Maternal phenylketonuria collaborative study, obstetric aspects and outcome: the first 6 years

Reproductive experience of women living with phenylketonuria

Introduction

Many women with PKU are well-informed about the risks of maternal PKU but there are several barriers to achieving satisfactory metabolic control before and during pregnancy. Many studies have documented the outcome of maternal PKU infants, but very little has been reported about the experiences of women of reproductive age with PKU, particularly about their psychosexual development, pre-conception, pregnancy and postnatal experience.

Methods

In the UK, in a subsection of an online questionnaire conducted by the National Society for PKU (NSPKU) about living with PKU, women aged 18 years and over completed 9 closed questions about their pre-conception, pregnancy and post-natal experiences and an open-ended question on their reproductive health.

Results

300 women aged 18 years and over with PKU completed this questionnaire with 37% (n = 111/300) of women already having children. 56% (n = 71/128) of pregnancies were planned and a further 18% (n = 23/128) of women had both planned and unplanned pregnancies. Most women (73%, n = 200/273) expressed concerns, fears and distress about pregnancy and two thirds of women who had at least one pregnancy stated that having PKU made pregnancy more stressful and difficult. 60% (n = 164/273) were concerned that they may cause harm to a baby, 58% (n = 159/273) worried about their ability to manage a strict diet during pregnancy, 54% (n = 147/273) had anxiety about their ability to maintain blood Phe within target range, and 48% (n = 132/273) feared having an unplanned pregnancy.

Postnatally, 48% (n = 45/93) had low mood or sadness, 41% (n = 38/93) were depressed, 34% (n = 32/93) felt unable to cope, 33% (n = 31/93) said they could not manage their PKU and care for their baby, 14% (n = 13/93) struggled with child care needs and 4% (n = 4/94) worried they might hurt themselves or their baby through being unable to manage their diet.

Conclusions

Many women with PKU have unmet sexual and reproductive health needs. Pregnancy fears are prominent from adolescence onwards and for some women overarching concerns about their ability to cope with pregnancy led to a decision not to have children. Interventions are needed to reduce the psychological impact of the risk of maternal PKU syndrome and assist with safe pregnancies. Post-natal experiences of women with PKU give rise to concern.

The clinical content of preconception care: women with chronic medical conditions

This article reviews the medical conditions that are associated with adverse pregnancy outcomes for women and their offspring. We also present the degree to which specific preconception interventions and treatments can impact the effects of the condition on birth outcomes. Because avoiding, delaying, or achieving optimal timing of a pregnancy is often an important component of the preconception care of women with medical conditions, contraceptive considerations particular to the medical conditions are also presented.

Infusionstherapie und Ernährung von Risikogruppen

Besondere Situationen erfordern ein besonderes Vorgehen. Während bisher das »Standardvorgehen« bezüglich der Ernährung von pädiatrischen Patienten dargestellt wurde, beschäftigt sich das vorliegende Kapitel mit »Sondersituationen« der pädiatrischen Infusionstherapie und Ernährung. Behandlungssituationen, die ein besonderes Vorgehen bei der Therapie oder spezielle Aufmerksamkeit bei der Anpassung der Ernährung erfordern, entstehen in der Regel durch 4 mögliche Situationen:

spezifische Physiologie von Patientengruppen (z. B. Früh- oder Neugeborene),

Auswirkungen von therapeutischen Maßnahmen (z. B. Operationen),

Pathophysiologie von Erkrankungen (z. B. angeborene Stoffwechselerkrankungen, Erkrankungen des onkologischen, rheumatischen oder atopischen Formenkreises, Anorexia nervosa, Bulimie oder Adipositas) oder

besondere körperliche Belastungen [z. B. (Leistungs-)Sport].

Bekannte Strategien werden systematisch und prägnant dargestellt und diskutiert.

Die Beschäftigung mit der Ernährung von »Risikogruppen« übt das Erkennen und den Umgang von potenziellen Gefahrensituationen bei der Verordnung von bilanzierter Ernährung. So sollte auch derjenige von dem Kapitel profitieren, der sich mit den behandelten Patientengruppen, Situationen, Erkrankungen üblicherweise nicht beschäftigen muss.

Preconceptional health promotion: progress in changing a prevention paradigm

Preconceptional health promotion is a proven strategy to impact reproductive outcomes. Despite energy to incorporate this prevention strategy into the care of women in this country, little evidence exists that the paradigm shift necessary to reframe the clinical care of women has occurred or that public awareness about critical opportunities for preventing reproductive casualties is high. This article reviews the rationale for preconceptional counseling, discusses progress in moving the agenda of prepregnancy wellness forward, and reveals some of the lessons learned from efforts to redesign prevention emphases for reproductive healthcare.

