Ultrasound Discrepancies in Early Pregnancy: Hope or Concern?

The ultrasound shows that the gestational age is two weeks smaller than the actual gestational age, but there is a heartbeat. Is this a cause for concern?

Hello Dr.
Wu, my husband and I have been using ovulation test strips for family planning.
The first day of my last menstrual period was January 28 (4 weeks), and I tested positive for pregnancy on February 7 (5 weeks and 2 days) with an HCG level of 4180302 (8 weeks and 5 days).
During my first prenatal check-up, the baby had a heartbeat, but the ultrasound showed that the baby was only measuring 6 weeks and 3 days (0.6 cm).
I am very certain about when I conceived and when I tested positive, so I believe I should be 8 weeks along.
However, even though the baby has a heartbeat, it is quite small, and I am very worried.
Initially, the doctor had difficulty locating the baby and mentioned that it was positioned very deeply.
I have been pregnant five times; the first, third, and fourth pregnancies ended in miscarriage, and this is my fifth.
In my last pregnancy, the baby was also measured at 6 weeks in size during the seventh week, and although there was a heartbeat, it ended in miscarriage as well.
I would like to know if I should hold onto too much hope, given that I have experienced three miscarriages.
I am hesitant to dream and feel it is more realistic to prepare for the worst.
Is there a possibility that at my next check-up (in 17 days), the baby could catch up in growth? Are there other mothers who have experienced similar situations? Thank you!

Lente, 40~49 year old female. Ask Date: 2020/03/03

Dr. Wu Xianghui reply Obstetrics and Gynecology

Early pregnancy conditions vary from person to person.
It is recommended to visit an obstetrician for examination and evaluation.

Reply Date: 2020/03/03

More Info

Dear Patient,
Thank you for sharing your concerns regarding your early pregnancy and the discrepancies observed in your ultrasound measurements. It’s completely understandable to feel anxious, especially given your previous pregnancy experiences. Let’s break down your situation and address your questions.

Firstly, it’s important to understand that discrepancies between the gestational age calculated from your last menstrual period (LMP) and the size of the fetus as measured by ultrasound can occur for several reasons. The gestational age is typically calculated based on the first day of your last menstrual period, which assumes a regular 28-day cycle. However, if your cycle is irregular or if ovulation occurred later than expected, this could lead to a difference in the estimated gestational age.

In your case, you mentioned that at 8 weeks and 5 days, the ultrasound showed a fetal size corresponding to only 6 weeks and 3 days. While this can be concerning, it’s crucial to note that the presence of a heartbeat is a positive sign. Generally, the detection of a heartbeat at this early stage indicates that the pregnancy is viable, even if the fetal size is smaller than expected.
Ultrasound measurements can vary due to several factors, including the position of the fetus, the skill of the technician, and the quality of the equipment used. Additionally, fetal growth can sometimes be slower in early pregnancy, but many babies catch up as the pregnancy progresses. It’s not uncommon for a fetus to be smaller than expected in early scans and then grow at a normal rate in subsequent weeks.

Regarding your question about hope versus concern, it’s natural to feel apprehensive, especially after experiencing previous losses. However, it’s also essential to remain optimistic. Many women have had similar experiences where initial ultrasounds showed smaller sizes, but the pregnancies progressed normally. The fact that you have a heartbeat is a reassuring sign.

As for your upcoming appointment in 17 days, there is indeed a possibility that the fetus may catch up in size. Growth rates can vary, and many factors influence fetal development. It’s essential to maintain regular prenatal care and follow your doctor’s recommendations. They will monitor your pregnancy closely and provide guidance based on the ultrasound findings.

In the meantime, try to focus on self-care and maintaining a healthy lifestyle. Proper nutrition, hydration, and rest are vital during this time. If you have any specific concerns or symptoms, such as bleeding or severe cramping, don’t hesitate to reach out to your healthcare provider immediately.

Lastly, consider joining a support group for women who have experienced pregnancy loss. Sharing your feelings and experiences with others who understand can be incredibly helpful.

In conclusion, while it’s normal to feel anxious given your history, the presence of a heartbeat is a positive indicator. Continue to monitor your pregnancy with your healthcare provider, and remember that many women have had successful pregnancies despite initial concerns. Stay hopeful, and take care of yourself during this time.

Best wishes for a healthy pregnancy,
Doctor Q&A Teams

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