Why am I losing my eyebrows

So just like my other two pregnancies my hair is fuller and growing faster. My nails are stronger and longer so I dont understand why my eyebrows are thinning. I have always had to darken them because i have light colored hair so my eyebrows are almost blonde but they were full and I plucked them to keep them shaped. In the last 2 months they are thinning a lot and at the end of my right eyebrow there is even a spot that has completely fallen out. I know what alopecia is. My husband has is and I've had him look to see if its happening to my hair on my head too and it's not. I'm not having this problem anywhere else on my body except my eyebrows and it seems that the right one is thinning more than the left but they are both noticeably thinner. Idk maybe they will fill back in after i have the baby but it does worry me a little. Anyone else ever had this happen to them?