What bloodwork and frequency are recommended for a pregnant woman with pre-existing hypertension (high blood pressure)?

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From the Guidelines

For pregnant women with pre-pregnancy hypertension, I recommend comprehensive bloodwork at the first prenatal visit, including a full blood count, liver enzymes, serum creatinine, electrolytes, uric acid, urinalysis, and microscopy, as well as PCR or albumin: creatinine ratio, as outlined by the ISSHP guidelines 1.

Bloodwork Monitoring

The following tests should be performed at the first diagnosis:

  • A full blood count (hemoglobin and platelet count)
  • Liver enzymes (aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase) and functions tests (international normalized ratio, serum bilirubin, and serum albumin)
  • Serum creatinine, electrolytes, and uric acid
  • Urinalysis and microscopy, as well as PCR or albumin: creatinine ratio

Frequency of Bloodwork

Throughout pregnancy, blood pressure should be monitored at each prenatal visit, with bloodwork repeated every trimester (approximately weeks 12,24, and 36) 1. More frequent testing may be needed in the third trimester, typically every 2-4 weeks, including liver function tests, platelet counts, and urine protein-to-creatinine ratio to monitor for preeclampsia 1.

Additional Tests

Additional tests include serum creatinine, blood urea nitrogen, uric acid levels, and 24-hour urine collection for protein if preeclampsia is suspected 1. This monitoring schedule helps detect complications early, as chronic hypertension increases risks of preeclampsia, intrauterine growth restriction, and placental abruption. The frequency may increase with worsening hypertension or development of symptoms like headaches, visual changes, or epigastric pain, which could indicate preeclampsia. Early detection through regular monitoring allows for timely interventions to protect both mother and baby.

Key Principles of Management

The key principles of management of gestational hypertension include controlling blood pressure, monitoring for development of preeclampsia, monitoring fetal growth, and delivery can be delayed until 39+6 weeks provided blood pressure can be controlled, fetal monitoring is reassuring, and preeclampsia has not developed 1.

From the Research

Bloodwork for Pregnant Women with Pre-Pregnancy Hypertension

The following bloodwork is relevant for pregnant women with pre-pregnancy hypertension:

  • Complete Blood Count (CBC) to monitor for any potential hematologic disorders or other medical problems 2, 3
  • Blood pressure monitoring to assess the severity of hypertension and guide treatment decisions 4, 5

Frequency of Bloodwork

The frequency of bloodwork for pregnant women with pre-pregnancy hypertension may vary depending on the individual case and the severity of the hypertension. However, the following general guidelines can be considered:

  • Regular blood pressure monitoring throughout pregnancy 4, 5
  • CBC and other relevant blood tests as needed to monitor for potential complications or to guide treatment decisions 2, 3

Specific Blood Tests

The following specific blood tests may be relevant for pregnant women with pre-pregnancy hypertension:

  • Red blood cell count, hemoglobin, hematocrit, and red blood cell indices to monitor for anemia or other hematologic disorders 2, 3
  • White blood cell count and differential to monitor for infection or inflammation 2, 3
  • Platelet count to monitor for thrombocytopenia or other platelet disorders 2, 3
  • Blood tests to monitor liver and kidney function, as hypertension can affect these organs 4, 5

Treatment and Management

The treatment and management of pre-pregnancy hypertension in pregnant women should be guided by the severity of the hypertension and the presence of any underlying medical conditions. The following general principles can be considered:

  • Non-pharmacological treatment, such as lifestyle modifications, may be considered for mild hypertension 4
  • Pharmacological treatment, such as labetalol or nifedipine, may be considered for more severe hypertension or for women with underlying medical conditions 4, 5
  • Close monitoring of blood pressure and other relevant parameters to guide treatment decisions and prevent complications 4, 5

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

The complete blood count: physiologic basis and clinical usage.

The Journal of perinatal & neonatal nursing, 1997

Research

[Hypertension in pregnancy].

Vnitrni lekarstvi, 2006

Research

Hypertension During Pregnancy.

Current hypertension reports, 2020

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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