Maternal phenylketonuria in Western Australia: pregnancy outcomes and developmental outcomes in offspring

OBJECTIVE

To examine the outcomes of phenylketonuric (PKU) pregnancies in Western Australia including birth characteristics and cognitive and behavioural outcomes in offspring.

METHODS

A cross-sectional study of women and their offspring who were identified from the Western Australian Maternal PKU Program (WAMPKUP) from 1991 to 2000 was carried out. Cognitive assessments (K-BIT or Griffiths scales) were conducted on women and their children, and behavioural assessments (CBCL) were conducted on the children.

RESULTS

Thirty pregnancies by nine women were registered on the WAMPKUP between 1991 and 2000. There were 16 live births, with one preterm delivery at 32 weeks. There were no congenital abnormalities. Five of the nine mothers and their nine children (aged 18 months-10 years) participated in developmental assessments. A linear relationship was shown between lower maternal IQ scores and later attainment of metabolic control in pregnancy (rs = -0.828; P = 0.01). There was significant correlation between lower offspring IQ scores and later attainment of metabolic control in pregnancy (rs = -0.734; P = 0.02). Correlation between maternal and offspring cognitive scores was not significant. Four of nine (44%) children rated in the clinical range for behavioural problems. Compared to children with no behavioural difficulties, these children had lower cognitive abilities (P = 0.05) and maternal metabolic control during pregnancy was poor (P = 0.05).

CONCLUSIONS

Poor metabolic control in pregnancy is associated with poorer cognitive outcomes and increased behavioural difficulties in offspring of mothers with PKU. The results have implications for the implementation of appropriate dietary measures before conception in PKU pregnancies, and indicate a need for the establishment of multidisciplinary teams to follow up individuals with PKU to communicate the importance of pregnancy planning, to manage PKU pregnancies, and to follow up the offspring.

Nutrient intake and congenital heart defects in maternal phenylketonuria

OBJECTIVE

The purpose of this study was to determine whether nutritional components other than high maternal blood phenylalanine levels (> or = 10 mg/dL) are associated with congenital heart defects in the offspring of women with hyperphenylalaninemia.

STUDY DESIGN

Of the 414 subjects who had live births, 249 women (60.1%) started diet treatment before 8 weeks of gestation and had nutritional assessments and infant outcome data. Maternal phenylalanine levels, protein intake, and the incidence of congenital heart defects were determined. Simple contingency table analysis was done by chi(2) and Fisher exact test.

RESULTS

A significantly increased incidence of congenital heart defects was observed in offspring of mothers with hyperphenylalaninemia who had an elevated blood phenylalanine level >10 mg/dL at 0 to 8 weeks of gestation and a protein intake of < or = 50% of the recommended dietary allowance (P <.0013).

CONCLUSION

An inadequate intake of protein during pregnancy in conjunction with elevated blood phenylalanine levels appear to have an additive effect in the incidence of congenital heart defects in the offspring of women with hyperphenylalaninemia.

Barriers to successful dietary control among pregnant women with phenylketonuria

PURPOSE

The teratogenic effects of maternal PKU are preventable, yet affected babies continue to be born. This study's purpose was to identify barriers to successful dietary control among pregnant women with PKU.

METHODS

An interview-based study was conducted of women with PKU who were known to metabolic disease clinics in three states and pregnant during 1998 to 2000. Medical records were used to document timing of metabolic control.

RESULTS

Of 24 women in the study, only 8 (33%) initiated the diet before pregnancy. Of 22 medical records received, only 12 (55%) indicated control of blood phenylalanine levels before 10 weeks' gestation. Risk factors for late dietary control included young age and belief that treatment costs complicated the diet. Although all of the women expressed confidence in the metabolic clinic staff, few perceived their obstetricians were knowledgeable about the maternal PKU diet. Of 13 women enrolled in state-based assistance programs, 9 (69%) reported proof of pregnancy was required for eligibility. Many women using private insurance reported their insurers were unwilling to pay for medical foods. When the data were stratified according to state of residence, differences were observed in the rate of live-born infants, prepregnancy medical food use, average travel time to the metabolic clinic, and gestational week when metabolic control was achieved.

CONCLUSION

Our study's findings may be used to target educational messages to women with PKU and to direct future research directions. For example, obstetric knowledge of maternal PKU needs further evaluation. Discrepancies should be resolved between maternal PKU medical recommendations and the policies of third party-payers. The disparities in financial assistance and services available to pregnant women with PKU residing in different states should be examined further.

