Objective
In 2017, the American College of Cardiology and the American Heart Association classified “stage 1 hypertension” as blood pressure (BP) of 130 to 139/80 to 89 mm Hg in nonpregnant adults. However, the American College of Obstetricians and Gynecologists (ACOG) considers the BP cutoff of 140/90 mm Hg to be classified as “hypertension during pregnancy.” We analyzed a large, diverse obstetrical database to determine whether stage 1 hypertension of pregnancy (SOHP) is independently associated with adverse maternal and newborn outcomes.
Study Design
This was a secondary analysis of the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-Be (nuMoM2b) database. The nuMoM2b database includes validated data from 9290 nulliparas with singleton pregnancies receiving prenatal care across 8 centers in the United States who participated in a prospective cohort study sponsored by the Eunice Kennedy Shriver National Institute of Child Health and Human Development. The patients had 3 visits: at gestational age 6 to 13, 16 to 21, and 22 to 29 weeks. We performed a secondary analysis to explore the outcomes between women with SOHP and women with normal BP.
In the study group, we included women with at least 1 BP in the range of 130 to 139/80 to 89 mm Hg (SOHP). In the control group, we included women with BPs below 130 to 139/80 to 89 mm Hg in each visit. We excluded patients with chronic hypertension as defined by a BP ≥140/90 mm Hg before 20 weeks of gestation or at least 1 BP value ≥140/90 mm Hg during any study visit. Furthermore, we excluded women with chronic kidney disease or pregestational diabetes mellitus, women that delivered before 22 weeks of gestation or after 41 weeks of gestation, and women diagnosed with preeclampsia before delivery admission.
We compared baseline characteristics and maternal and newborn outcomes between pregnant women with SOHP and pregnant women with normal BP.
The maternal composite outcome of interest was defined as the occurrence of 1 or more of the following events at 36 to 41 weeks of gestation: preeclampsia or eclampsia; hemolysis, elevated liver enzymes, low platelet count (HELLP) syndrome; maternal death; placental abruption; postpartum hemorrhage; cesarean delivery; and preterm delivery (36–37 weeks of gestation).
The neonatal composite outcome was defined as the occurrence of one or more of the following events: stillbirth, infant death, neonatal morbidity, Apgar score at 5 minutes of life of <7, neonatal intensive care unit admission, small for gestational age, or umbilical artery pH of <7.05 at birth.
For details of the definition of the outcomes, we refer the reader to the official presenting article of the Data Analytics for Safe Healthcare database by the National Institutes of Health.
Statistical analysis was performed using the SPSS software (version 27.0; IBM Corp, Armonk, NY). The continuous variables were presented as median (interquartile range). The categorical variables were presented as number/total number (percentage). The chi-squared test was used for categorical variables, and the Mann-Whitney U test was used for continuous variables. We compared the maternal and neonatal outcomes between the 2 groups with univariate and multivariate analyses. The relative association between SOHP and adverse maternal and neonatal outcomes was quantified using a risk ratio: the risk of an adverse outcome in patients with SOHP vs the risk of an adverse outcome in patients with a normal BP.
Results
We reported the baseline characteristics of the study population in Table 1 . Selected maternal and newborn outcomes are presented in Table 2 . Of 9290 patients overall, 8152 met our inclusion criteria. Of note, 32.3% of patients with normal BP had an adverse maternal outcome, and 16.9% of patients with normal BP had an adverse neonatal outcome. Furthermore, 42.9% of patients with SOHP had an adverse maternal outcome, and 21.7% of patients with SOHP had an adverse neonatal outcome.
| Characteristic | Normal BP (n=6470) | SOHP (n=1682) | P value |
|---|---|---|---|
| Age (y) | 27 (22–31) | 27 (23–31) | .653 |
| BMI (kg/m 2 ) | 23.8 (21.6–27.1) | 28.8 (24.1–34.4) | <.001 |
| Race | |||
| White | 3897/6467 (60.3) | 1102/1682 (65.5) | <.001 |
| Black | 780/6467 (12.1) | 249/1682 (14.8) | |
| Hispanic | 1185/6467 (18.3) | 206/1682 (12.2) | |
| Asian | 294/6467 (4.5) | 33/1682 (2.0) | |
| Other | 311/6467 (4.8) | 92/1682 (5.5) | |
| Gravidity = 1 | 4822/6470 (74.5) | 1264/1682 (75.1) | .602 |
| Smoking | 1095/6470 (16.9) | 315/1682 (18.7) | .081 |
| Public insurance | 1857/6470 (28.7) | 416/1682 (24.7) | .001 |
| Education | |||
| Less than high school graduate | 535/6461 (8.3) | 114/1682 (6.8) | <.001 |
| High school graduate or General Educational Diploma | 729/6461 (11.3) | 213/1682 (12.7) | |
| Some college | 1204/6461 (18.6) | 367/1682 (21.8) | |
| Associate or technical degree | 617/6461 (9.5) | 189/1682 (23.0) | |
| Completed college | 1843/6461 (28.5) | 430/1682 (21.9) | |
| Degree work beyond college | 1533/6461 (23.7) | 369/1682 (21.9) | |
| How will you rate your ability to speak and understand English? | |||
| Very well | 5908/6279 (94.1) | 1632/1681 (97.1) | <.001 |
| Well | 262/6279 (4.2) | 39/1681 (13.0) | |
| Not well | 80/6279 (1.3) | 6/1681 (7.0) | |
| Not at all | 29/6279 (0.5) | 4/1681 (0.2) | |
| Total family income for the past 12 mo (USD) | |||
| <30,000 | 188/3271 (5.74) | 36/8734 (4.10) | <.001 |
| 30,000–99,999 | 1137/3271 (34.7) | 397/873 (45.4) | |
| 100,000–199,999 | 1407/3271 (43.0) | 370/873 (42.3) | |
| ≥200,000 | 539/3271 (16.4) | 70/873 (8.0) | |
| Are you currently living with your partner? | |||
| Yes | 5023/5931 (84.6) | 1340/1583 (84.6) | .967 |
| Gestational diabetes mellitus | 116/6261 (1.9) | 43/1679 (2.6) | .114 |
Stay updated, free articles. Join our Telegram channel
Full access? Get Clinical Tree
