Fetal Growth Discrepancies: What to Expect at 33 Weeks

Fetal growth issues

Doctor, I am currently 33 weeks pregnant.
The ultrasound shows that the baby's head circumference is at 34 weeks, while the thigh measurement is at 31 weeks.
There is a three-week difference between the head circumference and the thigh measurement.
In the previous ultrasound at 31 weeks, the head circumference was at 32 weeks and the thigh was at 30 weeks, showing a two-week difference.
This time, the difference is one week.
Is this normal?

Ali, 20~29 year old female. Ask Date: 2017/05/27

Dr. Cao Guotao reply Obstetrics and Gynecology

Hello, you should be fine for now; just monitor the situation.
Wishing you good health.

Reply Date: 2017/05/27

More Info

At 33 weeks of pregnancy, it is common for expectant mothers to have concerns about fetal growth discrepancies, especially when ultrasound measurements indicate that different parts of the fetus are measuring at different gestational ages. In your case, the head circumference is measuring at 34 weeks, while the thigh bone (femur) is measuring at 31 weeks. This discrepancy of three weeks can understandably raise questions about the health and development of your baby.

Firstly, it is important to recognize that variations in fetal measurements are not uncommon. Fetuses can grow at different rates in different parts of their bodies, and these variations can be influenced by a number of factors, including genetics, maternal health, and nutritional status. The head circumference is often considered a more reliable indicator of fetal growth and development than the femur length, as the head is less affected by external factors. In many cases, a larger head circumference can indicate that the brain is developing appropriately, while variations in limb length may not be as critical.

The discrepancies you are observing between the head circumference and femur length could be due to several reasons:
1. Genetic Factors: Just like adults, fetuses can inherit traits from their parents that affect their growth patterns. If you or the baby's father have similar growth patterns, this could be a normal variation.

2. Measurement Error: Ultrasound measurements can sometimes vary due to the position of the fetus, the skill of the technician, or the quality of the equipment. Slight differences in measurements taken at different times can occur, and it is essential to consider the overall trend rather than focusing solely on individual measurements.

3. Nutritional Status: Maternal nutrition plays a significant role in fetal growth. Ensuring a balanced diet rich in essential nutrients, including proteins, vitamins, and minerals, can support healthy fetal development. If there are concerns about your nutrition, discussing dietary adjustments with your healthcare provider may be beneficial.

4. Placental Function: The placenta is crucial for delivering nutrients and oxygen to the fetus. If there are concerns about placental function, as indicated in previous discussions about preeclampsia and placental insufficiency, your healthcare provider may recommend additional monitoring or interventions to ensure optimal fetal growth.

5. Follow-Up Monitoring: Regular ultrasounds and check-ups are essential to monitor fetal growth and development. Your healthcare provider may suggest follow-up ultrasounds to track the growth patterns over time. Consistent monitoring can help identify any concerning trends and allow for timely interventions if necessary.

In conclusion, while it is natural to be concerned about discrepancies in fetal growth measurements, it is essential to discuss these findings with your healthcare provider. They can provide personalized insights based on your specific situation and may recommend further monitoring or interventions if needed. Maintaining open communication with your healthcare team and attending all scheduled appointments will help ensure the best possible outcomes for you and your baby. Remember that every pregnancy is unique, and variations in growth can be normal.

Similar Q&A

Understanding Fetal Growth Abnormalities: What to Expect After Early Delivery

Hello doctor, my wife is currently 28 weeks pregnant, but the fetal head circumference and abdominal circumference are at 24 weeks, and the limbs are stagnating at 21 weeks. All prenatal check-up reports indicate normal genetics. Previously, it was noted that there was poor place...

Dr. Cao Guotao reply Obstetrics and Gynecology
Hello, it is recommended to visit a medical center for further evaluation and consult with the physicians there. Wishing you good health.

Understanding Fetal Growth Concerns: What to Know at 34 Weeks

Hello: During the 32-week prenatal check-up, the baby's biparietal diameter (BPD) was consistent with the gestational age, but the abdominal circumference (AC) was 2 weeks smaller, and the estimated fetal weight (EFW) was 1 week smaller. Now at 34 weeks, the baby's BPD ...

Dr. Lü Lizheng reply Obstetrics and Gynecology
The response may indicate a measurement error; it is advisable to discuss this with a physician and repeat the measurement. If the results still show a lower value, it could suggest growth delay, and it is important to discuss potential causes with the physician and arrange appro...

Understanding Fetal Growth Discrepancies: What to Expect During Pregnancy

Dear Doctor: I am currently 26 weeks pregnant. During my last ultrasound, which was around 27 weeks, the baby weighed approximately 1080 grams. After a week, I went to another hospital for a check-up, and the baby was estimated to be around 29 weeks and weighed 1450 grams. Why di...

Dr. Liu Yuhong reply Obstetrics and Gynecology
Measuring fetal weight via ultrasound within a short time frame (less than 2 weeks) will inevitably result in discrepancies! Different examiners, the gestational age at the time of the examination, varying ultrasound machines, as well as the fetal position and amniotic fluid volu...

Understanding Fetal Head Size: Concerns and Diagnostic Options

Hello, I am currently 33 weeks pregnant. Since week 26, ultrasounds during my prenatal check-ups have shown that the fetal head is measuring 2 to 3 weeks ahead. During today's check-up, the doctor provided the following measurements: fetal head at 40 weeks, abdominal circumf...

Dr. Lü Lizheng reply Obstetrics and Gynecology
1. Ultrasound can clearly determine whether there is hydrocephalus. If there is a medical center nearby, you can directly undergo a "high-level ultrasound" examination. You are also welcome to come to our hospital, where I can perform this examination for you. 2. Besi...