Genetic implications for newborn screening for phenylketonuria

The genetic implications for PKU are similar to those for any inherited disorder, but require an intimate knowledge of the dietary care required by these women. Unfortunately, today most women with PKU have discontinued dietary treatment by adulthood and find the restricted phe diet onerous and difficult. Fortunately, this is changing. "Diet for life" is the usual, although not yet universally, adopted practice today, but even so, there are women who conceive "off diet." This inhibits intellectual development of the fetus. If intensive services are provided for such women, fetal outcome can be improved by good blood phe control between 120 and 360 uM/L. Although prenatal diagnosis is available by fetal mutation studies, many women today resist the benefits of genetic counseling. Unfortunately, insurance companies often are unwilling to pay for such procedures as mutation analysis or the provision of low phe diets. Overall, public policy for the care of women with genetic disorders is in a state of flux and strong leadership is required to improve services.

American Academy of Pediatrics: Maternal phenylketonuria

Elevated maternal phenylalanine levels during pregnancy are teratogenic and may result in growth retardation, significant psychomotor handicaps, and birth defects in the offspring of unmonitored and untreated pregnancies. Women of childbearing age with all forms of phenylketonuria, including mild variants such as hyperphenylalaninemia, should receive counseling concerning their risks for adverse fetal effects optimally before conceiving. The best outcomes occur when strict control of maternal phenylalanine levels is achieved before conception and continued throughout the pregnancy.

Maternal phenylketonuria: an international study

Maternal phenylketonuria (PKU) syndrome results in multiple congenital anomalies in the offspring, usually consisting of microcephaly, intrauterine growth retardation, dysmorphology, and congenital heart disease. Pregnancies treated preconceptionally with a phenylalanine-restricted diet and control of maternal blood phenylalanine levels within the recommended range result in normal offspring. However, in this 15-year study, several significant factors resulted in microcephaly in 27% of the offspring, and 7% exhibited serious congenital heart disease. These results occurred chiefly in women with mean IQ scores of 83 associated with low socioeconomic status and decreased educational achievement. Another important factor associated with suboptimal control of blood phenylalanine levels during pregnancy was the fact that most pregnancies were not carefully planned and occurred in women off dietary treatment with phenylalanine-restricted products. These results indicate that greater effort must be developed to assist women with PKU in remaining on diet during their reproductive years. It appears that continued adherence to the diet, resulting in normal maternal intelligence, is an important contribution to improved fetal development.

Importance of diet in maternal phenylketonuria

Diet has long been recognized as the primary treatment modality for individuals with phenylketonuria (PKU) during infancy and childhood. Recent findings from the Maternal PKU Collaborative Study clearly indicate that dietary restriction of phenylalanine is also necessary to prevent the adverse effects of an elevated plasma phenylalanine concentration during pregnancy, which include microcephaly, physical anomalies, and mental retardation.

The international study of pregnancy outcome in women with maternal phenylketonuria: report of a 12-year study

OBJECTIVE

The purpose of this report was to update the results of the Maternal Phenylketonuria Collaborative Study, which was established to assess the efficacy of a phenylalanine-restricted diet in preventing morbidity among the offspring of women with hyperphenylalaninemia.

STUDY DESIGN

During a 12-year period 576 women with hyperphenylalaninemia were enrolled in this study. Outcome measures were stratified according to classification of maternal hyperphenylalaninemia and the time at which dietary control of phenylalanine level was achieved.

RESULTS

Optimal physical and cognitive fetal outcomes occurred when maternal blood phenylalanine level <600 micromol/L was achieved by 8 to 10 weeks' gestation and maintained throughout pregnancy (trimester average, </=600 micromol/L).

CONCLUSIONS

The achievement of blood phenylalanine level control through a phenylalanine-restricted diet significantly diminished the occurrence of congenital abnormalities among offspring of women with hyperphenylalaninemia and improved early intellectual progress of these offspring.

Maternal phenylketonuria syndrome: congenital heart defects, microcephaly, and developmental outcomes

OBJECTIVE

A cohort of women with phenylketonuria (PKU) were selected to explore the impact of phenylalanine (Phe) levels and other factors on congenital heart defects (CHDs), microcephaly, and development of their offspring.

STUDY DESIGN

Three hundred fifty-four women with PKU were followed up weekly with diet records, blood Phe levels, and sonograms obtained at 18 to 20 and 32 weeks' gestation. At birth, 413 offspring were examined and followed up at 6 months and annually by means of Bayley Mental Developmental Index and Psychomotor Developmental Index tests at 1 and 2 years. The women had Wechsler Adult Intelligence Scales and DNA testing.

