gestational age at HDP diagnosis§ | 37.9 [IQR 36.4–39.1] | 38.0 [IQR 36.4–38.7] | 0.84 |
Data are reported as n (%) unless otherwise indicated
p values indicate the statistical testing result from two-sample t-tests for normally distributed continuous variables, Mann-Whitney U tests for non-normally distributed continuous variables, or Pearson’s chi-squared or Fisher’s exact test for categorical variables
Data are reported as mean±standard deviation
Data are reported as median [IQR]
Maternal BP parameters are depicted in Table 2 and Supplemental Figure 1. MAP, systolic BP, and diastolic BP parameters were similar between arms at all time points except 1 week postpartum, where those in the intervention arm had a lower MAP compared to those in the control arm (99±10 vs. 103±7 mm Hg, p=0.04). The decrease in MAP was driven mostly by a difference in the diastolic BP (83±11 vs. 89±8 mm Hg, p=0.003), where the systolic BP was similar between arms (131±14 vs. 130±10 mm Hg, p=0.89). A per protocol analysis also demonstrated no difference in the primary outcome between arms (p>0.05).
Table 2:
Blood pressure parameters by study arm over time
| Vital Sign Parameter | Control* | SNOO | p value† |
|---|---|---|---|
| n = 56 | n = 54 | ||
| At initial prenatal visit | n = 54 | n = 54 | |
| Mean arterial pressure | 90±8 | 87±7 | 0.05 |
| Systolic blood pressure | 119±9 | 115±10 | 0.09 |
| Diastolic blood pressure | 76±9 | 73±8 | 0.08 |
| On admission to Labor and Delivery | n = 56 | n = 54 | |
| Mean arterial pressure | 102±9 | 103±12 | 0.68 |
| Systolic blood pressure | 135±12 | 140±13 | 0.12 |
| Diastolic blood pressure | 86±10 | 86±13 | 0.78 |
| Enrollment | n = 56 | n = 54 | |
| Mean arterial pressure | 102±11 | 102±8 | 0.78 |
| Systolic blood pressure | 134±14 | 135±12 | 0.77 |
| Diastolic blood pressure | 86±10 | 85±8 | 0.50 |
| On antihypertensive medication(s) at enrollment‡ | 3 (5%) | 4 (7%) | 0.71 |
| On antihypertensive medication(s) at postpartum discharge‡ | 11 (20%) | 9 (17%) | 0.69 |
| 1 week postpartum | n = 49 | n = 53 | |
| Mean arterial pressure | 103±7 | 99±10 | 0.04 |
| Systolic blood pressure | 130±10 | 131±14 | 0.89 |
| Diastolic blood pressure | 89±8 | 83±11 | 0.003 |
| On antihypertensive medication(s)‡ | 19 (35%) | 12 (23%) | 0.15 |
| Stage 1+ HTN or on antihypertensive medication(s)‡ | 44 (85%) | 43 (85%) | 0.84 |
| 6 weeks postpartum | n = 51 | n = 53 | |
| Mean arterial pressure (primary outcome) | 94±8 | 93±8 | 0.54 |
| Systolic blood pressure | 122±11 | 121±10 | 0.55 |
| Diastolic blood pressure | 80±8 | 79±8 | 0.62 |
| On antihypertensive medication(s)‡ | 13 (26%) | 8 (15%) | 0.19 |
| Stage 1+ HTN or on antihypertensive medication(s)‡ | 32 (63%) | 31 (58%) | 0.66 |
| 4 months postpartum | n = 31 | n = 45 | |
| Mean arterial pressure | 94±8 | 93±9 | 0.56 |
| Systolic blood pressure | 122±12 | 121±10 | 0.80 |
| Diastolic blood pressure | 80±7 | 78±10 | 0.48 |
| On antihypertensive medication(s)‡ | 3 (9%) | 3 (6%) | 0.62 |
| Stage 1+ HTN or on antihypertensive medication(s)‡ | 19 (61%) | 21 (47%) | 0.21 |
Data are reported as mean±SD unless otherwise indicated
p values indicate the statistical testing result from two-sample t-tests for normally distributed continuous variables, or Pearson’s chi-squared or Fisher’s exact test for categorical variables
Data are reported as n (%)
At 1 week and 6 weeks postpartum, there was less antihypertensive medication use in the intervention arm (23% vs. 35%, p=0.15 at 1 week postpartum; 15% vs. 26%, p=0.19 at 6 weeks postpartum) (Table 2). The proportion of individuals with Stage 1 hypertension or greater decreased over time but was 53% overall at 4 months postpartum. The difference between arms was not significantly different at any postpartum time point assessed (p>0.05) (Table 2). Weight and BMI parameters were similar between arms at all time points (p>0.05) (Supplemental Figure 2).
