Risk Factors for pre-eclampsia and fetal growth restriction

Why am I being offered aspirin?

During pregnancy and the postnatal (after birth) period, some women and birthing people have an increased chance of developing pre-eclampsia or fetal growth restriction (see explanation of these conditions below).

Midwives assess all pregnant women and birthing people at booking regarding their chances of developing pre-eclampsia, or fetal growth restriction. Often, these conditions co-exist and risk factors overlap.

Those with risk factors who may be more likely to develop these conditions will be advised to take 150mg of aspirin in the evening by mouth after food, if possible, from 12-16 weeks of pregnancy until 36-weeks of pregnancy.

There are studies that show that this can help lower the chances of developing pre-eclampsia and fetal growth restriction.

Aspirin belongs to a group of medicines called antiplatelet drugs. These medicines stop the platelets in your blood sticking together so you are less likely to get blood clots.

Your midwife or obstetrician will advise you how you can obtain aspirin 150mg.

What is pre-eclampsia?

Pre-eclampsia is a complication that occurs in 5 to 8 in every 100 pregnancies.

It involves a rise in blood pressure which is accompanied by a leakage of protein from the kidneys into your urine. This protein can be found by testing your urine at each visit before giving birth.

In severe cases it can cause:

headaches
visual disturbances
stomach pain
facial swelling
nausea

These symptoms can slow the growth of your baby leading to fetal growth restriction, see below.

Am I at risk for developing pre-eclampsia?

Pre-eclampsia can occur in any pregnancy, but you are at higher risk if:

your blood pressure was already high before you became pregnant
your blood pressure was high in a previous pregnancy
you have a medical disorder such as diabetes or a kidney condition
you have a condition that affects the immune system such as lupus

The importance of other risk factors is less known but generally are more likely to develop pre-eclampsia if you have 2 of the following:

aged 40 or over
this is your first pregnancy
it is more than 10 years since your last pregnancy
your BMI is 35 or more when you first see your midwife
you have a family history of pre eclampsia
if you are expecting twins or triplets.

What is fetal growth restriction?

Babies who are small for gestational age (SGA) may be naturally small and healthy or may be smaller because they are growth restricted (FGR feta growth restriction).

In general smaller babies may not have the energy reserves to cope with additional stress, such as labour, and also have a slightly higher chance of stillbirth later in pregnancy.

Am I at risk of developing fetal growth restriction?

Fetal growth restriction is more likely if you have had a previously small or growth restricted baby, or any of the below risk factors:

you were smoking in pregnancy or taking recreational drugs
are aged over 40 years
have a medical disorder such as diabetes, a kidney condition, or if you have a condition that affects the immune system such as lupus
previously had a pregnancy affected by high blood pressure or pre-eclampsia
have had a previous preterm birth or second trimester miscarriage in which problems with your placenta were involved
had a previous stillbirth with a normal weight baby for the gestation
have a low PAPP-A level (blood test checked during the early combined screening test). The screening team will contact you about this if it is found to be low.
have had gastric bypass surgery in the past
have significant recurrent bleeds in this pregnancy
have a single umbilical artery in your placent
have adult congenital heart disease (ACHD) as for example Post Fontan.

Will I need any other tests for pre-eclampsia or fetal growth restriction?

If you have any of these risk factors, you will be referred to the obstetric antenatal clinic for planning the pregnancy.

You may be offered an extra scan performed at the time of the anomaly (20-weeks) scan to check the uterine artery Dopplers (UADs). This assesses the flow of blood in the vessels which supply the uterus (womb) and can provide an indication as to whether the baby will grow to its full potential or raise the possibility of developing pre-eclampsia.

Very rarely the sonographer may not be able to obtain your UAD’s due to technically difficulties. According to the results, your consultant will discuss the on-going care plan for you including extra growth scans in the third trimester. You will also be offered regular scans two to four weekly after 28 weeks or 32 weeks depending on your risk. Your obstetrician and midwife will discuss this with you.