RESULTS

Thirty-one offspring had CHDs; of these, 17 also had microcephaly. Mean Phe levels at 4 to 8 weeks' gestation predicted CHDs (P <.0001). An infant with a CHD had a 3-fold risk of having microcephaly when the mother had higher Phe levels (P =.02). The Bayley Mental Developmental Index and Psychomotor Developmental Index scores correlated with both CHDs (P =.037 and.0015, respectively) and microcephaly (P =.0001 for both). No direct relationship to the PKU mutation was found.

CONCLUSION

None of the women whose offspring had CHDs had blood Phe levels in control during the first 8 weeks of gestation. Women with PKU need to be well controlled on a low-phenylalanine diet before conception and throughout pregnancy.

Management of phenylketonuria for optimal outcome: a review of guidelines for phenylketonuria management and a report of surveys of parents, patients, and clinic directors

OBJECTIVE

The development of guidelines for phenylketonuria (PKU) management in the United Kingdom has resulted in much discussion in the community of parents and PKU clinics and parents have asked why the United States does not have such guidelines. The objective of this report is to discuss PKU management in the United States, the British guidelines on PKU management, and the feasibility, suitability, and mechanism of developing PKU management guidelines in the United States.

METHODS

Members of the American Academy of Pediatrics (AAP) Committee on Genetics (COG) reviewed the literature and conducted surveys of parents of children with PKU, young adults with PKU, and directors of PKU clinics in the United States. A meeting was held at the National Institute of Child Health and Human Development to review the AAP/COG efforts at reviewing the status of PKU management and guideline development in the United States.

RESULTS

The British guidelines are more stringent than the PKU management practices in many parts of the United States. Evidence exists that stricter management improves developmental outcome. The parents who responded to the surveys indicated willingness to comply with more stringent dietary management if that would improve outcome. They also identified problems that make such management difficult. The clinic directors supported the timeliness of the review. Some had begun a trend toward more stringent control of blood phenylalanine concentrations, at least in the first 4 years of life.

CONCLUSION

The AAP Committee on Genetics will complete its subject review of the management of PKU. Guidelines for care of PKU in the United States probably would look quite similar to the existing guidelines in other countries. The parents surveyed supported more stringent PKU management, but information from a broader distribution of parents would provide a more representative view. The status of the US health care system creates problems for improved PKU management in the United States that do not exist in the countries already following stricter guidelines.

Relationship among genotype, biochemical phenotype, and cognitive performance in females with phenylalanine hydroxylase deficiency: report from the Maternal Phenylketonuria Collaborative Study

OBJECTIVE

To examine the relationship of phenylalanine hydroxylase (PAH) genotypes to biochemical phenotype and cognitive development in maternal phenylketonuria (PKU).

METHODOLOGY

PAH gene mutations were examined in 222 hyperphenylalaninemic females enrolled in the Maternal PKU Collaborative Study (MPKUCS). A total of 84 different mutations were detected, and complete genotype was obtained in 199 individuals. Based on previous knowledge about mutation-phenotype associations, 78 of the mutations could be assigned to one of four classes of severity (severe PKU, moderate PKU, mild PKU, and mild hyperphenylalaninemia [MHP]). Then, 189 MPKUCS subjects were grouped according to the various combinations of mutation classifications. The sample sizes were large enough for statistical testing in four groups with at least one mutation that completely abolishes enzyme activity. These patients are considered functionally hemizygous.

RESULTS

The biochemical phenotype predicted from the genotype in functionally hemizygous patients was related significantly to the assigned phenylalanine level. Cognitive performance (IQ) was also significantly related to genotype. The IQ of PAH-deficient mothers with a severe PKU mutation in combination with a MHP mutation or a mild PKU mutation was 99 and 96, respectively, whereas the IQ of PKU mothers with two severe PKU mutations or with one severe and one moderate PKU mutation was 83 and 84, respectively. Of the patients with PKU, 92% had been treated during childhood. Those who were untreated or treated late had lower than average IQ scores for their group of mutation combinations. Females with moderate or mild PKU who were treated early and treated for >6 years showed IQ scores 10 points above average for their group.

CONCLUSIONS

The reproductive outcome in maternal phenylketonuria is dependent on prenatal metabolic control and postnatal environmental circumstances. Both factors depend on the intellectual resources of the mother with PKU. The significant relationship among genotype, biochemical phenotype, and cognitive performance observed in the present study is of importance for the development of an optimal strategy for future treatment of females with PKU who plan pregnancy.