Mean scores on the PSQI, PROMIS Sleep Disturbance Questionnaire, and ESS questionnaires at 6 weeks postpartum were similar between arms (p>0.05) (Supplemental Table 1). Most individuals (88%) had a global PSQI score of >5, indicating poor maternal subjective sleep quality, with no significant difference in the proportion of global PSQI scores >5 between arms (90% for the intervention arm vs. 85% for the control arm, p=0.73). There were no statistically significant associations between the maternal sleep quality questionnaire scores and MAP at 6 weeks postpartum (p>0.05) (Supplemental Figure 3a–c).
Maternal and infant sleep assessment from self-reported sleep logs from 6 weeks and 4 months postpartum is shown in Supplemental Table 2. The median infant total daily sleep time and longest daily sleep duration; and the maternal daily time resting but not sleeping, total daily sleep time, and longest daily sleep duration were similar between arms at both timepoints (p>0.05).
Scores on the EPDS, GAD-2, PSS-4, and Breslau-7 at 6 weeks postpartum were similar between arms (p>0.05) (Supplemental Table 3). There were no statistically significant associations between the maternal subjective mood scores and the MAP at 6 weeks postpartum (p>0.05) (Supplemental Figure 4a–d).
DISCUSSION & COMMENT
Principal Findings
In this single institution pilot randomized trial of 110 individuals with HDP, the SNOO responsive bassinet as a neonatal sleep intervention did not result in a difference in the primary outcome of MAP at 6 weeks postpartum. We hypothesized that the SNOO responsive bassinet would lower maternal BP by improving maternal sleep and mood, both known contributors to higher BP in a general population.29 However, we saw no difference in infant sleep, maternal sleep, or maternal mood between arms.
Results
Baseline BP parameters were similar between arms at the initial prenatal visit, Labor and Delivery admission, and postpartum enrollment. However, at 1 week postpartum, the intervention arm had lower MAP compared to the control arm (99±10 vs. 103±7 mm Hg), with this difference driven mostly by the diastolic BP (81±11 vs. 89±8 mm Hg). Antihypertensive medication use decreased over time, and there was a non-statistically significant trend towards lower antihypertensive use at 1 and 6 weeks postpartum in the intervention arm (23% vs. 35% at 1 week postpartum; 15% vs. 26% at 6 weeks postpartum). These secondary outcome findings may not be clinically significant differences, may signal nuanced maternal BP benefits from SNOO responsive bassinet use, or may be secondary to chance; however, this study was underpowered to detect statistical differences therein.
Clinical Implications
We recognize that the SNOO responsive bassinet, at >$1,500 at the time of this writing, is cost-prohibitive for many families. However, equity and access to novel technologies should be priority when evaluating new approaches in research and implementation phases. We hope the FDA De Novo Approval and the possible future classification of the SNOO responsive bassinet as a medical device30–31 may help increase access to individuals of lower socioeconomic status who may be differentially affected by postpartum complications, rather than widen already-existing inequities in postpartum outcomes.32
Research Implications
This study was not powered to understand mechanisms behind potential differences in maternal BP parameters between arms. Nevertheless, an analysis of the secondary outcomes demonstrated that using the SNOO responsive bassinet as a neonatal sleep intervention did not improve maternal subjective sleep quality, infant or maternal objective sleep duration, or maternal subjective mood. Neither self-reported maternal sleep quality nor mood were associated with BP at 6 weeks postpartum. Recent data demonstrates high rates of depression following an HDP,33–35 which could impact postpartum sleep and deserves further study. Future studies would also benefit from objective assessment of maternal or infant sleep, such as by accelerometer.
