What Causes Pre-Eclampsia?
It isn't really known what causes the disease. Many changes have been discovered in hormone levels which explain some of the findings, but the actual trigger isn't known. It has a lot to do with the placenta (afterbirth).
The placenta is not as well developed as it should be, with thinning of the blood vessels from mum's side that invade the placenta as it grows. These changes begin as early as 18-20 weeks, even in the (usual) women who don't develop pre-eclampsia until toward the end of pregnancy.
There are also blood clots blocking off the arteries in the placenta, reducing the amount of blood getting across to the baby. This explains the common finding of a smaller than expected baby in women who have pre-eclampsia.
There is lots of research going on at the moment to try and discover why it happens and how we might go about preventing it.
What Makes Pre-Eclampsia More Likely?
The following can predispose you to developing pre-eclampsia, but many cases occur without any risk factors at all.
- If it is your first pregnancy
- Pre-eclampsia in a previous pregnancy
- Age under 20years or over 35years
- Short stature
- If you suffer from migraines
- Family history of pre-eclampsia or eclampsia
- Previous hypertension
- If you have Raynaud's disease
- If you are underweight
- If you have systemic lupus erythematosis (SLE)
- Multiple pregnancy (eg. twins)
- Hydatidiform mole
What Kind of Symptoms Does it Cause?
Usually high blood pressure doesn't cause any symptoms, but the complaints below are common if pre-eclampsia is present:
- Flashing lights, stripes before the eyes, floaters or black-outs of vision
- Light hurting the eyes (photophobia)
- Pain at the top of the abdomen, or on the right side under the ribs
- Just not feeling right.