Genetics of autism: overview and new directions

Genetic epidemiology is the study of inherited factors involved in the etiology of a disease or disorder and uses the methods of both medical genetics and clinical epidemiology. In general, genetic epidemiology tries to answer the following four questions: Is the disorder inherited; What phenotype is inherited; How is it inherited or what is the mode of transmission; and What is the nature of the genetic mutation, if any, that gives rise to the disorder? The hope is that by identifying the gene or genes involved in pathophysiology, a much better understanding of the steps from gene product to phenotype will be possible, leading to improvements in diagnosis, an opportunity for thoughtful family planning, and perhaps, most important, to the development of treatments based on an understanding of the biochemistry of the disorder. We review the current knowledge of the genetic epidemiology of autism and the other pervasive developmental disorders (PDDs) and highlight promising new directions. There seems to be widespread agreement that the PDDs are caused, at least in part, by genetic factors. There is also some agreement on the phenotypic boundaries associated with these same genetic factors. However, many points of uncertainty remain, and several methodologic issues need to be resolved before further progress in mapping susceptibility genes is possible. We do not specifically review molecular studies, medical conditions associated with autism, or the broader autism phenotype, as these topics are covered in other papers in this special issue.

Infertility. A clinical guide for the internist

Infertility is a common condition that internists practicing primary care may increasingly encounter. Abnormal male semen parameters, ovulation disorders, and tubal dysfunction account for most cases of infertility. By performing a complete initial evaluation and through appropriate and timely referral, internists can contribute to the care and improve outcomes for couples with this condition (Table 9).

Maternal Phenylketonuria Collaborative Study (MPKUCS) offspring: facial anomalies, malformations, and early neurological sequelae

Maternal phenylketonuria (PKU) in untreated women has resulted in offspring with microcephaly, mental retardation, congenital heart disease (CHD), and intrauterine growth retardation. The Maternal Phenylketonuria Collaborative Study (MPKUCS) was designed to determine the effect of dietary control of blood phenylalanine (Phe) during pregnancy in preventing damage to the fetus associated with untreated Maternal PKU. A cohort of offspring from MPKUS pregnancies was ascertained and examined to evaluate malformations, including CHD, craniofacial abnormalities, microcephaly, intrauterine and postnatal growth retardation, other major and minor defects, and early abnormal neurological signs. For analysis, the women were grouped according to their mean Phe levels in mumol/liter, < or = 360, 361-600, 601-900, or > 900, during critical gestational weeks of 0-8 (N = 203) and 8-12 (N = 190), and average for Phe exposure throughout pregnancy (N = 183). Frequencies of congenital abnormalities increased with increasing maternal Phe levels. Significant relationships included average Phe 0-8 weeks and CHD (P = 0.001); average Phe 8-12 weeks and brain, fetal, and postnatal growth retardation (P < 0.0005 for all), wide nasal bridge (P < 0.0005), and anteverted nares (P = 0.001); and average Phe exposure during the entire pregnancy and neurological signs (P < 0.0005). Although 14% of infants had CHD, none of the CHD occurred at 120-360 mumol/liter and only one (3%) at 361-600 mumol/liter. At levels of 120-360 mumol/liter, there were three infants (6%) with microcephaly, two (4%) with postnatal growth, and none with intrauterine growth retardation, in contrast to 85%, 51%, and 26%, respectively, with Phe above 900 mumol/liter. These data support the concept that women with PKU should begin a low-phenylalanine diet to achieve Phe levels of < 360 mumol/liter prior to conception and should maintain this throughout pregnancy.

Social factors and the meaning of food in adherence to medical diets: results of a maternal phenylketonuria summer camp

A Maternal PKU camp provided education and social support for 25 young women with phenylketonuria (PKU). Questionnaires were administered and blood samples were collected on the first and last days of camp to evaluate the psychological and medical impact of the programme. Long-term outcome was assessed through telephone interviews 7-14 months later. Knowledge of maternal PKU and the maternal PKU diet increased significantly. There was a significant increase in campers' ratings of the degree to which others supported the use of birth control to prevent late-treated pregnancies, although campers' comfort with contraception did not change. Mean blood phenylalanine concentrations were significantly reduced by 37% during camp and by 20% at follow-up. Ninety-six per cent of campers remained in contact with other campers after the summer. At follow-up, one pregnancy was reported, in which metabolic control was achieved prior to conception. Overall, attitudes about treatment and perceptions about ability to cope with PKU did not change to a significant degree. It is suggested that camps may be most successful in changing both behaviour and attitudes if they actively involve the campers in food preparation, address the psychological meaning of food in our culture, and provide social support.

