It stands to reason that our bodies weren’t designed to carry more baby at once, so the expected gestation for twins is only 37 weeks.  However with the increased risk of pre-eclampsia and other complications, prematurity is more likely in twins than in single pregnancies, as such, parents to be should be prepared for the complications that prematurity may present.

One Born Every Minute: Expecting Twinsby Professor Mark Kilby and Jane Denton, has just arrived on bookshelves all over the UK. A guide to the road through pregnancy and your babies’ first year, the writers and publishers have kindly shared some of their wisdom with NowBaby , including some great information about some of the problems premature babies may experience…


Difficulty in breathing unaided is one of the common complications of prematurity, especially for babies born before 36 weeks. The more premature babies are, the less surfactant is present in their lungs. Surfactant is a substance that coats the tiny alveoli inside the lungs, helping them to stay inflated so that they have the best surface area available for oxygen to pass into the blood in sufficient amounts. If the lungs do not have enough surfactant, they are not able to supply enough oxygen and the babies can develop Respiratory Distress Syndrome (RDS). This affects around half of babies born before 32 weeks, although with proper monitoring, it is successfully treated in almost all babies. The closer to term babies are born, the lower the chances of their developing RDS.


Neonatal jaundice occurs in around half of all newborns, but is particularly common in premature babies, because their livers are immature. When the extra red blood cells that are required when babies are in the womb are broken down after birth, a yellow-coloured pigment called bilirubin is produced and cleared by the liver. When levels of bilirubin are high, it is not processed fast enough and is deposited in the skin, giving it a yellowish tone. Jaundice often begins about four days after birth, and can disappear on its own. If treatment is required, it is done using phototherapy. The baby, wearing only a nappy and protective eye shields, remains in their cot or incubator and a special ultraviolet light is placed close to their skin. Treatment may take several days, and last for a few hours at a time. While jaundice can continue for several weeks after the birth, it usually disappears after two or three weeks.

Maintaining body temperature

Premature babies have less body fat than full-term babies, and are less able to shiver (in order to generate heat for themselves) and to maintain their body temperature. For this reason, they are often placed in incubators at birth to keep them warm until they have grown and developed some fat.


Immature immune systems make premature babies more prone to infections. The risk of infection is one of the main reasons that NNU’s are extremely conscious of hygiene and often allow only parents (and, depending on their particular policy, siblings) to visit.

Sight and hearing

Complications relating to vision and hearing primarily affect babies born before 32 weeks and those with a birth weight below 1,500 g, although only about one in four of these babies suffers from these problems. Nonetheless, babies will be given a hearing test before they leave hospital. In the case of their sight, once they reach a certain stage of maturity, they will be screened weekly or fortnightly to ensure that any potential problems can be avoided or minimised.

Brain and neurological complications

Ultrasound scans of premature babies’ brains are often performed soon after they are admitted to the NNU, and subsequently on a regular basis, because they are vulnerable to small bleeds from the tiny blood vessels in their developing brain. The brain and nervous system of babies born after
30 weeks are more mature and, if they have a good weight for gestational age and have no underlying health issues, it is unusual for babies to suffer from any serious neurological problem caused by these bleeds.

Babies born before 30 weeks, especially those that are small for gestational age (see below) or with fetal growth restriction, are at greater risk of a bleed in the brain. The majority of babies born before 30 weeks will recover from a bleed with little or no long-term neurological consequences. For some, however, their developmental progress may be affected (e.g. they may suffer from cerebral palsy). Some need educational support and have a range of other, more subtle difficulties. It is important that the progress of the babies is monitored, so that any problems in reaching their developmental milestones (e.g. walking, speech) can be identified and treated as soon as possible.

This is an edited extract from One Born Every Minute: Expecting Twins? by Professor Mark Kilby and Jane Denton, published by Quadrille, £25.