When body tissues are injured, the body uses two main ways to fix the damage: regeneration and repair. Regeneration means replacing damaged cells with the exact same type of cells, so the tissue goes back to looking and working just like it did before. This happens best in tissues where cells divide often, like the skin surface or the lining of the gut.
Repair, on the other hand, happens when the original cells cannot grow back. In this case, the body fills the gap with fibrous connective tissue, forming a scar. While a scar holds the tissue together and restores strength, it does not work quite the same as the original tissue—for example, scar tissue in the heart muscle cannot contract. Understanding this difference helps midwives evaluate how surgical incisions or perineal tears will heal over time.
Healing starts the exact moment an injury occurs. The first step is hemostasis, designed to stop bleeding quickly. Blood vessels constrict, and platelets clump together with fibrin strands to form a stable blood clot, sealing the broken vessel.
Following hemostasis, the inflammatory phase kicks in within minutes. Blood vessels temporarily widen and become leaky, allowing white blood cells—specifically neutrophils and later macrophages—to enter the wound. These cells clean up the area by eating bacteria, foreign debris, and dead tissue. Signs of this phase include redness, heat, swelling, and pain around the wound site. Without this cleanup crew, the wound cannot move forward to grow new tissue.
Once the wound is clean, the proliferation phase begins, usually lasting from day three up to about three weeks. During this time, the body focuses on rebuilding the structure.
The final stage of healing is the remodeling phase, which can last for several months or even up to two years. Even though the wound looks closed, the tissue is still vulnerable.
During remodeling, random clumps of collagen laid down earlier are broken down and replaced with stronger, neatly organized fibers aligned along lines of tension. At the same time, many of the extra blood vessels that formed during proliferation fade away, which causes the scar to slowly change from red and raised to pale and flat. The tensile strength of the wound increases steadily during this time, though a healed scar usually only reaches about 80% of the strength of the original unbroken skin.
Wounds heal in different ways depending on how much tissue was lost and whether the edges can be brought together.
| Healing Type | Description | Common Example | Scar Formation |
|---|---|---|---|
| Primary Intention | Wound edges are neatly brought together (closed with sutures, staples, or clips). Minimal tissue loss. | Clean surgical incision, minor clean cut | Minimal, fine scar |
| Secondary Intention | Wound is left open and heals from the bottom and sides up. Extensive tissue loss or infection. | Deep pressure ulcer, untreated abscess, gaping tear | Larger, more noticeable scar |
Secondary intention healing takes much longer because the body has to fill a wider gap with granulation tissue and rely heavily on wound contraction.
Several local and systemic factors can slow down or completely disrupt the normal healing process. Midwives must watch out for these issues in pregnant and postpartum women.