Clinical biochemistry of pregnancy

Major adaptations in maternal physiology and metabolism are required for successful pregnancy outcome. Hormonal changes initiated even before conception significantly alter maternal biochemistry early in pregnancy. Steroid hormones, peptide hormones, and prostaglandins interact to expand blood and plasma volume and modulate the maternal capacity to supply energy and nutrients to the fetoplacental unit. As gestation progresses, reference ranges for the concentration of many biochemical parameters change significantly from those found in the nonpregnant state. Gestation-specific reference ranges are essential for correct interpretation of tests used in screening, diagnosis, and monitoring during pregnancy. The use of clinical laboratory tests in the management of high-risk pregnancy are discussed from the perspective of testing before conception and during pregnancy.

Preconception genetic counseling

The purpose of this chapter has not been to be all-inclusive, but to raise awareness of the benefits of preconception consultation in the prevention of birth defects. If there is to be a significant decrease in the incidence of congenital malformations, it will come only by intervention that occurs prior to organogenesis, and that opportunity is lost by the first prenatal visit. For the practitioner interested in a more in-depth analysis of the subject of preconception counseling, the two books listed as supplementary reading provide a wealth of information essential to the care of the patient planning a pregnancy.

Maternal hyperphenylalaninaemia as a cause of microcephaly and mental retardation

We attempted to evaluate the role of maternal hyperphenylalaninaemia (HPA) as an isolated cause of mental retardation and microcephaly in children. This transversal study observed the plasma phenylalanine from mothers of 161 children with mental retardation and/or microcephaly of unknown origin. In this sample, we found two women with previously undiagnosed HPA, a frequency (2/161) higher than expected for our general population (1:12 500) (p < 0.001). We concluded that the plasma phenylalanine levels should be determined during preconceptional evaluation of every woman of reproductive age that already has had a child affected either by mental retardation or microcephaly of unknown cause. It is particularly significant where women currently having their pregnancies have not been screened for phenylketonuria as newborns, as happens in most developing countries.

German Maternal Phenylketonuria Study

The German maternal phenylketonuria (MPKU) Study began in 1989 and since 1992 works together with the American-Canadian MPKU Study. Main goals of the study are: (1) to find women with phenylketonuria (PKU) and mild untreated hyperphenylalaninaemia (HPA); (2) to inform them about the risks of an untreated pregnancy with PKU and HPA; (3) to evaluate the efficacy of the phenylalanine (Phe) restricted dietary treatment prior to and during pregnancy by following the physical and cognitive development of offspring from treated pregnancies. An interim report of the study is presented. Until now, 43 pregnancies have been followed. They resulted in 34 live births, 24 from women with PKU and 10 form women with HPA. There are significant negative correlations between the gestational age in which the dietary control (blood Phe level < 360 mumol/l) was reached and pregnancy outcome as measured by growth parameters and early cognitive and motor developmental quotients at the age of 2 years. For minimizing risks of MPKU, preconceptional dietary control is strongly recommended. Tracking and timely information of young women about risks of MPKU is of outmost importance.

Fetal ultrasonography in maternal PKU

Maternal phenylketonuria (PKU) is teratogenic and results in birth defects that include microcephaly, mental retardation, congenital heart disease, and intrauterine growth retardation. Treatment with a low phenylalanine diet can prevent or reduce the severity of the complications. Optimal benefit, however, requires frequent monitoring with fetal ultrasonography as a critical element. We have studied ultrasonography in 39 pregnancies enrolled in the Maternal PKU Collaborative Study and followed at our centre. First-trimester examinations in 24 pregnancies resulted in the discovery of non-viability in five. In each, this led to discontinuation of the difficult and expensive diet. Among the 33 pregnancies with second-trimester evaluation, congenital heart disease was identified in five. Two of these pregnancies were terminated. Microcephaly as determined by biparietal diameter (BPD) was identified in the second trimester in only one of nine fetuses who had microcephaly at birth. Among 20 pregnancies with third-trimester ultrasound, fetal microcephaly was identified by BPD in three of seven who had birth microcephaly. We conclude that fetal ultrasonography in maternal PKU is valuable during the first trimester in identifying non-viable pregnancies and determining gestational age and is also valuable during the second trimester in identifying congenital heart disease and perhaps other major anomalies, but not in identifying fetal microcephaly. Third-trimester ultrasound seems to be of limited usefulness.

