Complications associated with multiple pregnancy -The higher perinatal mortality associated with twinning is largely due to complications of pregnancy, such as: - the preterm onset of labour, - IUGR - complications at birth.

-There is a six-fold increase in perinatal mortality comparing twins to singletons The management of multiple pregnancy is concerned with the prevention, early detection and treatment of these complications.

Polyhydramnios - acute polyhydramnios may occur as early as 16 weeks. - It may be associated with fetal abnormality but is more likely to be due to twin-to-twin transfusion syndrome (TTTS), which can also be known as feto-fetal transfusion syndrome (FFTS).

Twin-to-twin transfusion syndrome -Twin-to-twin transfusion syndrome (TTTS) can be acute or chronic. -The acute form usually occurs during labour and is the result of blood transfusing from one fetus (donor) to the other (recipient) through vascular anastomosis in a monochorionic placenta. -Both fetuses may die of cardiac failure if not treated urgently

-Chronic TTTS occurs in about 15% of monochorionic twin pregnancies and accounts for 15% of perinatal mortality in twins ( The placenta in TTTS transfuses blood from one twin fetus to the other. These cases are characterized by one or more deep unidirectional arteriovenous anastomoses. This results in anaemia and growth restriction in the donor twin (stuck twin) and polycythaemia with circulatory overload in the recipient twin (hydrops). The fetal and neonatal mortality is high but infants may be saved by early diagnosis and prenatal treatment with either amnioreduction, which may have to be repeated regularly as fluid can reaccumulate rapidly , or laser ablation therapy of communicating placental vessels, or septostomy .

-The midwife should always be alert to the woman who complains of a rapid increase in her abdominal girth in the second trimester, as well as a uterus that feels hard and uncomfortable continuously. -The skin over the uterus may look shiny and tight; this is usually due to polyhydramnios and if not treated urgently can cause preterm labour.

C a se hist o r y 2 A 26-year-old primigravida's early scan showed MCDA twins. The mother read on the Internet that problems can be associated with MCDA pregnancy and was very worried about TTTS. From 16 weeks, she had 2-weekly scans for signs of TTTS and growth discordancy. At 20 weeks, she noticed a rapid increase in abdominal size and her tummy was hard and uncomfortable. Her local hospital referred her to the Centre for Fetal Care (CFC) at a tertiary level hospital, where type 2 TTTS was diagnosed. Immediate treatment was amnio-reduction of over 2 litres and laser ablation of connecting blood vessels. Her care was transferred to CFC for weekly scans. Here she mainly saw doctors and felt she missed out on midwife contact. Unfortunately at 32 weeks she was diagnosed as type 3 TTTS, with very abnormal Dopplers in the donor twin. Steroid injections were given and an emergency caesarean section was performed at 33 weeks. Both babies were born in a fair condition and were admifed to the NICU. The mother was encouraged to hand express her milk as soon as she felt well enough, to continue 2–3-hourly during the day and on the 6th day she started expressing using an electric pump. The twins were able to go to the breast aher 2 weeks and started sucking for very short periods. Progress continued and both babies were discharged home at 5 weeks of age, fully breastfeeding.

Fetal malformations This is particularly associated with monochorionic twins.

Conjoined twins -This extremely rare malformation of monozygotic twinning results from the incomplete division of the fertilized oocyte; -it occurs once in 50 000 births and over half the cases are stillborn. -Birth has to be by CS. The site and extent of fusion of the fetuses are infinitely variable. Thoracopagus (conjoined twins united at the thorax) is the commonest form of fusion (over 70% of cases).

The feasibility of separating conjoined twins depends on the site and extent of fusion and the degree to which organs are shared (Oleszczuk and Oleszczuk 2005). Many conjoined twins can now be successfully separated. Others pose major ethical dilemmas – particularly if one can be saved at the expense of the other (Mifflin 2001).

Twin reversed arterial perfusion -Twin reversed arterial perfusion (TRAP) occurs in about 1 in 30 000 births. -In TRAP, one twin presents without a well-defined cardiac structure and is kept alive through placental anastomoses to the circulatory system of the viable fetus

Fetus-in-fetu In fetus-in-fetu (endoparasite), parts of a fetus may be lodged within another fetus; this can happen only in MZ twins

Malpresentations Although the uterus is large and distended, the fetuses are less mobile than may be supposed. They can restrict each other's movements, which may result in malpresentations ), particularly of the second twin. After the birth of the first twin, the presentation of the second twin may change.

Preterm rupture of the membranes Malpresentations due to polyhydramnios may predispose to preterm rupture of the membranes

Cord prolapse -This too is associated with malpresentations and polyhydramnios and is more likely if there is a poorly fifing presenting part. -The second twin is particularly at risk of cord prolapse

Prolonged labour Malpresentations are a poor stimulus to good uterine action and a distended uterus is likely to lead to poor uterine activity and consequently prolonged labour

Monoamniotic twins -Approximately 1% of MZ twins share the same amniotic sac. Monoamniotic (MCMA) twins risk cord entanglement with occlusion of the blood supply through the umbilical cords to one or both fetuses. In some centres this is treated with sulindac, which reduces the amniotic fluid levels, and birth is usually around 32–34 weeks and by elective CS.

