diff --git a/src/npc/surgery/surgery.js b/src/npc/surgery/surgery.js
index 29ea21f03c3f97e8cb86415c9b27a6c844279670..8ff0dde4acf3500b802967907a2d3d7a2f9ce0aa 100644
--- a/src/npc/surgery/surgery.js
+++ b/src/npc/surgery/surgery.js
@@ -563,7 +563,7 @@ globalThis.surgeryAmp = function(slave, part, cheat = false) {
 				slave.drugs = "no drugs";
 			}
 			if (V.menstruation === 1) {
-				this._slave.fertPeak = 1;
+				slave.fertPeak = 1;
 			}
 			surgeryDamage(slave, 20, cheat);
 			break;
diff --git a/src/player/electiveSurgery.js b/src/player/electiveSurgery.js
index 5e9627d4ea006f50dd8d65932cee3b2b589d398b..82366cfb28bd8b469a6fb50da57bb8b95affa0d3 100644
--- a/src/player/electiveSurgery.js
+++ b/src/player/electiveSurgery.js
@@ -3175,7 +3175,7 @@ App.UI.electiveSurgery = function() {
 			V.PC.ovaImplant = 0;
 			V.PC.wombImplant = "none";
 			if (V.menstruation === 1) {
-				this._slave.fertPeak = 1;
+				V.PC.fertPeak = 1;
 			}
 			cashX(forceNeg(50000), "PCmedical");
 		})));
@@ -3194,7 +3194,7 @@ App.UI.electiveSurgery = function() {
 			healthDamage(V.PC, 10);
 			V.PC.preg = 0;
 			if (V.menstruation === 1) {
-				this._slave.fertPeak = 1;
+				V.PC.fertPeak = 1;
 			}
 			cashX(forceNeg(applyDiscount(500)), "PCmedical");
 		})));
@@ -3220,7 +3220,7 @@ App.UI.electiveSurgery = function() {
 				V.PC.ovaImplant = 0;
 				V.PC.wombImplant = "none";
 				if (V.menstruation === 1) {
-					this._slave.fertPeak = 1;
+					V.PC.fertPeak = 1;
 				}
 				cashX(forceNeg(50000), "PCmedical");
 			})));