The International Collaborative Study on maternal phenylketonuria: organization, study design and description of the sample

The International Maternal Phenylketonuria (PKU) Collaborative Study commenced in 1984 to evaluate the efficacy of the low-phenylalanine diet in reducing the morbidity associated with maternal PKU syndrome. Four hundred and sixty eight (468) pregnancies resulted in 331 live births, 3 stillbirths, 61 spontaneous abortions, 2 ectopic pregnancies and 71 elective terminations. Since its inception, the study has steadily progressed toward its goal of diet initiation preconception or early in pregnancy. By 1994, 51% of the sample began the diet preconceptionally, with an additional 41% doing so by 8 weeks gestation. The number of adolescent pregnancies has decreased from 31% to 9%, college attendance has increased from 5% to 16%, number of women in the lowest socioeconomic classes has decreased from 95% to 59% and average IQ has increased from 78 to 88. The organization of the network of 130 referral centers and clinics within the U.S.A., Canada and Germany and the objectives of the scientific research investigation have served to provide a derived benefit of outreach, education, reproductive counseling and early diet intervention in a large cohort of PKU women.

[Pregnancy and the child of a mother with phenylketonuria]

Pregnant women with hyperphenylalaninemia are at high risk of spontaneous abortion and of giving birth to infants with congenital malformations, microcephaly and mental defect. Among mothers whose phenylalaninemia is greater than 1200 mumol/L (20 mg/100 mL), 95% have at least one child with mental retardation. A low phenylalanine diet with a good control of phenylalaninemia, started before conception, reduces this risk, better results being obtained when plasma phenylalanine levels are maintained below 360 mumol/L (6 mg/100 mL) as compared with levels maintained between 360 to 600 mumol/L (6-10 mg/100 mL). Thus, systematic contraception and planned pregnancies must be recommended in all hyperphenylalanemic young women. This implies early information of phenylketonuric teenage girls and their parents. In addition, efforts must be made to join and inform all women having had hyperphenylalaninemia at birth, whether they received a dietary treatment or not. It is also important that general practitioners, pediatricians and obstetricians be aware of the high recurrence risk in hyperphenylalanemic women who gave birth to a microcephalic or malformed infant.

Maternal phenylketonuria: a metabolic teratogen

The maternal phenylketonuria (PKU) syndrome refers to the teratogenic effects of PKU during pregnancy. These effects include mental retardation, microcephaly, congenital heart disease, and intrauterine growth retardation. In untreated pregnancies wherein the mother has classic PKU with a blood phenylalanine level > or = 1,200 microM (20 mg/dl), the frequencies of these abnormalities in offspring are exceedingly high, approaching 75-90% for microcephaly and mental retardation and 15% for congenital heart disease. There is a dose response relationship with progressively lower frequencies of these abnormalities at lower phenylalanine levels, both in the pregnancies of women with variants of PKU and in treated classic PKU pregnancies. The pathogenesis of this syndrome is unknown; it may be related to inhibition by phenylalanine of large neutral amino acid transport across the placenta or to direct toxicity of phenylalanine and/or a phenylalanine metabolite in certain fetal organs. A mouse model for PKU now exists, and studies of maternal PKU in this model are in progress. The treatment of maternal PKU consists of biochemical control through a phenylalanine restricted diet during pregnancy. The best results are obtained with diet initiation before conception or no later than the earliest weeks of pregnancy. Women with PKU and their families require much psychosocial support to meet the strict requirements of a maternal PKU pregnancy, including compliance with a difficult diet. With such compliance, however, it seems that bearing normal or near normal offspring is possible.

Psychosocial factors in maternal phenylketonuria: women's adherence to medical recommendations

OBJECTIVES

This study identified factors predicting adherence to medical recommendations in maternal phenylketonuria, which can result in severe fetal damage.

METHODS

Sixty-nine women with phenylketonuria, 68 of their acquaintances, and 69 women with diabetes mellitus were interviewed annually for 5 years. A model in which each stage in the maternal phenylketonuria life cycle represented a treatment-related goal provided a means to assess adherence.

RESULTS

At the stages of prevention of unplanned pregnancy, treatment initiation, and diet continuation throughout pregnancy, attitudes and social support were associated with adherence to medical recommendations. No specific variables were associated with outcome at reproductive decision making, but women with phenylketonuria were more likely to delay making a decision, resulting in unplanned and, hence, untreated or late-treated pregnancy.

CONCLUSIONS

Women with phenylketonuria differed from their acquaintances and diabetic women in many respects, suggesting that special programs are needed. Greater emphasis on reproductive decision making is especially needed. Interventions that focus on improving social support networks and attitudes about treatment may increase adherence to recommendations.

