A blighted ovum, also known as an empty sac, is one of the most common causes of pregnancy loss during the first trimester. It is a situation that often causes significant emotional distress: the pregnancy test is positive, typical pregnancy symptoms may appear, and yet an ultrasound scan reveals that the gestational sac is empty. Although the diagnosis can be difficult to come to terms with, it is important to know that it is usually due to spontaneous biological causes and, in most cases, does not affect future pregnancies.
What is an anembryonic pregnancy?
An anembryonic pregnancy occurs when the gestational sac implants in the uterus and begins to grow, but the embryo fails to develop or stops developing at a very early stage. Because it is the gestational sac that produces hCG, the test is positive and typical signs of pregnancy such as nausea or tiredness may persist. In the vast majority of cases, anembryonic pregnancy is due to genetic or chromosomal abnormalities that occur randomly during fertilisation.
How is the diagnosis confirmed?
The diagnosis is usually made by ultrasound, generally between week 6 and 8 of gestation, when the following is observed:
- The gestational sac with no visible embryo.
- Absence of the expected embryonic development.
In some cases, it may be necessary to repeat the ultrasound scan a few days later to confirm the diagnosis with certainty.
What is the treatment?
Once confirmed, there are various options depending on the clinical situation and the patient’s preference:
- Watchful waiting: the body is allowed to recognise the situation and expel the tissue naturally.
- Medical treatment: medication is used to facilitate the process.
- Uterine aspiration or curettage: this is a medical procedure to empty the uterine cavity in a controlled manner.
At every stage, emotional support is essential to help manage the grief.
Can it affect future pregnancies?
Having an anembryonic pregnancy does not mean you have a fertility problem, nor does it, in itself, increase the risk of it happening again. In fact, most women who go through this experience go on to have a healthy, full-term pregnancy.
However, in cases of recurrent miscarriages, it may be advisable to carry out a more comprehensive investigation to look for possible causes.
