According to data released by the Society for Assisted Reproductive Technology, more than 72,000 babies were born in 2017 as a result of IVF or other forms of ART. While fertility clinicians are experts in the technology and procedures that help patients build their families, not all of them are prepared to confirm a healthy pregnancy once a patient achieves one. Show To confirm a clinical pregnancy following ART, reproductive endocrinologists must perform two evaluations: a blood test and a pregnancy confirmation exam using transvaginal ultrasound. Blood Testing and Ultrasound: Two Key Steps for Pregnancy Confirmation While fertility clinics vary in practice, most start by testing a patient's blood two or more times for human chorionic gonadotropin (hCG) approximately nine to 12 days after an embryo transfer, or 14 to 17 days after an insemination. The hCG number should double every 48 to 72 hours, according to Patient Management in Obstetrics and Gynecology. Although growth may be detectable earlier, some type of development should be seen on transvaginal ultrasound when hCG levels reach 2,000 mIU/ml, notes the American Pregnancy Association. For transabdominal ultrasound, the threshold is 3,600 mlU/ml. 3D Ultrasound Image at 6 Weeks showing Yolk Sac Starting at around ten weeks gestation, physicians perform between one and three transvaginal ultrasounds before referring the patient to an obstetrician. The first ultrasound is the initial attempt at a pregnancy confirmation exam, during which a clinician aims to verify an intrauterine pregnancy and possibly identify whether the patient has multiple gestations. Subsequent ultrasounds measure early cardiac activity and viability. Expected Visualization and Measurements Practice guidelines from the International Society of Ultrasound in Obstetrics and Gynecology (ISUOG) dictate that during the first transvaginal ultrasound, physicians should expect to see the following:
Step-By-Step Pregnancy Confirmation Exam Guide Step one: Evaluate the uterus, adnexa and cervix for the gestational sac. If the gestational sac is seen, document the location. Even without cardiac activity, if the gestational sac is visualized in the uterus, it is considered an intrauterine pregnancy. Examine the gestational sac for the absence or presence of a yolk sac and fetal pole. If possible, measure and record the crown-rump length (CRL), as this is the most accurate indicator of gestational age. If it is very early in the pregnancy, instead of a yolk sac and fetal pole, eccentric intrauterine fluid collection with an echogenic rim will be visible. If there are no signs of an ectopic pregnancy, the fluid likely indicates an intrauterine pregnancy. However, follow up with hCG levels and a repeat transvaginal ultrasound to confirm. Step two: Determine the absence or presence of cardiac activity. Record any cardiac activity with a two-dimensional video clip or M-mode imaging, rather than pulsed Doppler ultrasound, to limit the rise in soft tissue thermal index. Typically, cardiac motion can be observed once the fetal pole is at least 2 mm. If the fetal pole is less than 7 mm but no cardiac activity is visible, repeat the transvaginal ultrasound in one week. Step three: Document the number of gestations. Chorionicity and amnionicity should be noted in the case of multiple gestations. Step four: Evaluate the uterus, adnexa, cervix and cul-de-sac for abnormalities. Image and document all abnormalities. Specifically, look for the presence, location, appearance, size and number of adnexal masses, leiomyomas, fluid and other uterine abnormalities. When the Scan Is Abnormal If the visualization or measurements are not as expected, it does not necessarily mean the pregnancy is nonviable. Some factors may lead to an incorrect diagnosis, such as:
Radiopaedia reports that if the gestational sac measures 8 mm with no visible yolk sac, or the gestational sac is larger than 16 to 24 mm but there is no fetal pole, then pregnancy failure is a distinct possibility. International Differences ISUOG recommends ultrasounds during the second trimester, but asserts that routine scanning during the first trimester (aside from an initial scan at 11 to 13 weeks) is unnecessary in the absence of a potential problem, especially before 10 weeks. This goes against some physicians' operational norms in North America, where some patients expect an ultrasound as early as six weeks gestation. Meanwhile, the World Health Organization is trying to expand resources and training on offering a pregnancy confirmation exam to providers in poor and rural areas, who face more political, logistical and infrastructural challenges. International standards for correlating fetal CRL to gestational age do not exist. Addressing Patient Fears Especially in recent years, perhaps thanks to social media and pregnancy blogs, some pregnant patients fear that ultrasounds may harm their baby. However, according to the American College of Obstetricians and Gynecologists, "There is no evidence that ultrasound is harmful to a developing fetus." Although patients cannot and should not be forced to undergo an ultrasound, providers should explain that a transvaginal ultrasound uses high frequency sound waves instead of radiation, making it safer than X-rays. Ultrasounds have been performed safely for decades, and are critical for identifying abnormalities that may lead to poor maternal or fetal outcomes. Learning how to reliably confirm a pregnancy and ease patient concerns are crucial skills for any fertility clinician. Keeping abreast of international guidelines can help physicians address any gaps in their knowledge.
