Twins measuring 1 week apart

Cynthia • Cora Jane 💗

So I am 14 weeks pregnant today with di/di twins according to my LMP. I went to my OB today for a regular ultrasound/checkup. Twin A is measuring right on track with a heartbeat of 147. Twin B is measuring exactly 1 week behind with a heartbeat of 126 but was sleeping/ yawning the whole time during the ultrasound. Does that affect their heart rate? also has anybody had twins measure a week apart? I’m nervous because they are sending me to a twin specialist 😭 I just want my babies to be okay!