What are recurrent miscarriages?
Recurrent or repeated miscarriages are when a woman has miscarried on three or more consecutive pregnancies.
Miscarriage (also referred to as pregnancy loss) can be devastating if it happens once; sadly some individuals miscarry on multiple occasions, and if three or more consecutive pregnancies are lost a diagnosis of recurrent miscarriage can be made. At this point, further tests are often conducted to find what is causing the pregnancies to be lost.
Causes of recurrent miscarriage
There are several factors that can lead to repeated miscarriages:
- Genetic factors – in a small number of cases, one partner may be repeatedly passing on an abnormal chromosome that is causing the miscarriages.
- Hormonal – conditions like polycystic ovarian syndrome or imbalances in pregnancy hormones can be risk factors for miscarriage.
- Uterine problems – an abnormally-shaped womb, such as in a patient with bicornuate uterus increases the risk of miscarriage.
- Cervical weakness – if this is detected early, stitches or cervical cerclage may be recommended to reinforce the cervix.
- Blood clotting disorders – rare disorders like systemic lupus erythematosus and antiphospholipid syndrome affect the blood flow to the placenta. Clots may form, which can affect the function of the placenta and potentially starve the foetus of oxygen and essential nutrients, leading to miscarriage.
- Age – the older the parents, the lower the chance of carrying a baby to term.
Can miscarriages be prevented?
Most pregnancies are monitored to an extent, with most UK hospitals offering at least two ultrasound scans during a pregnancy, as well as regular prenatal check-ups. These measures often pick up irregularities in the pregnancy; however, if a woman suffers several miscarriages, a closer examination may be needed.
After recurrent miscarriages, certain tests and scans are usually offered to try to identify the problem. These tests include:
- Karyotyping – testing for chromosome abnormalities. This may involve testing the DNA of the foetus and both parents. If genetics are found to be responsible, a clinical geneticist will be able to go over options with the patients and explain if there are any fertility treatments, such as IVF, that could help.
- Ultrasound scans – these scans can detect abnormalities in the structure of the womb or weakness in the muscles of the cervix.
- Blood tests
If a cause is discovered, the doctors and patient can work to counter it to try to prevent further miscarriages. For instance, some blood clotting disorders can be treated with medication, while a weakened cervix can be strengthened with a small stitch of strong thread (cervical cerclage) carried out once the patient is pregnant again.
Measures such as maintaining a healthy weight and avoiding harmful substances including alcohol and tobacco also lower the risk of miscarriage.