NICE guidance - Multiple pregnancies

This guideline will improve care for women expecting twins or triplets. By Abhijit Bhattacharyya

3D ultrasound scan showing triplets (Photograph: SPL)
3D ultrasound scan showing triplets (Photograph: SPL)

A multiple pregnancy is associated with a higher risk of complications for both mother and baby, including miscarriage, anaemia, hypertension, vaginal bleeding and preterm and operative delivery. Maternal mortality is 2.5 times higher in multiple births than in single births.

Over the past few decades, the incidence of multiple births has increased mainly because of the introduction of assisted reproduction techniques, such as IVF. About 3% of live births are now multiple births.

GPs are therefore encountering more twin and triplet pregnancies, and because they are often the first contact for pregnant women, knowledge about care of these women is vital.

However, until now, the guidelines for antenatal care for women with a multiple pregnancy were not standardised.

The new NICE multiple pregnancy guideline sets clear best practice recommendations in relation to:

  • Determination of gestational age and chorionicity.
  • Nutritional and dietary requirements and support in multiple pregnancy.
  • Specialist care provision with effective utilisation of tertiary level fetal medicine centres.
  • Monitoring for intrauterine growth restriction.
  • Timing of delivery.

Gestational age and chorionicity
Women with twin and triplet pregnancies should be offered a first trimester ultrasound scan when crown-rump length measures from 45mm to 84mm (at approximately 11 weeks zero days to 13 weeks six days).

This is the best time to determine chorionicity (the number of chorionic membranes that surround the fetuses and whether the placenta is shared) and is useful for determining the risk of Down's syndrome.

Instead of naming fetuses as twin one and twin two, fetuses should be named according to their positions (upper, lower or right, left).


At least nine antenatal appointments should be offered for monochorionic, diamniotic twin pregnancies (Photograph: SPL)

Nutritional and dietary requirements
Women with a multiple pregnancy should receive the same advice about nutritional supplements as in routine antenatal care. However, health professionals should be aware of the increased chance of anaemia in these women. A FBC should be offered at 20 to 24 weeks to identify women who need early supplementation with iron or folic acid, and repeated at 28 weeks.

Regarding diet and lifestyle advice, women with a multiple pregnancy should receive the same advice as for women with a singleton pregnancy.

Types of twin pregnancy
  • Dichorionic twins: babies have separate placentas.
  • Monochorionic diamniotic twins: babies share a placenta but have separate amniotic sacs.
  • Monochorionic monoamniotic twins: babies share a placenta and amniotic sac.

Specialist care provision
Not all women with a multiple pregnancy need to be referred to a fetal medicine unit. A specialist care team with experience of multiple pregnancy, comprised specialist obstetricians, specialist midwives, ultrasonographers, perinatal mental health professionals, women's health physiotherapists, infant feeding co-ordinators and dietitians, is capable of managing women with an uncomplicated multiple pregnancy. This will minimise the number of hospital visits and also provide care as close to the woman's home as possible.

It is important that healthcare professionals should not create unnecessary anxiety in women with an uncomplicated multiple pregnancy by organising unnecessary follow-up or tests. Women with pregnancies where there is a shared amnion and pregnancies complicated by discordant fetal growth, fetal anomaly, discordant fetal death or feto-fetal transfusion syndrome should be referred to a tertiary level fetal medicine centre.

Antenatal visits
Women with uncomplicated dichorionic, diamniotic twin pregnancies should be offered at least eight antenatal appointments with a healthcare professional from the core team and at least two appointments should be with the specialist obstetrician. Appointments should be given at the time of the dating scan followed by 16, 20, 24, 28, 32, 34 and 36 weeks.

At least nine antenatal appointments should be offered for monochorionic, diamniotic twin pregnancies.

Trichorionic triamniotic triplet pregnancies should be offered seven visits (this is lower than the number of visits for twin pregnancies because women with triplet pregnancies tend to give birth earlier).

Pregnancies with triplets with a shared placenta (monochorionic or dichorionic) should be offered 11 visits.

Serial ultrasound scans should be used to diagnose intrauterine growth restriction. A 25% or greater difference in size between twins or triplets is an important indicator of intrauterine growth restriction.

Timing of delivery
To reduce the variability of timing of delivery in different delivery units, the NICE guideline considered the best available evidence. Recommendations are outlined in the table below. Women can continue their pregnancies beyond these dates but they should be informed of the risks involved. Women who wish to continue with their pregnancy will require intensive antenatal monitoring.

Summary
This new clinical guideline sets the standard of care which should be provided to women with an uncomplicated multiple pregnancy. This is the first time that NICE has published clear recommendations for the NHS for multiple pregnancy, based on the best available evidence.

Though a multiple pregnancy carries higher risks, most women will have a normal outcome. While doctors need to be vigilant for complications, we should intervene only when necessary. The recommendations in this new guideline will provide clarity for GPs, and improve antenatal care for women expecting twins or triplets.

Timing of delivery
Order/chorionicity Offer elective birth from
Dichorionic twins 37 weeks 0 days
Monochorionic twins 36 weeks 0 days*
Triplets 35 weeks 0 days*
*After offering a course of maternal corticosteroids
  • The new NICE guideline is available in full at www.nice.org.uk/CG129
  • Dr Bhattacharyya is a GP and GP trainer in Solihull, West Midlands, and a member of the guideline development group.

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