Fetal Development at 7 Weeks

Week 7 Gestational Age (Fetal Age 5 weeks)

Generally from 6 ½ -7 weeks is the time when a heartbeat can be detected and viability can be assessed. A normal heartbeat at 6-7 weeks would be 90-110 beats per minute. The presence of an embryonic heartbeat is an assuring sign of the health of the pregnancy. Once a heartbeat is detected, the chance of the pregnancy continuing ranges from 70-90% dependent on what type of ultrasound is used. If the embryo is less than 5mm CRL, it is possible for it to be healthy without showing a heartbeat, though a follow up scan in 5-7 days should show cardiac activity.

If your doctor is concerned about miscarriage, blighted ovum, or ectopic pregnancy, the gestational sac and fetal pole (if visible) will be measured to determine what type of development should be seen. The guideline is that if the gestational sac measures >16-18mm with no fetal pole or the fetal pole measures 5mm with no heartbeat (by vaginal ultrasound), then a diagnosis of miscarriage or blighted ovum is made. If the fetal pole is too small to take an accurate measurement, then a repeat scan should be done in 3-5 days. If there is absence of a fetal pole, then further testing should be done to rule out the possibility of an ectopic pregnancy.

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