Irregular heartbeat at 32 weeks

Routine OB appointment today & baby girl's heartbeat was irregular when they checked it on the Doppler. It has always been regular every other appointment, we even got comments on what a good strong heartbeat she had. Anyways, they sent us right away for an ECG and the good news is there was nothing wrong with baby's heart structurally. The doctor said its a pretty common occurance and usually clears itself up before birth or shortly after. My husband made me feel so bad though, he is blaming it on me and the fact that I drink my 2 cups of coffee every morning. I feel like shit and like it's all my fault. I want to just give birth already, being pregnant is becoming so uncomfortable and stressful. 😢