Antenatal care for women at risk of preterm birth

Overall, most women (more than 90 per cent) give birth to their baby after 37 weeks of pregnancy, called term delivery.

Approximately 10 per cent of women give birth to their baby before 37 weeks of pregnancy, and this is called preterm. Most babies born preterm do well, but a few have long term problems.

At the Royal Free London, we offer women who have risk factors that increase the chance of preterm birth the option of being seen in a specialist antenatal service.

Preterm birth clinic

The preterm birth clinic is for women who have an increased risk of delivering their baby preterm because:

• They have had a previous preterm birth or a late miscarriage.
• Their womb is an unusual shape e.g., unicornuate.
• Their cervix has been found to be shorter than normal by ultrasound scan (<25mm).
• They have had a stitch (cervical cerclage) placed in their cervix in a previous pregnancy or in this pregnancy. • They have had surgery on their cervix (neck of the womb). • Cone biopsy.
• LLETZ (large loop excision of the transformation zone).

The aim of the clinic is to support women by monitoring them closely in the first two-thirds of pregnancy and acting appropriately to try to prevent a preterm birth. Once the pregnancy reaches 26-28 weeks most women can be looked after by their midwife, general obstetrician, and GP. The preterm birth clinic is held at Royal Free and Barnet hospitals.

Royal Free hospital

Every Tuesday afternoon in the early pregnancy and gynaecology assessment unit (EPAGU) on the fifth floor of the Royal Free hospital.

• Dr Henna Mohiudin, consultant obstetrician and gynaecologist.
• Sherry Boostanipour, preterm birth midwife.

Barnet hospital

Alternate Thursday afternoons, first floor maternity wing:

• Mr Grigoris Premetis, consultant obstetrician and gynaecologist.
• Isa Essilfie-Quaye, antenatal clinic matron.

We are a teaching hospital. Junior doctors and student doctors and midwives will also be in the clinic to observe and to learn. Please let us know if you would prefer they leave the room during your appointment.

Because of the nature of the clinic, we often need to see women urgently and frequently, which makes our clinics very busy. We aim to see you on time, but we will inform you if we are running late. Please ask a member of staff at the reception if there are any delays to your appointment. We hope that your visit to our clinic meets your expectations. We will invite you to complete a patient satisfaction questionnaire.

First visit

On your first visit you will initially be seen by the clinic midwife and doctors. Your appointment may take up to an hour so please allow this amount of time. A detailed history will be taken. You will then be offered swabs (taken from the vagina and cervix using a speculum examination) to check for the following infections:

• Chlamydia.
• Gonorrhoea.
• Trichomomas.
• Group B streptococcus.

These infections are not common, but women who have them have a higher risk of preterm birth. Treatment can reduce the risk. If infection is found, we will discuss the need of any treatment with you.

Every visit thereafter

At each of your visits to the clinic, we’ll carry out several tests to monitor your health during your pregnancy. This will include:

1. Testing your urine for signs of a urine infection at each visit. This is because urinary tract infections can trigger preterm labour. If infection is found, we will arrange treatment with the appropriate antibiotics.
2. Monitoring your blood pressure at each visit. Raised blood pressure in pregnancy can increase the risk of preterm birth.
3. Measuring the length of your cervix at each visit. To get a clear view of the cervix we will perform a scan through the vagina (trans-vaginal scan). This is performed by inserting a specially designed ultrasound transducer into the vagina. This does not harm the baby and will not cause bleeding or miscarriage. The length of the cervix can give a guide as to the chance of you delivering your baby preterm.

Sometimes the top portion of the cervix (internal os) opens up, but the bottom part (external os) remains closed. This is termed “funnelling” and is associated with a higher chance of delivering preterm.

If your cervix is short or if there is funnelling, we will discuss with you the best management. This may include closer monitoring or admission to hospital. We may also recommend a course of steroids, progesterone treatment or cervical cerclage. For further information please see below.

Fetal fibronectin test

The fetal fibronectin test can be another useful way to predict the chance of you delivering your baby preterm. The test is most accurate if done between 22 and 35 weeks of pregnancy, but an earlier test can be useful. A swab is taken of the vaginal secretions using a speculum examination and a result is available within 10 minutes. The test does not harm your cervix.

By combining the result of the fibronectin test with the length of the cervix on scan we can make an individual plan of care for you using an algorithm that was developed from a research study carried out by King’s College London, and Guy’s and St Thomas’ NHS Foundation Trust.

