Why Does White Blood Cell Count Increase During Pregnancy?

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Why Does White Blood Cell Count Increase During Pregnancy?

Jun 12, 2025

Pregnancy is a time of remarkable transformation. Your body works tirelessly to nurture and protect your new life. Among these changes, you may notice variations in your blood test results, particularly your white blood cell (WBC) count. This is a normal part of the process and not a cause for alarm, even if it may initially cause confusion or concern. At BirthRight by Rainbow Hospitals, we understand that every expecting parent wants the very best for their baby. We are here not just to provide medical care, but also to help you understand and navigate every aspect of your pregnancy with clarity, compassion, and expert care.

What Does An Elevated White Blood Cell Count Mean in Pregnancy?

White blood cells play a crucial role in your immune system. They help defend your body against infections, inflammation, and stress. A mild to moderate WBC count increase is a normal and healthy part of pregnancy, especially in the second and third trimesters. This increase is a protective mechanism. Your immune system adjusts to support both you and your baby, preparing your body to handle minor infections or inflammation without causing harm to the fetus. Think of it as your body staying on high alert to keep you both safe.

Why Does the White Blood Cell Count Increase During Pregnancy?

There are several physiological reasons for this increase:

Hormonal Changes:

Hormones like cortisol (the stress hormone) rise during pregnancy. Cortisol can temporarily boost WBC production, especially neutrophils, which are frontline defenders of your immune system. This means that your body is preparing for potential stressors, such as infections, by increasing the number of cells that can fight them off.

Increased Blood Volume:

As your pregnancy progresses, your blood volume increases to meet the demands of your growing baby. This natural expansion also contributes to the higher count of circulating white blood cells.

Labour and Delivery Preparation:

In the final weeks of pregnancy and during labour, your WBC count may rise sharply, sometimes doubling, due to the physical stress of childbirth. This is entirely expected and not a cause for concern unless accompanied by signs of infection.

When Is It A Concern? High Risk Pregnancy Indicators

While a moderate increase in white blood cells is common and harmless, very high levels or sudden spikes, especially if accompanied by fever, fatigue, pain, or unusual discharge, could indicate an underlying issue such as:
  • Infections (urinary, respiratory, or vaginal)
  • Preeclampsia
  • Autoimmune disorders
  • Blood clotting issues
These could point toward a high risk pregnancy, and early detection is crucial. At BirthRight by Rainbow Hospitals, our multidisciplinary obstetric and fetal medicine teams are equipped to manage these complex scenarios with the highest standard of care and compassion. Your Health Deserves the Best, Always Choosing the right place for pregnancy care can make all the difference. At BirthRight by Rainbow Hospitals, widely regarded as the best hospital for pregnancy, we offer:
  • 24x7 fetal monitoring and diagnostic services
  • High risk pregnancy units with advanced maternal-fetal medicine support
  • Personalized care plans tailored to your and your baby's health
  • On-site pathology labs for real-time blood work interpretation
  • Experienced obstetricians, neonatologists, and hematologists working together to keep you safe
Our approach blends clinical excellence with emotional support, ensuring that you feel heard, informed, and empowered every step of the way.

A Rise in WBCs Is Not Always a Red Flag

If you are pregnant and your blood cell count increases, don't panic. In most cases, it is your body's natural way of strengthening defenses. However, it is always best to consult your doctor if you are unsure or have other symptoms. Remember, the expert and best gynecologists at BirthRight by Rainbow Hospitals are there to support you and ensure the best possible outcome for you and your baby. Our team at BirthRight by Rainbow Hospitals is just a call away, ready to support you through every question and concern. You and your baby deserve only the best and nothing less. For More Information and Appointments, Please Call 1800 2122.

FAQs:

1. Why does white blood cell count increase during pregnancy?

A blood cell count increase during pregnancy is a normal physiological response. It occurs due to hormonal changes, increased blood volume, and your body preparing to protect both mother and baby from potential infections. This rise—especially in the second and third trimesters—is usually harmless and reflects your immune system adapting to support your pregnancy.

2. When should I be concerned about a high white blood cell count during pregnancy?

While a mild rise is typical, a significantly elevated white blood cell count accompanied by symptoms such as fever, fatigue, pain, or unusual discharge may signal infection or another complication. These can be early signs of a high risk pregnancy and should be evaluated by your obstetrician to rule out conditions like urinary tract infections, preeclampsia, or autoimmune disorders.

3. Can a high white blood cell count indicate labor is near?

Yes, nearing labor—especially in the final weeks—can cause a natural blood cell count increase during pregnancy. Your body is preparing for the physical stress of childbirth. As long as this increase isn’t paired with signs of infection or discomfort, it is typically not a cause for concern.

4. Where can I get the safest care if my pregnancy is high risk?

If you're navigating a high risk pregnancy, BirthRight by Rainbow Hospitals is considered the best hospital for pregnancy care. With 24x7 fetal monitoring, advanced diagnostics, experienced maternal-fetal medicine specialists, and on-site lab facilities, we provide safe, expert-led care tailored to your unique needs—ensuring both you and your baby are in the best hands.

Dr. Mathangi Rajagopalan

Senior Consultant – Obstetrics and Gynecology

Rainbow Children's Hospital

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