Neutrophils are white blood cells produced in the bone marrow. They act as first responders, combating foreign invaders. As the most abundant type of white blood cell, they make up 55% to 70% of the total white blood cell count. Elevated neutrophil counts are a common and expected occurrence during pregnancy.
The Role of Neutrophils in Pregnancy
The body naturally increases neutrophil production as a normal adaptation to pregnancy. This rise is due to the physiological stress pregnancy places on the body. Neutrophil counts begin to increase around the second month of pregnancy and generally plateau in the second or third trimester. While typical white blood cell counts for non-pregnant adults range from 4,500 to 11,000 cells per microliter, during pregnancy, this count can increase to 13,200 to 15,900 neutrophils per microliter.
This increase in neutrophils is a compensatory mechanism, strengthening the non-specific immune response to protect both the mother and the developing fetus from infections. Neutrophils in pregnant women also exhibit enhanced phagocytic activity, meaning their ability to engulf and destroy pathogens is heightened. Additionally, these cells contribute to placental development and help maintain maternal-fetal tolerance, which is the mother’s immune system accepting the fetus. After delivery, neutrophil counts typically decrease to around 12,620 per microliter after a vaginal birth and 12,710 after a C-section.
Medical Conditions Leading to Elevated Neutrophils
Beyond the normal physiological changes of pregnancy, several medical conditions can lead to elevated neutrophil counts. Infections are a common cause, particularly bacterial infections, as neutrophils are actively recruited to the site of infection. This includes conditions like urinary tract infections (UTIs) or respiratory infections. When an infection is present, the body’s inflammatory response can cause immature neutrophils, known as band neutrophils, to be released from the bone marrow into the bloodstream.
Inflammatory conditions can also cause an increase in neutrophils, as these cells are part of the body’s general immune response to inflammation. For instance, preeclampsia, a condition that typically develops in the third trimester and involves a sudden rise in blood pressure, is associated with elevated neutrophil counts due to an increased inflammatory response. Neutrophil counts are significantly higher in women with severe preeclampsia compared to those with mild preeclampsia or normal pregnancies. In some cases, elevated neutrophil levels in the first or second trimester might even serve as a predictor for the later development of preeclampsia or gestational diabetes.
Appendicitis, though less common, is another condition that can cause elevated neutrophil levels during pregnancy. In pregnant patients suspected of having appendicitis, an elevated white blood cell and neutrophil count are often observed. A “left shift,” indicating an increase in immature neutrophils (band cells), along with a neutrophil percentage greater than 70%, can be highly indicative of appendicitis. Physical or emotional stress, such as from fever, injury, or surgery, can also lead to increased neutrophil counts, as the body responds to stress.
When to Seek Medical Advice
While an elevated neutrophil count is often a normal part of pregnancy, it is important to discuss blood test results with a healthcare provider. They can interpret the results in the context of individual health and pregnancy progression. A healthcare team regularly monitors white blood cell counts during pregnancy to detect any signs of infection or inflammation.
If elevated neutrophil levels are accompanied by symptoms, further medical attention may be warranted. Symptoms that could indicate an underlying issue include fever, swelling, unexplained bruising or bleeding, persistent fatigue, weakness, night sweats, or unintentional weight loss. These symptoms, especially when combined with significantly high neutrophil counts, might prompt a doctor to order additional tests, such as urine analysis, blood cultures, or imaging studies, to determine the exact cause.