Vaginal bleeding may affect as many as 40% of pregnant individuals. Most frequently, it occurs during the first trimester of pregnancy, meaning until week 12, but sometimes it can happen during the second or third trimesters, or between weeks 13 and 27, and weeks 28 to 40, respectively.
The first step when confronted with vaginal bleeding during pregnancy is to assess the hemodynamic stability of the individual, based on the degree of hypovolemia and vital sign status.
Stage 1 hypovolemia is when 500 to 1000 milliliters of blood have been lost. Blood pressure is usually normal, but there may be palpitations, tachycardia and slight dizziness.
Stage 2 is when 1000 to 1500 milliliters have been lost. Systolic blood pressure drops to 80 to 100 mmHg, tachycardia is obvious, and there may be weakness and sweating.
Stage 3 is when 1500 to 2000 milliliters have been lost. Systolic blood pressure drops between 70 and 80 mmHg, and there may be restlessness, pallor and low urine output.
Finally, stage 4 is when more than 2000 milliliters have been lost, systolic blood pressure is less than 70 mmHg, and symptoms may include cardiovascular and respiratory collapse, loss of consciousness and anuria.
Now, before elucidating the cause, some immediate measures should be taken in order to compensate the blood loss. These follow an A-B-C pattern.
A stands for airway, so you’ll want to protect the airway, especially when there’s loss of consciousness.
B stands for breathing, so you’ll want to administer Oxygen through a non-rebreather mask.
C stands for circulation - meaning measuring vital signs and establishing the degree of hypovolemia, inserting two large caliber peripheral IV catheters - of at least 14 gauge or even larger gauge -, and starting fluid resuscitation immediately, with 500 milliliters of normal saline or lactated Ringer’s solution given over 30 minutes.