Preconception care: a means of prevention

Preconceptional health promotion should provide a prevention framework for interactions with all women of childbearing potential. Preconceptional counselling is properly directed by specialists in the field of obstetrics and gynaecology, but a multispecialty effort may be needed to achieve adequate information for decision-making. Preconceptional health care offers an important opportunity for physicians involved in women's health to expand a primary care and a primary prevention focus. The obstetrician or gynaecologist is not only involved in acute diagnosis and treatment plans but also in disease prevention, risk and behaviour modification and counselling, which are integral parts of primary prevention and co-ordinated women's health care.

Maternal mild hyperphenylalaninaemia: an international survey of offspring outcome

Maternal phenylketonuria (PKU) has adverse effects on the offspring including microcephaly, mental retardation, congenital heart disease, and intrauterine growth retardation. Maternal non-PKU mild hyperphenylalaninaemia (MHP) is believed to be benign, but whether there may be long-term consequences to offspring is unclear. In an international survey we have obtained information about 86 mothers with MHP (blood phenylalanine 167-715 mumol/L), their 219 untreated pregnancies, and 173 offspring. Spontaneous fetal loss (13% of pregnancies), congenital heart disease (2.3% of offspring), and severe non-cardiac anomalies (2.9% of offspring) occurred at frequencies within expected limits for the general population. For weight and length at birth the median percentile was the 50th but that for birth head circumference was the 25th. Median z-scores for birth length and head circumference were significantly lower for offspring of mothers with phenylalanine concentrations above 400 mumol/L than for those whose mothers had lower values (p = 0.05 and p = 0.005, respectively). The median intelligence quotient (IQ) of the offspring (3-27 years) was 100 for those whose mothers had higher phenylalanine concentrations and 108 for those of the lower phenylalaninaemia group. However, offspring IQ correlated slightly more closely with maternal IQ (r = 0.53, p < 0.001) than with maternal phenylalanine concentration (r = 0.45, p = 0.02). Maternal MHP does not seem to have serious consequences for the fetus. A maternal phenylalanine concentration of less than 400 mumol/L does not warrant intervention. Nevertheless, maternal blood phenylalanine above this value is associated with slightly lower birth measurements and offspring IQ than lower maternal blood phenylalanine concentrations.

The international collaborative study of maternal phenylketonuria: status report 1994

Neonatal screening for phenylketonuria (PKU) has created a problem as females with PKU are reaching child-bearing age. Surveys have revealed that maternal phenylalanine blood concentrations greater than 1200 mumol/l are associated with fetal microcephaly, congenital heart defects and intrauterine growth retardation. It is estimated that as many as 3000 hyperphenylalaninemic females may be at risk of producing these fetal abnormalities. To examine this problem, the international maternal PKU collaborative study was developed to evaluate the efficacy of a phenylalanine-restricted diet in reducing fetal morbidity. Preliminary findings have indicated that phenylalanine restriction should begin before conception for females with PKU planning a pregnancy. Dietary control should maintain maternal blood phenylalanine levels between 120 and 360 mumol/l and should provide adequate energy, protein, vitamin and mineral intake. Pregnant hyperphenylalaninemic females who achieved metabolic control after conception or by the 10th week of pregnancy had a better offspring outcome than anticipated. The results of 402 pregnancies are reviewed.

Feto-maternal plasma phenylalanine concentration gradient from 19 weeks gestation to term

Plasma phenylalanine concentrations in fetal blood, obtained by cordocentesis, were compared with simultaneous peripheral venous plasma phenylalanine levels in mothers. The feto-maternal phenylalanine concentration ratio showed a gradual decrease from 19 weeks of gestation to term with an overall ratio of 1.35 +/- 0.42 (mean +/- S.D., n = 14).

Gestational carrier--a reproductive haven for offspring of mothers with phenylketonuria (PKU): an alternative therapy for maternal PKU

Maternal phenylketonuria, PKU, has a detrimental effect on embryogenesis. Infant pathology is independent of fetal genotype, but is directly correlated with excessive phenylalaninaemia throughout pregnancy. Although normal children have been delivered by affected mothers who either had benign hyperphenylalaninaemia or in whom strict diet has apparently maintained maternal phenylalaninaemia in the low normal range from before conception, more abnormal than normal births have been reported. In addition, attempts at dietary management are often unsuccessful; most reported cases documented various severe pathological consequences of maternal PKU. Currently available methods provide viable alternative treatment. In vitro fertilization using the parental gametes, followed by implantation of the pre-embryo in a surrogate mother, would avoid a metabolic environment impairing normal development, and therefore should be recommended as alternative therapy for potential mothers with PKU.