A fetal pole is an embryo, one of the first stages of pregnancy. In a healthy pregnancy, the fetal pole develops into a fetus. An early prenatal ultrasound can view and measure the fetal pole. This provides information about the embryo’s location, gestational age, possible complications and whether there’s more than one embryo.
A fetal pole is one of the first stages of an embryo’s development in pregnancy. During a healthy pregnancy, the fetal pole develops into a fetus, then an infant. It’s also called an embryo or embryonic pole. Is a fetal pole a baby?Medically speaking, a fetal pole isn’t yet a baby. It’s an embryo until about the 10th week of gestation. It then becomes a fetus and goes through fetal development until birth.
Healthcare providers can see and measure a fetal pole using prenatal ultrasound. The images can provide important information to healthcare providers early in pregnancy, such as:
A fetal pole is located next to a small pouch called the yolk sac. That’s where it gets its nutrients. The fetal pole and yolk sac are contained inside the gestational sac. In a normal pregnancy, the gestational sac is in your uterus. What does a fetal pole look like?A fetal pole is curved. At one end is the head of the embryo, called the crown. At the other end, there’s a tail-like structure, called the rump. How big is an embryo?A fetal pole’s size depends on how far along the pregnancy is. An embryo is measured from the crown to rump (crown-to-rump length, or CRL). When an embryo is first detected, it may be only 1 or 2 millimeters. It grows to about 30 millimeters by the 10th week of pregnancy. When does the fetal pole appear?A fetal pole is often visible with vaginal ultrasound at about five and a half weeks of pregnancy. But sometimes it’s not seen for several weeks, depending on the type of ultrasound and the angle of your uterus. What comes first, fetal pole or heartbeat?A heartbeat often is visible around six weeks of gestation, or soon after your provider sees the fetal pole.
If ultrasound cannot locate the fetal pole when expected, you may need a repeat test in a few days. An absent fetal pole can mean several things, including:
If a fetal pole is found anywhere other than your uterus, it’s considered an ectopic pregnancy. The condition is a medical emergency and not a viable pregnancy. Other places a gestational sac may be found include:
What if I have a fetal pole with no heartbeat?If a fetal pole measures more than 7 millimeters and your provider doesn’t see a heartbeat, this is an abnormal pregnancy and will result in a miscarriage. Your healthcare provider will help you understand your situation. They may order other tests to learn more.
Many problems that occur with the fetal pole cannot be prevented. For example, there’s no way to change the location of an ectopic pregnancy or to prevent genetic problems that can lead to miscarriage after you’re pregnant. But several strategies can help you and your embryo be as healthy as possible:
A note from Cleveland Clinic A fetal pole is an embryo, one of the first stages of pregnancy. During a healthy pregnancy, a fetal pole develops into a fetus, then a baby at birth. Talk to your healthcare provider about the results of your prenatal ultrasound and what they mean for your pregnancy.
Last reviewed by a Cleveland Clinic medical professional on 03/21/2022. References
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