During pregnancy, your blood volume increases by up to 50%. With a decline in hemoglobin levels and hematocrit (particularly in the last trimester), the platelet count also slightly decreases. However, the white blood cells (WBCs) in the blood increase following pregnancy, termed leukocytosis.
Leukocytes or WBCs are classified as agranulocytes (lymphocytes and monocytes) and granulocytes (eosinophils, neutrophils, and basophils), which make up the body’s immune system and fight against infection (1).
Read this post to know about the causes of high WBC count in pregnancy and the complications associated with this condition.
What Is The White Blood Cell Count During Pregnancy?
Following pregnancy, there is a gradual increase in the normal WBC count (leukocytosis), with a slight shift toward an increased percentage of neutrophils.
|Trimesters||WBC (Leukocyte) count|
|Non-pregnant reference range||4.8–10.8 x 103/mm3|
|First and second trimesters||6–16 x 103/mm3 (3.5 x 103/mm3 increase)|
|Third trimester||20–30 x 103/mm3|
However, several studies have associated leukocytosis in the first trimester with a complicated pregnancy, preeclampsia, and gestational diabetes mellitus (GDM) (3) (4). Therefore, the leukocyte count must be correctly interpreted and correlated during your antenatal visits and postnatal care (1).
What Are The Causes of High WBC Count During Pregnancy?
In general, an increased WBC count indicates (1)
- Acute infection
- Cancer (such as chronic leukemia)
- Overuse of medications such as corticosteroids
However, due to the physiological stress caused by pregnancy, you may have a higher WBC count even in normal pregnancy. Hence, maternal WBC count cannot be a primary screening technique for detecting severe pregnancy complications (5). Conversely, an increased WBC count in your urine sample indicates a urinary tract infection (UTI) (6).
Pregnancy necessitates a complex physiological process where the endocrine system, metabolic processes, and genital system undergo several changes to nourish the developing fetus and prepare the body for labor and delivery. As your pregnancy progresses, this physiological and emotional stress raises your leukocyte count as the leukocytes accept stimulatory impulses (7).
What Does The White Blood Cell Differential Count Indicate In Pregnancy?
During a healthy pregnancy, leukocytosis is generally referred to as an increased percentage of neutrophils in the blood. However, there are many types of WBCs, and elevated levels of other WBCs may imply different diagnoses (1) (8).
- Neutrophils: An increased level of neutrophils (neutrophilia) generally indicates acute bacterial infection, burns, acute stress, leukemia (blood cancer), rheumatoid arthritis, and steroid use. However, neutrophilia is normal during pregnancy due to impaired neutrophilic apoptosis and may not have any clinical significance.
- Eosinophils: Eosinophilia (high eosinophil count) usually indicates the presence of allergic conditions, parasitic infections, and leukemia polyarteritis nodosa autoimmune disease. However, it also decreases with gestational age (mostly in the third trimester).
- Basophils: Basophilia (high basophil count) is generally caused by allergic conditions, chronic myelogenous leukemia, Hodgkin’s disease, and oral contraceptive usage. However, it also decreases as your gestation advances.
- Monocytes: Monocytes are the largest WBCs, and monocytosis (high monocyte count) is generally caused by chronic inflammation, Cushing’s syndrome, viral infection, and bacterial infections such as tuberculosis. During pregnancy, there is an absolute monocytosis, especially in the first trimester, but this reduces as your gestation advances.
- Lymphocytes: Lymphocytosis (high lymphocyte count) is generally caused by viral infections, leukemias, and adrenal insufficiency. However, an increase in the lymphocyte percentage in the WBCs during pregnancy may indicate a bacterial infection.
How To Diagnose High White Blood Cell Count During Pregnancy?
In general, the leukocyte count is measured as part of a complete blood count (CBC) test, a routine test during pregnancy. Your doctor may test your blood for hemoglobin, WBC, and platelet counts in almost every prenatal visit to look for conditions that may complicate the pregnancy (6).
What Are The Signs Of High White Blood Cell Count During Pregnancy?
A high WBC count may not present any symptoms in pregnancy. However, the symptoms of a high WBC count in non-pregnant people usually include (9)
- Bruising/bleeding tendency
- Night sweats
- Weight loss
If you detect any of these symptoms while pregnant, contact your healthcare provider, as it may be a sign of infection or underlying medical complications.
Can A High White Blood Cell Count Cause Miscarriage?
While leukocytosis is common during pregnancy, it could also result from an underlying problem that typical prenatal WBC count tests cannot detect, necessitating extra screening. In the first trimester, higher platelet levels and WBC counts are linked to a higher risk of miscarriage (5) (10).
During pregnancy, your body undergoes various changes, including a higher WBC count in the blood (leukocytosis). While leukocytosis in pregnancy is normal, it can also occur due to infections, dehydration, or pre-existing conditions that may complicate your pregnancy. Therefore, consult your doctor if you experience any unusual symptoms such as fever, night sweats, or allergic reactions during pregnancy.
- David Nzioka Mutua et al.; (2018); Hematological Profile of Normal Pregnant Women.
- Pregnancy: laboratory measurements.
- Bernard J. Canzoneri et al.; (2011); Increased Neutrophil Numbers Account for Leukocytosis in Women with Preeclampsia.
- Tiange Sun et al.; (2020); Elevated First-Trimester Neutrophil Count Is Closely Associated With the Development of Maternal Gestational Diabetes Mellitus and Adverse Pregnancy Outcomes.
- Ivana Musilova et al.; (2017); Maternal white blood cell count cannot identify the presence of microbial invasion of the amniotic cavity or intra-amniotic inflammation in women with preterm prelabor rupture of membranes.
- Routine Tests During Pregnancy.
- Priya Soma-Pillay et al.; (2016); Physiological changes in pregnancy.
- Surabhi Chandra et al.; (2012); Physiological Changes in Hematological Parameters During Pregnancy.
- Lyrad K. Riley and Jedda Rupert; (2015); Evaluation of Patients with Leukocytosis.
- Naser Al-Husban et al.; (2019); Platelet and White Blood Cell (WBC) Counts in the First Trimester and Pregnancy Outcome: Prospective Controlled Study.