Twins or triplets occur in approximately 1 in 60 pregnancies (16 in every 1,000 women giving birth in 2015 had a multiple birth), and 3% of live-born babies are from multiple gestations. The incidence of multiple births has risen in the past 30 years. This is due mainly to increasing use of assisted reproduction techniques, including in vitro fertilisation (IVF), and also to changing demographics as women defer pregnancy and twins are more common at later ages (102 in every 1,000 women giving birth in 2015 were aged 45 or over).

Women with a twin or triplet pregnancy are at higher risk compared with women with a singleton pregnancy. Adverse outcomes are more likely, both for the woman and her babies, during the prenatal and intrapartum periods. Because of this, women need increased monitoring and more contact with healthcare professionals during their pregnancy.

Assessment and planning start as soon as the twin or triplet pregnancy is detected and continue throughout pregnancy at each antenatal contact. Determining the chorionicity and amnionicity of the pregnancy allows the risk to be stratified and the number of antenatal visits and ultrasound examinations to be planned. It is important that ultrasound surveillance is carefully scheduled to monitor for complications including selective fetal growth restriction, feto-fetal transfusion syndrome and twin anaemia polycythaemia sequence (TAPS).

Identifying complications earlier means that decisions can be made promptly about referring the woman to a tertiary level fetal medicine centre. It also informs discussions with women in their second and third trimesters about their hopes and wishes in relation to timing and mode of birth, and the management of the intrapartum period (including fetal monitoring, analgesia and the third stage of labour).

This guideline replaces the previous NICE guideline on multiple pregnancy (CG129). The surveillance process found new evidence and identified a need to include intrapartum care, an area that was not included in the original guideline. In current practice, a significant proportion of multiple pregnancy losses occur intrapartum and the risk of adverse perinatal outcomes is greater in multiple than in singleton pregnancies.

The guideline updates recommendations on screening and monitoring for selective fetal growth restriction and feto-fetal transfusion syndrome, and makes new recommendations on screening and monitoring for TAPS; screening for and preventing preterm birth; and timing of birth. New recommendations on intrapartum care cover mode of birth, fetal monitoring, analgesia and managing the third stage of labour.