Do hCG levels rise with blighted ovum? Yes, most of the time hCG levels will rise, giving you a positive pregnancy test and symptoms of pregnancy. This is because the placenta continues to give off hCG even if an embryo is not present.
Symptoms of blighted ovum
When the fertilized egg fails to develop into an embryo, hCG levels begin to drop and pregnancy symptoms will begin to disappear. At this point it's possible to experience signs of miscarriage, like bleeding and cramping.
The anembryonic pregnancy may manifest as an empty amnion sign where the expanded amniotic sac does not contain an embryo (Figure 21-13). A yolk sac should be visible when the hCG exceeds 7200 mIU/mL, and an embryo with cardiac activity should be detected at an hCG of 10,000 mIU/mL.
If the hCG level is high and no gestational sac is seen in the uterus, this makes it highly likely that there is an ectopic pregnancy. Checking the hCG level and then checking it again in 48 hours tells you how fast the hCG level is rising.
Because a blighted ovum still makes pregnancy hormones, it may still show up as a positive pregnancy test. A blighted ovum will eventually cause a miscarriage, usually at 7 to 12 weeks of pregnancy. Your body realises that the pregnancy is not developing properly and starts to shed blood and tissue from the uterus.
From what is known, experts believe blighted ovum accounts for a third of miscarriages that occur before 8 weeks gestation. Even though the embryo is not developing properly or has stopped altogether, a woman may experience early pregnancy symptoms since the body has recognized something attached to the uterus.
No yolk sac at 5 to 6 weeks of gestation may mean either that the pregnancy is less than 6 weeks along or there has been a miscarriage. Having another ultrasound in 1 to 2 weeks can determine if the pregnancy is viable or not.
A blighted ovum, also called an anembryonic pregnancy, occurs when an early embryo never develops or stops developing, is resorbed and leaves an empty gestational sac. The reason this occurs is often unknown, but it may be due to chromosomal abnormalities in the fertilized egg.
It's possible for a blighted ovum to be misdiagnosed if the dating is off with your pregnancy, Schaffir says—meaning, you think you're six or seven weeks along but you're actually five or less weeks into your pregnancy.
Not Seeing Gestational Sac on Ultrasound
If it has been five weeks since your last menstrual period but your hCG level has not been measured, there is a possibility that seeing no gestational sac simply means that you ovulated late and your pregnancy has not yet reached 5 weeks gestational age.
Alternatively, an anembryonic pregnancy can be established when there is no embryo on a follow-up endovaginal scan: ≥11 days after a scan demonstrating a gestational sac with a yolk sac, but an absent embryo. ≥ 2 weeks (14 days) after a scan demonstrating a gestational sac without an embryo or a yolk sac.
It contains a yolk sac (protruding from its lower part) but no embryo, even after scanning across all planes of the gestational sac, thus being diagnostic of an anembryonic gestation. A blighted ovum or anembryonic gestation is characterized by a normal-appearing gestational sac, but the absence of an embryo.
Because of the nature of anembryonic pregnancy, symptoms of a blighted ovum can include both early pregnancy symptoms (such as a missed period, positive pregnancy test, breast tenderness, and even morning sickness) and symptoms of early miscarriage (such as abdominal cramping and vaginal bleeding).
Yolk sac and gestational sac
if not seen, when G.S. is more than 20 mm. it means it is a case of blighted ovum.
With a blighted ovum, hCG can continue to rise because the placenta may grow for a brief time, even when an embryo is not present. For this reason, an ultrasound test is usually needed to diagnose a blighted ovum -- to confirm that the pregnancy sac is empty.
Pregnancy tests work by detecting the presence of hCG. After a miscarriage, hCG levels begin to drop, but they don't decrease to zero immediately. So, if you take a pregnancy test immediately after experiencing a miscarriage, it will almost certainly still be positive.
But that's confusing: a blighted ovum exists before any bleeding happens. It's often spotted late, or not at all. So a blighted ovum is sometimes called a silent miscarriage. One in two early miscarriages are due to a blighted ovum – it's that common.
Unfortunately, you can have a positive pregnancy test but not see a baby on the ultrasound. The gestational sac encloses the developing baby and contains amniotic fluid. If it's not visible by around 5 weeks gestation, it may mean that the pregnancy is not viable or a miscarriage has already happened.
At 6 weeks
During the bleeding, you may see clots with a small sac filled with fluid. The embryo, which is about the size of the fingernail on your little finger, and a placenta might be seen inside the sac. You might also notice something that looks like an umbilical cord.
With a quantitative hCG level that high, you would expect to see a yolk sac already. Because the mean gestation sac measures >14 mm, and there is no visible yolk sac on the scan, it is likely that your patient has an anembryonic gestation or blighted ovum at this time.
If your healthcare provider can't see the yolk sac, it might indicate the pregnancy is not viable. That means the pregnancy won't result in a birth. But it also can mean that the estimated gestational age is wrong. Your healthcare provider may recommend another ultrasound in a week or two to look again.