Anencephaly is a defect in the closure of the neural tube during the fourth week of gestation, occurring in 4.7/10 000 births (Collins et al, 2013). The neural tube is a narrow channel that folds and closes between 24–26 days post-fertilisation to form the brain and spinal cord of the embryo (Coady and Bower, 2015). Anencephaly occurs when the cephalic or head end of the neural tube fails to close, resulting in the absence of a major portion of the brain, skull and scalp. Infants with this disorder are born without a forebrain and cerebrum (the thinking and coordinating part of the brain). The remaining brain tissue is often exposed, not covered by bone or skin (Stumpf et al, 1990; Tasker et al, 2013). A baby born with anencephaly is unconscious and will usually demise shortly after birth. Although some individuals with anencephaly may be born with rudimentary brain stem, the lack of a functioning cerebrum permanently rules out the possibility of ever gaining consciousness. Reflex actions, such as breathing and response to sound or touch, may occur (Rodeck and Whittle, 2009).
The cause of anencephaly is unknown, but it is thought that a mother's diet and vitamin intake may play a role. Scientists believe that many other factors are also involved. Studies have shown that adding extra folic acid to the diet of women of childbearing age may significantly reduce the incidence of neural tube defects such as anencephaly. Therefore, it is recommended that all women of childbearing age take 400 mcg of folic acid daily for 3 months before conception, continuing to 12 weeks' gestation, and 5 mg daily for women with a previously affected baby or those who are taking anticonvulsants (Nelson-Piercy, 2015).
Treatment and outcome
There is no cure or standard treatment for anencephaly. Treatment is supportive only (National Institute of Neurological Disorders and Stroke, 2015). The outcome for infants born with anencephaly is extremely poor. If the infant is not stillborn, then he or she will usually demise within a few hours or days after birth (Rodeck and Whittle, 2009).
Case presentation
This article will discuss two cases of anencephaly which occured consecutively at the same hospital. In both cases, the parents decided to continue their pregnancies till term, with the intention of donating their infants' tissue/organs.
Case 1 (2012)
A pregnant woman aged 35 years presented for shared antenatal care, with a background history of a previous caesarean section for growth restriction. Regarding this pregnancy, the anencephalic fetus was diagnosed at 12 weeks' gestation, and counselling was performed by a consultant obstetrician and a midwife. A final decision was made by the woman and her partner to continue the pregnancy until full term, even though they were fully aware about the extremely poor outcome. They wished to donate the baby's tissues/heart valves at birth. A multidisciplinary team was set up comprising an obstetrician, an antenatal screening midwife, a community midwife, a paediatrician and a regional organ transplant coordinator, to support and aid the couple's wishes. The organ transplant coordinator developed a paediatric donation plan with the couple to arrange for the heart valves to be retrieved within 24 hours of the infant's death.
‘Preventive measures for anencephaly include proper nutrition and periconceptual folic acid supplementation’
Labour was induced with dinoprostone 10 mg at 42 weeks, and the woman gave birth vaginally to an anencephalic male baby with no complications, weighing 2.01 kg. The baby demised 3 hours later. Successful retrieval of the heart valves was undertaken. The mother's recovery was uneventful, with no physical complications in the postnatal period.
Subsequently, in 2014, the woman became pregnant again and successfully gave birth to a live male infant by spontaneous vaginal birth.
Case 2 (2014)
The second case was a 30-year-old woman who booked at 8 weeks' gestation in her second ongoing pregnancy. She had an uneventful first pregnancy and no relevant past medical or family history. Her 12-week ultrasound scan revealed anencephaly. Counselling had been done early, at 12 weeks' gestation, and the woman and her partner wished to continue the pregnancy with the plan for organ donation, hopefully retrieving both the heart valves and kidneys. The same multidisciplinary team as worked in the first case (above) was set up to support and assist this couple, and a plan of care developed.
Labour was induced with dinoprostone 10 mg at 40 weeks in order to coordinate optimum timing of birth with the regional surgical team. After a lengthy induction process, the woman gave birth vaginally to an anencephalic female baby with face presentation, weighing 2.42 kg. The baby demised within 1 hour of birth. The tissue services team, who had already been informed, liaised with the delivery suite, and retrieval of the heart valves was successful. However, it was not possible to donate the kidneys due to the long labour and the length of time lapsed.
Discussion
Anencephaly is one of the three major neural tube defects that results from failure of the neural tube closure nearly 4 weeks after conception (Rowan-Hull, 2013). It is a severe defect and is not compatible with survival. Infants that are alive at birth generally die within hours, but can occasionally survive for a few days or weeks (Rodeck and Whittle, 2009).
Anencephaly can be reliably diagnosed antenatally, with a high degree of certainty (Johnson et al, 1997; Sadler, 2012). The initial screening for anencephaly and other neural tube defects is by ultrasonography and fetal magnetic resonance imaging (MRI). The sonographic diagnosis is primarily based on the absence of the brain and calvarium superior to the orbits on coronal views of the fetal head. Polyhydramnios occurs in 35% of the cases. The anomaly can be accurately detected and diagnosed on fetal ultrasound obtained between 11–14 weeks' gestation (Chundrupatla and Swargam, 2014).
A fetus with this type of neural tube defect lacks a functioning cerebrum, which rules out the possibility of having consciousness. The infant will be blind, deaf and unable to feel pain. The prognosis is extremely poor and so most women and their partners decide to opt for termination of pregnancy after detailed counselling. In the two cases reported here, the women did not wish for termination and instead wished to give birth to their babies at term in order for organ donation. It is remarkable that two such similar cases presented consecutively in the district general hospital setting.
Preventive measures include proper nutrition and periconceptual folic acid supplementation. Eating nutritious foods and taking vitamin supplementation with 400 mcg of folic acid before and up to 12 weeks of pregnancy may help prevent neural tube birth defects (Nelson-Piercy, 2015). Dietary sources of folic acid include leafy green vegetables, dried beans and oranges. Some products are fortified with folic acid, including enriched flour, rice and bread. Pregnant women who have previous history of having infants with neural tube defects need to take folic acid supplementation of 5 mg before conception and throughout the first trimester (Usang et al, 2010). Despite various recommendations for folic acid supplementation being issued internationally, barriers exist for implementation and, as a result, the prevalence of neural tube defects did not decrease in Europe during the period 1991–2011 (Khoshnood et al, 2015).
Conclusion
Anencephaly is one of the most common fetal neural tube defects which can be diagnosed by transvaginal scan as early as 11–14 weeks, and previously by elevated second trimester maternal alpha-fetoprotein level. The recurrence risk in future pregnancy is 2–5%, which can be prevented by up to 70% by taking periconceptual folic acid (Chundrupatla and Swargam, 2014). Once it is diagnosed, there is no curative treatment for this condition, but detailed counselling by senior obstetricians or midwives is a key aspect of the management plan. The final decision has to be made by the pregnant woman and her partner, with full support from midwifery and medical staff. It is important to note that not all couples opt for termination of pregnancy.
Despite the anencephalic infant being incompatible with life, organ donation may be considered, although limited in the cases discussed to the retrieval of heart valves, cornea and kidneys. Success rates have varied—and opinion about transplanting small kidneys also varies—but successful transplants are possible (Stumpf et al, 1990). In the past year there has been a case of successful retrieval of kidneys in the UK (BBC News, 2015); sadly, this was not possible in our second case due to the length of labour, despite the original wishes of the parents. In arranging for tissue or organ donation, there is a need for multidisciplinary involvement with relevant staff (as described in the cases above) in order to plan, coordinate and deliver optimal care according to the parents' wishes.