Globally, an estimated 1.6 million twin births occur each year (Monden et al 2021). In 2022, approximately 8619 twins were born in the UK (Office for National Statistics (ONS) 2024). While the incidence of multiple births is rising internationally, attributed to advancements in assisted reproduction techniques (ART), the rates are decreasing in the UK due to the use of elective single embryo and blastocyst transfers, including selective fetal selection (Khalil 2021).

Twin pregnancies confer considerable risks to both mother and baby. Maternal complications, including constipation, backache, heartburn and varicose veins, through to other complications of miscarriage, anaemia, operative birth and postnatal depression, are often more severe in twin pregnancies, because of increased physiological demands (Whittaker et al 2023). Hypertensive disorders are two to three times higher compared to a singleton pregnancy and more likely to occur earlier in pregnancy, and be more severe (Laine et al 2019). For women who are obese, there is an increased risk of hypertensive disease. Excess weight gain during pregnancy is associated with significant risk of gestational diabetes, including preterm birth, macrosomia and intrauterine growth restriction (Lucovnik et al 2015). Maternal risk factors associated with twin pregnancies contribute to higher mortality rates in women from Black and ethnic minority groups compared to a singleton pregnancy (Vousden et al 2024).

Perinatal mortality and morbidity rates are higher for a twin pregnancy compared to a singleton. The MBRRACE-UK report highlights the rising stillbirth rates for twins, triplets and more, and are almost double that compared to a singleton pregnancy (Gallimore et al 2024). Prematurity, congenital anomalies, monochorionicity and growth restriction all contribute to increased perinatal and mortality rates including a six-fold risk of cerebral palsy (Sellier et al 2021). For women over 40 years of age, particularly in pregnancies due to ART, the incidence of stillbirth, preterm birth and admission to neonatal unit is also increased (Xiong et al 2022).

The National Institute for Health and Care Excellence (NICE) guidance sets out key recommendations to enhance effective antenatal care, and prevent adverse maternal and perinatal outcomes (Gibson et al 2020). This paper will review the main complications associated with a twin pregnancy, and the midwifery and obstetric management required to mitigate the consequences of adverse outcomes for mother and baby.