In addition, the effects of the SNOO responsive bassinet on maternal postpartum BP may not be seen until later postpartum. The last study follow-up was 4 months postpartum, given that Happiest Baby, Inc. recommends weaning from the SNOO responsive bassinet around 4–6 months of age when infants can roll over. Infant sleep patterns also change over the first year.36 Future studies with longer follow-up or targeted evaluation of infant sleep patterns may provide additional clarity.
Strengths and Limitations
A strength of the study was a high rate of study enrollment, with 110 (46%) participants enrolled out of 247 eligible individuals approached. This is important for future studies, as the authors recognize that offering a neonatal sleep intervention during the postpartum admission – when caregivers may already have infant sleeping arrangements planned – is a novel concept. From this pilot study, it seems that individuals are willing to undergo a novel neonatal sleep intervention for possible maternal health benefits.
An additional strength is the randomized study design. The mean MAP at 6 weeks postpartum was 93±8 mm Hg, similar to prior data from our institutional remote postpartum BP monitoring program. The BPs at 1 and 6 weeks postpartum were also similar to previously published data regarding postpartum BP trajectories after HDP,27 suggesting that we captured a representative sample of individuals at our institution affected by HDP. However, results may not be externally generalizable, given the controlled research setting and that decisions regarding infants’ sleep arrangements may be made before HDP onset.
A limitation of our study is the limited published data on the SNOO responsive bassinet’s role on infant sleep parameters. However, we recognize that many parents are interested in the SNOO responsive bassinet given this very purported benefit of improved neonatal sleep. Given the urgent need to identify strategies to improve maternal postpartum cardiovascular health, we designed this study based on this hypothesized mechanism of action.
In addition, given postpartum enrollment, there was a lack of information on important pre-delivery and intrapartum hemodynamic parameters which may have affected postpartum BPs. Furthermore, the choice of antihypertensive initiation and titration was clinician-driven rather than standardized per study guidelines. An additional limitation was participants’ use of automated BP cuffs. Although ambulatory BP is the gold standard for out-of-office assessments,37 this was not feasible in our cohort, nor cost-effective in studying this population. Finally, we were not able to practically assess all potential contributors – such as pain, pre-pregnancy maternal sleeping habits, the role of other infant caretakers, infant feeding methods, etc. – to maternal sleep and cardiovascular health.
Conclusions
This study highlights the ongoing cardiovascular risk after HDP and the urgent need to identify novel strategies to improve maternal BP postpartum. Addressing infant sleep – often a huge focus in the postpartum individual’s life – deserves further exploration to understand the complex relationship between infant sleep, maternal sleep, and postpartum cardiovascular health.
Supplementary Material
AJOG AT A GLANCE.
A. Why was this study conducted?
This randomized trial aimed to determine the impact of a neonatal sleep intervention (SNOO responsive bassinet) on maternal postpartum blood pressure in individuals with hypertensive disorder of pregnancy.
B. What are the key findings?
The SNOO responsive bassinet neonatal sleep intervention did not result in a difference in the primary outcome of mean arterial pressure at 6 weeks postpartum. We also saw no difference in infant sleep, maternal sleep, or maternal mood between the intervention and control arms.
C. What does this study add to what is already known?
To our knowledge, this is the first study designed to study the effect of a neonatal sleep intervention on maternal postpartum blood pressure, representing an innovative approach to improving maternal health in the postpartum period.
FUNDING
The University of Pittsburgh, Department of Obstetrics, Gynecology and Reproductive Sciences, University of Pittsburgh Medical Center Magee-Womens Hospital, and Magee-Womens Research Institute and Foundation provided internal funding for this study. The NIH/ORWH Building Interdisciplinary Research Careers in Women’s Health (BIRCWH) NIH K12HD043441 (to AH) also provided funding support for this study. Happiest Baby, Inc. supplied the SNOO responsive bassinets for this study.
Footnotes
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CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, www.clinicaltrials.gov, NCT04864249
PRESENTATION
The results of this study were presented at the Society for Maternal-Fetal Medicine’s 43rd Annual Pregnancy Meeting held February 6–11, 2023 in San Francisco, CA.
BLINDED CONFLICT OF INTEREST STATEMENT
The authors report no conflicts of interest.
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