Normal range of S/D value at 33 weeks of pregnancy
Sep 13, 2022
Source: Cainiu Health
Dr. Chen Zhe
Introduction
The umbilical artery S/D ratio can reflect hemodynamic changes in placental blood flow and help assess placental function. At 33 weeks of gestation, the normal S/D ratio should be less than 3; a value greater than 3 suggests fetal intrauterine hypoxia. The S/D ratio is generally first measured around 20 weeks of gestation, when it is close to 5, and gradually decreases as gestational age increases, falling below 3 after 30 weeks of gestation.
First-time mothers who are pregnant often want to know about their baby's health and need to confirm whether the S/D value at 33 weeks of gestation falls within the normal range. So, what is the normal S/D value range at 33 weeks of pregnancy?
Normal S/D Value Range at 33 Weeks of Pregnancy
The umbilical artery S/D ratio reflects hemodynamic changes in placental blood flow and helps assess placental function. At 33 weeks of gestation, the S/D ratio should normally be less than 3. A value greater than 3 may indicate fetal hypoxia in utero. The S/D ratio is typically first measured around week 20 of pregnancy, when it is close to 5, and gradually decreases as gestational age increases, dropping below 3 after week 30. If the S/D ratio remains above 3 at 33 weeks, this suggests reduced placental or umbilical cord function, which, if not improved over time, could lead to intrauterine fetal hypoxia. In such cases, pregnant women can try lying on their left side and receiving oxygen therapy, while also undergoing fetal heart rate monitoring and ultrasound examinations to dynamically observe the fetus’s growth and condition in utero.
If an abnormal S/D value occurs only once, the expectant mother can have a follow-up test after 3–7 days, during which she should closely monitor fetal movements. If abnormalities persist, prompt medical consultation is recommended to check for possible issues such as umbilical cord compression or placental dysfunction. If subsequent tests show a normalized S/D ratio and fetal heart monitoring reveals no abnormalities, routine prenatal checkups are sufficient. It's important to rest adequately and maintain a relaxed state of mind.
During pregnancy, it is advisable to avoid spicy, strongly flavored, or irritating foods, and instead consume more fresh fruits and vegetables. Maintain a regular work-rest schedule, avoid excessive fatigue, stay calm, focus on healthy fetal development, and attend all scheduled prenatal appointments. We hope this information has been helpful. Wishing you good health and happiness!