Locked twins -This is a very rare but serious complication of twin pregnancy. -There are two types. One occurs when the first twin presents by the breech and the second by the vertex; the other when both are vertex presentations -In both instances, the head of the second twin prevents the continued descent of the first. Primigravidae are more at risk than multiparous women.

Delay in the birth of the second twin -After the birth of the first twin, uterine activity should recommence within 5 minutes. Ideally, as stated previously, the birth of the second twin should be completed within 45 minutes of the first twin being born but with close monitoring can be extended if there are no signs of fetal compromise. Poor uterine action as a result of malpresentation may be the cause of delay. The risks of such delay are intrauterine hypoxia, birth asphyxia following premature separation of the placenta and sepsis as a result of ascending infection from the first umbilical cord, which lies outside the vulva.

After the birth of the first twin the lower uterine segment begins to reform and the cervical canal may have to dilate fully again. The midwife may need to ‘rub up’ a contraction and put the first twin to the breast to stimulate uterine activity. - If there appears to be an obstruction, medical aid is summoned and a CS may be necessary. If there is no obstruction, oxytocin infusion may be commenced or forceps-assisted birth considered.

Premature expulsion of the placenta -The placenta may be expelled before the birth of the second twin. In dichorionic twins with separate placentas, one placenta may be delivered separately; in monochorionic twins the shared placenta may be expelled. The risks of severe asphyxia and death of the second twin are very high. Haemorrhage is also likely if one twin is retained in utero as this prevents adequate retraction of the placental site.

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Postpartum haemorrhage Poor uterine tone as a result of overdistension or hypotonic activity is likely to lead to postpartum haemorrhage -There is also a much larger placental site to contract down.

Undiagnosed twins -The possibility of an unexpected, undiagnosed second baby (in the UK this is unlikely with ultrasound scanning) should be considered if the uterus appears larger than expected after the birth of the first baby or if the baby is surprisingly smaller than expected. If an uterotonic drug has been given after the birth of the anterior shoulder of the first baby, the second twin is in great danger of birth asphyxia and birth should be expedited.

The midwife must break the news of undiagnosed twins gently to the parents. These parents will require special support and guidance during the postnatal period.

Delayed interval birth of the second twin -There have been several reported cases where the first twin has been born, often very prematurely, and then a long gap before labour recommences; it can be days or even weeks before the second twin is born

-This opportunity can be used to give antenatal corticosteroids to the mother to help mature the lungs of the second twin. Careful observations of the mother's condition must be made during this time for signs of infection and fetal compromise. The mother will need additional support from the midwives to cope with her anxieties for her preterm baby on the NICU, which may not survive, or time to grieve if the baby has died, as well as still being pregnant and her concerns for the outcome of her pregnancy.

Postnatal period Care of the babies -Immediate care after the birth is the same as for a single baby. Maintenance of body temperature is vital, particularly if the babies are small; use of overhead heaters will help to prevent heat loss. Identification of the babies should be clear and the parents given the opportunity to check the identity bracelets and cuddle the babies. The babies may need to be admitted to the NICU from the labour suite, otherwise they can be encouraged to have skin-to-skin contact, and go to the breast if they are to be breastfed before being transferred to the postnatal ward with their mother.

Temperature control -Maintenance of a thermoneutral environment is essential, particularly for babies in the NICU. American studies have shown that a sick baby can benefit from sharing the incubator with its twin -Clothing should be light but warm, and allow air to circulate.

Feeding -The mother may choose to feed her babies by breast or with formula milk, but whatever her choice, the midwife must support her in her decision. With breastfeeding, both babies may be breastfed separately or simultaneously. -In the initial postnatal days, it is recommended she breastfeeds her twins separately, as this gives her time to get to know each baby individually and to feel confident in her ability to cope.

If the babies are SFGA or preterm, the paediatricians may recommend that the babies be ‘topped up’ after a breastfeed. Expressed breastmilk is best for these babies. If the babies are not able to suck adequately at the breast the mother should be encouraged to express her milk regularly.

Expressing should be initiated ideally within 6 hours of birth, then regularly every 2–3 hours during the day and once at night or on average 8 times per 24 hours. In some NICUs with a Millbank donor milk may be offered to preterm babies, this reduces the risk of necrotizing enterocolitis (NEC) As twin babies are more likely to be preterm or SFGA, their ability to coordinate the sucking and swallowing reflexes may be poor. If so, they may need to be fed intravenously or by nasogastric tube, depending on their size and general condition. The mother should be

encouraged to participate in whatever method is used. - Careful monitoring of weight gain is required. -Hypoglycaemia may occur and regular capillary blood glucose estimations may be needed. -In the early postnatal days, mothers often worry that their milk supply is inadequate for two babies. - The midwife should reassure her that lactation responds to the demands made by the babies sucking at the breast or expressing

The more stimulation the breasts are given, the more milk she will produce. At feeding times, the midwife must be with the mother to offer support and advice on positioning and fixing the babies ( Fig. 14.5), as well as encouraging her in her ability to cope with breastfeeding two babies.