Women expecting twins or triplets should be offered closer monitoring, including extra scans, according to new NHS guidelines.
Health watchdog NICE has drawn up recommendations for antenatal care in multiple pregnancies, amid evidence standards vary in England and Wales.
Mothers-to-be should be referred to specialist teams and receive a minimum of six scans, says NICE.
Charities say the guidelines will give mothers reassurance about their care.
Multiple births are on the rise, due mainly to an increase in the number of couples having IVF. They now account for 3% of births.
Until now, there have been no clear guidelines for women expecting twins or triplets in England and Wales, leading to differences in care, including the number and timing of scans, planned delivery dates, and the use of measures, such as bed rest, to prevent early labour.
Dr Fergus Macbeth, director of the centre for clinical practice at The National Institute for Health and Clinical Excellence (NICE), said: "We know there is a real clinical need for this guideline because NHS antenatal care for women expecting twins or triplets appears to vary considerably across England and Wales.
"For example, not all women with multiple pregnancies are cared for in dedicated settings such as 'twin clinics' or by multidisciplinary teams of healthcare professionals.
"This can lead to higher than necessary rates of assisted birth and Caesarean sections and also means that women are not appropriately assessed for possible risks during pregnancy.
"Although many women will have a normal pregnancy and birth, it is well known that there are higher risks involved for these types of pregnancy and so it is important to get it right."
The guidance says women expecting twins or triplets should receive at least six scans, and sometimes as many as 11.
A scan should be carried out at between 11 and 14 weeks to assess whether twins share a placenta, which can increase the risk of complications.
NICE said women at risk of going into labour early should not be routinely offered bed rest or drugs to prevent labour as there was no evidence that they work.
In addition, the guidelines provide recommendations on when a planned birth should be offered.
They do not look at women who are pregnant with four or more babies.
Dr Virginia Beckett, from the Royal College of Obstetricians and Gynaecologists, welcomed the guidelines. She said increased monitoring and contact with healthcare workers would help ensure the mother and their babies received the best care possible.
"A multi-disciplinary approach including input from midwives, obstetricians and ultrasonographers will help ensure any complications are picked up early," she said.
Jane Denton, director of the Multiple Births Foundation, said: "Although much of the care at present is very good, there are many inconsistencies and often poor co-ordination between healthcare professionals if mothers are referred to other hospitals.
"These recommendations address all of these concerns and will give mothers confidence that they are receiving the highest standard of care, appropriate to their individual needs."