A fetal fibronectin test is not indicated if the cervical scan findings are normal. The test may give a falsely high reading if you have had sexual intercourse or heavy vaginal bleeding within the last 24 hours. Please tell the doctor or midwife about this before you have the test.

Maternal steroids

When babies are born very preterm, their lungs are ‘stiff’ and the baby needs to make a big effort to open up the airways to breathe. A course of steroids (two injections over 24 hours) given to the mother can help the baby inflate their lungs and breathe better if they are born early. We may recommend giving you a course of steroids if there appears to be a high chance of you delivering your baby preterm.

Cervical cerclage

Cervical cerclage is a minor surgical procedure performed by an obstetrician that aims to keep your cervix closed by placing a stitch into your cervix. This is done under anaesthetic. The cervix is reached through the vagina using a speculum. Having a cervical cerclage put in place may mean that the neck of your womb is less likely to undergo changes that can cause it to open.

Your baby is therefore held safely inside the womb and your chances of getting an infection or going into labour too early are also reduced. There are some risks to the procedure and not all women benefit. We will discuss with you whether cervical cerclage may benefit your pregnancy.

An elective cervical cerclage may be recommended if you have delivered your baby preterm in previous pregnancies or if you have had surgery or trauma to your cervix that shortens or weakens it. In this case the cervical cerclage is usually placed after your dating scan at 11-13 weeks of pregnancy.

Ultrasound-indicated cervical cerclage: In some cases, small changes to your cervix such as shortening or funnelling can be detected on ultrasound scans you have when attending the hospital to monitor your pregnancy. In this case we may arrange for you to have a cervical cerclage as soon as possible to try to prevent any further changes.

Common questions

Will continuing to work increase the chance of delivering my baby preterm?

There is no evidence that continuing work will increase your risk of preterm birth. It may be appropriate to consider some time off work if your occupation involves standing for long periods or long distance travelling. Some women feel a short period away from work reduces their stress levels, particularly if they have previously had a preterm birth or late miscarriage. We can supply a letter for your employer if it is felt advisable that you take some time off work.

Can I exercise in my pregnancy?

There is no risk associated with starting or continuing moderate exercise during pregnancy. Any sport that may cause abdominal trauma, falls or excessive joint stress should be avoided.

Can I have sex during my pregnancy?

There is no evidence that intercourse causes preterm birth. However, we would advise you to refrain from intercourse if:

1. Your placenta is low-lying. Once the placenta has moved away later in pregnancy it may be safe to resume sexual intercourse. You should await advice from your obstetrician.
2. You have vaginal bleeding.
3. You have had a cervical cerclage placed. You should avoid intercourse until you have been seen again in the preterm birth clinic.

Can I do anything to prevent me from delivering my baby early?

Women who smoke have a higher chance of delivering their baby preterm (about two times higher risk) and we advise smokers to stop smoking immediately. Getting professional help increases the chance that you will stop smoking. Your GP can provide support, can prescribe nicotine patches and can refer you to stopping smoking services. There are benefits even if you stop smoking in the middle of pregnancy.

Douching the vagina (rinsing of the vagina) interferes with both the vagina's normal self-cleaning and with the natural bacterial culture of the vagina. It has been found to increase the risk of bacterial vaginosis and may increase the chance of preterm birth. We advise all women not to douche their vagina.

Some diets are associated with a lower risk of preterm birth. Eating a diet rich in vegetables, fruits, oily fish, water as beverage, whole grain cereals and fibre rich bread is beneficial. Increasing the intake of omega-3 long-chain polyunsaturated fatty acids in a fish oil supplement has been linked to a lower risk of preterm birth.

Should I be concerned by any symptoms?

You should speak to a midwife if you experience any of the following symptoms:

1. Increasing watery discharge.
2. Increasing abdominal pain.
3. Vaginal bleeding.
4. Increasing feeling of pressure on your vagina.

References

• Bolt LA et al, Chandiramani M, De Greeff A, Seed P, Shennan AH. BJOG-an International Journal of Obstetrics and Gynaecology. 2010;117(5):624.
• Shennan A, Jones G, Hawken J, Crawshaw S, Judah J, Senior V, et al. BJOG-an International Journal of Obstetrics and Gynaecology. 2005 Mar;112(3):293-8.