Current pregnancy outcomes in women with cystic fibrosis

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Abstract

Objectives

Women with cystic fibrosis (CF) now achieve a greater life expectancy and therefore have greater expectations from life. Literature reporting pregnancy outcomes in CF is still sparse. There remains a legacy of advising women with significant disease to avoid pregnancy. We aimed to assess current maternal and fetal outcomes in women with CF with varied pre-pregnancy lung function.

Study design

Retrospective case note review of data from 15 pregnancies in 12 women with CF receiving care at a specialist centre between 2003 and 2011. Descriptive statistics were used for the quantitative data. The forced expiratory volume (FEV1) and forced vital capacity (FVC) were calculated and shown as the percentage of their predicted values for BMI, height and age. Changes in lung function pre, 6, and 24 months post delivery were calculated with the paired t-test.

Results

Mean maternal age was 28.9 (range 21–36, CI 26.8–31). Maternal FEV1 at booking ranged from 27 to 80% predicted (mean = 63.6%, CI 54.62–71.38%). Cystic fibrosis-related diabetes (CFRD) was present in 8 of 14 (live birth) pregnancies. Average gestation at delivery was 38 weeks. There was a 100% vaginal delivery rate (11 spontaneous vertex, 2 ventouse, 1 forceps). Average fetal birth weight was 2.97 kg (range 2.2–3.83 kg, CI 2.72–3.23). The differences between the maternal pre- and 6 months post-pregnancy mean FEV1 (p = 0.136) and FVC (p = 0.225) were not statistically significant.

Conclusion

With careful multidisciplinary antenatal and intrapartum management, successful outcomes have been obtained in this group of women with CF.

Introduction

Cystic fibrosis (CF) is a common inherited autosomal recessive disorder, with a gene prevalence of 1 in 25. The gene defect, located on chromosome 7, leads to abnormalities of the cystic fibrosis transmembrane chloride channel in epithelial cells, resulting in viscous secretions in glandular organs. The condition is characterised in the lungs by viscous mucus, which becomes chronically colonised with various organisms leading to recurrent respiratory infections. Following this, chronic inflammation leads to progressive bronchiectasis, and therefore declining respiratory function and eventually respiratory failure leading to death. Bowel, pancreatic and hepatobiliary organs are also affected, resulting in impaired digestion, reduced absorption, steatorrhoea and malnutrition in which the condition may be further complicated by diabetes mellitus and biliary cirrhosis.

It is advised that all patients with CF are managed primarily or in conjunction with specialist CF centres, with chest physiotherapy, nutritional supplements, pancreatic enzymes, mucolytics, long-term oral and nebulised antibiotics and frequent courses of intravenous antibiotics [1].

Survival with CF has dramatically improved over the last decade, due to the optimisation of the respiratory system and nutrition. Around 50% of women with CF can now expect to live to over 38 years of age [2]. Earlier suggestions of reduced female fertility in CF have been shown to be unsubstantiated [3]. In one study the F508del homozygote mutation was shown to be less common suggesting heterozygotes for F508del and other mutations reflect milder disease and those patients are more likely to survive and become pregnant [4]. The median age at diagnosis of CF in women who become pregnant has also been reported to be significantly lower than that of non-pregnant women.

With increased life expectations, more women with CF wish to conceive; thus the number of pregnancies in women with CF as recorded by the Cystic Fibrosis Foundation is increasing rapidly [5]. Since the improvement in life expectancy, the published pregnancy outcome data are limited; therefore, pre-pregnancy counselling advice at present may not be current. CF in pregnancy was previously thought to be associated with high rates of premature delivery, stillbirth and miscarriage [6]. Recent evidence suggests however, that the percentage of live births is 83.1%, and the spontaneous miscarriage and prematurity rates may now be comparable to that of the general population [7]. Poor lung function at conception has been thought to be the most predictive factor in determining pregnancy outcome [6], [8]. A review of pregnancy outcomes of women with CF from 1977 to 1996 in the UK concluded that pregnancy should be avoided if FEV1 < 50–60% or if cor pulmonale or pulmonary hypertension are present [8]. Other studies have supported these recommendations [3], [7], [9], [10], [11]. A recent study of 20 pregnancies also concluded that a reduced FEV1 and low BMI were significant predictors of fetal complications [12].

Moreover pregnancy does not affect long-term survival: indeed there is evidence that the 10-year survival rate is higher for women with CF who become pregnant; even in women with poor lung function (forced expiratory volume, FEV1 < 40%) [13], [14]. Our study aimed to assess outcomes of all cases of CF in pregnancy in our unit over the last eight years with a wide range of pre-pregnancy lung function.

Section snippets

Materials and methods

We performed a retrospective review of maternal and fetal outcomes on all cases of CF during pregnancy at University Hospitals, Bristol, between January 2003 and January 2011. The hospital is a specialist centre for CF. All cases were identified from both respiratory and obstetric records.

Care in pregnancy was provided by a multidisciplinary team consisting of a CF respiratory physician, an obstetrician in maternal medicine, CF dietitians, a CF physiotherapist, CF nurses, CF psychologists, a CF

Results

During the study period from January 2003 to January 2011, there were 15 pregnancies identified in 12 women. Thirty-three per cent (5/15) had pre-pregnancy counselling.

The outcomes of all 15 pregnancies were known including 14 live births (93.3%), 12 (86%) at term (>37 weeks). There were no stillbirths, neonatal deaths or early maternal deaths. One fetal anomaly was identified (acrania at 14 weeks gestation) and a surgical termination of pregnancy was performed. This patient went on to have a

Comment

Pregnancy in women with CF is increasingly common, and the incidence will continue to rise as the health of the CF population continues to improve. Approximately 30–40 women with CF will undertake pregnancy each year in the UK [2]. Most complications for the fetus are thought to be related to prematurity and, for the mother, to deteriorating lung function and nutrition [15]. Our small case series has shown a 100% vaginal delivery rate, with low prematurity rates, birth centiles between the 3rd

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