Early pregnancy failure is a common cause of miscarriage. This is also known as a blighted ovum or anembryonic gestation. It happens when a fertilised egg implants in the uterus but never develops into an embryo. Cells develop to form the pregnancy sac, but not the embryo itself. This condition occurs within the first trimester and in most cases even before a woman knows she is pregnant. Miscarriage, in this case, happens due to a high level of chromosome abnormalities.
The early signs of pregnancy such as a missed or late menstrual period and even a positive pregnancy test are all seen in this condition also. Due to the regularly rising hCG levels, pregnant women assume that their pregnancies are just normal.
This happens because the placenta will continue to grow and support itself even without a baby for a short time and pregnancy hormones also continue to rise. Things become clear only when an ultrasound test shows either an empty womb or an empty gestational sac.
The leading cause of blighted ovum is considered to be abnormal chromosomes in a study done in 2007. The researchers analysed the genetic material from nearly a hundred blighted ovum and found that more than two-thirds of them had abnormal chromosomes. In many cases, the eggs or embryos had an extra chromosome or were missing a chromosome. Since these eggs that were fertilised didn’t have the right genetic material to grow into an embryo they couldn’t continue to develop. In other cases, genetic mutations, rather than whole chromosome duplication or deletions, are probably responsible for anembryonic pregnancies.
A blighted ovum feels similar to a normal pregnancy, even after the fertilised egg has stopped growing. That’s because the fertilised egg has implanted itself into the uterus and so the body considers it to a growing embryo, and so it produces hormones that cause early pregnancy symptoms.
Because this condition occurs so early in the pregnancy and so not all cases are diagnosed. This makes it difficult for researchers to come up with an exact measure of how often blighted ovum occurs. But approximately 20 percent of all pregnancies end in miscarriage, and 80 percent of those happen in the first 12 weeks. Experts estimate that a third of even previous miscarriages those before eight weeks gestation are due to blighted ovum.
A blighted ovum can only be diagnosed with an ultrasound. This is because only an inside peek at your uterus can reveal that a fertilised egg hasn’t developed into an embryo and the other pregnancy signs continue to happen as usual.
As many of these cases happen even without the knowledge of the women that they have become pregnant, there is no treatment required. The body recognises after sometime that an embryo isn’t developing and only an implantation has happened. It will expel the contents of the uterus including the undeveloped fertilised egg. This will come out along with bleeding similar to a heavy period. In most cases of a blighted ovum, women only think that their period had come out a few days late.
When a blighted ovum is diagnosed with an ultrasound and your body fails to recognise it, the doctor will often recommend waiting a few days or weeks before taking any action. This is to allow the body to recognise the condition and expel the anembryonic pregnancy naturally. The hormones that an implanted embryo triggers to produce also cause the uterus to keep that embryo intact, even if it’s not developing. So, after a particular period, doctors would recommend either a pill called misoprostol, which helps trigger the uterus to clear the contents, or a dilation and curettage (D&C), a brief surgical procedure that helps empty the uterus.
The single occurrence of blighted ovum won’t affect the odds of getting pregnant again. In one 2009 research of women with early miscarriages, which included blighted ovum, around 80 percent went on give birth to a healthy baby within five years.
It is generally recommended to wait for one or two periods to conceive. The first period after a blighted ovum happens four to six weeks after you miscarry or have the tissue removed. One Scottish study of over 30,000 women concluded that women who get pregnant within six months of having a miscarriage actually have the best odds of having a healthy pregnancy. Those women had fewer miscarriages or ectopic pregnancies than women who got pregnant six to 12 months after their miscarriage.
One incident of miscarriage, may it be due to blighted ovum or any other causes doesn’t indicate that there is a problem with you (unless diagnosed otherwise after the miscarriage). This does not tamper your chances of getting pregnant again in almost all cases of a blighted ovum. Doctors usually wait until a woman has had two or more consecutive miscarriages to order special blood and genetic tests to try to find out what’s going wrong.