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Research & Innovation


Clinical Trials

SLUHN 2018-18

A Pragmatic Multicenter Randomized Clinical Trial (RCT) of Antihypertensive Therapy for Mild Chronic Hypertension During Pregnancy: Chronic Hypertension and Pregnancy (CHAP) Project

Physician & Study Coordinator


Joseph Bell, MD

Joseph Bell, MD

Study Coordinator

Susan Hahn




Synopsis: We are asking you to take part in a research study. This study will evaluate the safety and benefits of treating mild chronic hypertension (CHTN), or high blood pressure, during pregnancy.  CHTN is high blood pressure that occurs before pregnancy or during the first half of pregnancy and persists after pregnancy. Compared to women without CHTN, studies show CHTN is strongly associated with a number of bad pregnancy outcomes including preeclampsia (high blood pressure or worsening blood pressure in the second half of pregnancy), preterm birth and fetal growth restriction or small for gestational age babies.

Treatment with blood pressure (BP) medicines to a goal blood pressure <140/90 is the general standard of care for the non-pregnant reproductive age population with CHTN. However, it is unclear whether or not pregnant women with CHTN should be treated with BP medications. The American College of Obstetricians and Gynecologists (ACOG) recommends that pregnant women with severe hypertension (BP≥160/105-110) be treated but to not treat (or reasonable to stop if already receiving treatment) for the majority of pregnant women whose CHTN is considered mild (BP<160/105-110). This recommendation is made because there is a lack of evidence that using BP medicine to treat pregnant women with mild CHTN improves pregnancy outcomes; additionally there is some concern that BP medications reduce the blood flow to the baby and causes poor fetal growth. Other experts recommend treatment similar to that given to non-pregnant adults. As a result some doctors use medications to treat pregnant women with mild CHTN while others do not. Limited research information suggests the possibility for treatment of mild CHTN to actually be beneficial. Therefore, we are conducting this study to find out whether treating pregnant women with mild CHTN with blood pressure medicines to lower their blood pressure below 140/90 is safe and beneficial for the mother and baby.




Inclusion Criteria
1. Women with chronic hypertension in pregnancy with new or untreated chronic hypertension, blood pressure 140-159 systolic or 90-104 diastolic OR known chronic hypertension on monotherapy and taking any antihypertensive and blood pressure ≤159/104 (including those with blood pressure <140/90);
2. Singleton; and
3. viable pregnancy <23 weeks of gestation.


Exclusion Criteria
1. Blood pressures prior to randomization ≥160 systolic or ≥105 diastolic (with or without treatment);
2. Patients currently treated with >1 antihypertensive medication (more likely to have severe chronic hypertension);
3. Multi-fetal pregnancy;
4. Known secondary cause of chronic hypertension;
5. High-risk co-morbidities for which treatment may be indicated:
o Class C or higher diabetes mellitus
o Chronic kidney disease - including baseline proteinuria (>300mg/24-hr, p/c ratio >0.3, or persistent 1+ proteinuria*) or creatinine >1.2.
*If a dipstick value at screening is more than trace, a clean catch or catheter urine should be obtained and re-tested by dipstick. If this shows trace or absence of protein, the patient is included. If it again shows 1+ protein, the patient is excluded until a 24-hr urine <300mg/24hr or p/c ratio is <0.3.
o Cardiac disorders: cardiomyopathy, angina, CAD
o Prior stroke
o Retinopathy
o Sickle cell disease;
6. Known major fetal anomaly;
7. Known fetal demise;
8. Suspected IUGR;
9. Membrane rupture or planned termination prior to randomization;
10. Plan to deliver outside the consortium centers (unless approved by the Clinical Coordinating Center) or unlikely to follow-up in the opinion of study staff or previous participation in this trial;
11. Contraindication to labetalol or nifedipine (e.g. know hypersensitivity); and (12) Current substance abuse or addiction (cocaine, methamphetamine) *The minimum age varies by center