There are several big changes taking place inside a woman’s body during pregnancy, many of which are necessary to accommodate a growing baby. Most of us are very familiar with some of the more obvious ones – such as elevated hormone levels and increased blood flow – but there is also a lesser-known change that happens when a woman becomes pregnant: she may experience a decreased platelet count.
Platelets are the cells that help blood clot when it needs to. This is especially important during pregnancy because clotting prevents excessive bleeding during and immediately following birth. A decrease in platelets during pregnancy is extremely common, and it is thought to be due to the extra blood volume causing platelets to become diluted, resulting in fewer platelets per milliliter of blood.
While the platelet count for non-pregnant women is around 273,000 per cubic millimeter, it drops to around 251,000 per cubic millimeter for women with uncomplicated pregnancies, according to a recent study at the University of Oklahoma Health Sciences Center in Oklahoma City. While it was previously thought that this platelet decline happened in the mid-second to third trimester of pregnancy, researchers found that pregnant women actually experience a decreased count as early as the first trimester.
For most pregnant women, a slightly lower than normal platelet count is nothing to be concerned about and won’t cause any issues for either mom or baby. A small percentage of women – around 10 percent – even experience a larger drop (below 150,000 platelets per cubic millimeter). This indicates a disorder called gestational thrombocytopenia, and while it sounds scary, it is actually not associated with any maternal or fetal risks and doesn’t require any interventions, other than periodic monitoring. It should be noted, however, that anyone who suspects this disorder should see a doctor to rule out infections of the kidneys, cancer, or other abnormalities.
When the count dips below 100,000 platelets per cubic millimeter, however, experts from the study agree that there is likely an alternative cause or condition other than pregnancy and its complications, such as lupus or other immune disorders, and should be followed closely.