1 in 6 pregnancies miscarry, usually in the first trimester, this can be incredibly stressful and upsetting for patients and their families, especially if it is repeated. If the pregnancy is lost at a later stage, i.e. >24weeks gestation/foetus weighed >500g and showed signs of life at birth it is registered as a live birth where the baby died.
Types of Miscarriage
- Missed miscarriage – the cervix is closed, the foetus has died but has not been expelled from the uterus. On USS a pregnancy sac without any fetal heart activity.
- Incomplete miscarriage – the cervix is open, the foetus has died but is only partially expelled from the uterus some products of conception remain within the uterus
- Complete miscarriage – the cervix is closed, the foetus has died and has been expelled from the uterus and the cervix has closed again behind it
- Threatened miscarriage – the cervix is closed and foetal heart activity js detected but there is PV bleeding (bleeding through the vagina) in the first 20 weeks of pregnancy
You can still have a positive pregnancy test after a spontaneous miscarriage as beta HCG levels take a while to drop. Therefore repeat beta HCG levels are recommended.
Most of the time we do not know why a pregnancy miscarries, around 25% are caused by chromosomal abnormality.
If the retained products of conception are <30mm and the woman is not bleeding then they can be left otherwise they have to be removed, either medically or surgically:
- Prostaglandins (misoprostol) – given as a pessary and an oral tablet to soften the cervix and trigger uterine contractions
- Anti progesterone (mifepristone) – given orally 48hrs before the prostaglandin to stop the body supporting the pregnancy and prepares the cervix
- ERPC (evacuation of retained products of conception)
After miscarriage or termination it is important to check the mother’s rhesus status and, if she is negative, give Anti D.