WS06.04Cystic fibrosis and pregnancy: the impact of modulator therapy

Abstract

Objectives

With the increased number of pregnacies seen in Patients With Cystic Fibrosis (pwCF) following the introduciton of Highly Effective Modulator Therapy (HEMT) the aim of our study was to look at outcomes at a single, large tertiary CF centre for women going through pregnancy with CF, to identify whether there were significant differences following the introduction of HEMT with a particular note looking at pregnancies defined as high risk (with an FEV1 <60%).

Methods

Retrospective non-controlled study looking at pwCF who had a pregnancy between 2010 and 2023.

We reviewed electronic notes for patients at Liverpool Heart and Chest (LHCH) for miscarriage being recorded in notes. We reviewed notes from LHCH and Liverpool Women's Hospital (LWH) for demographic information and respiratory, obstetric and neonatal outcomes for pwCF who had a livebirth outcome.

Results

We identified a total of 66 pregnancies over the period 2010 to 2023 for analysis; nineteen miscarriages and forty-seven livebirths.

Outcome	Non-HEMT (n= 27)	HEMT (n=39)
Miscarriage Rate	33% (9/27)	25% (10/39)
In Vitro Fertilisation	39% (7)	7% (2)
Pre-Pregnancy FEV1	78% (range 45-97%)	73% (range 31-105%)
Pregnancy FEV1	78% (range 36-97%)	72% (range 39-117%)
Post Pregnancy FEV1	77% (range 36-99%)	74% (range 36-122%)
Average change in FEV1 %	+0.4% (range –12% to +13%)	-0.9% (range –23 to +12)
Change FEV1% post pregnancy	-1.5% (range –23 to +11%)	+0.8% (range –18 to +14)
High Risk Pregnancies (FEV1 <60%)	13% (2)	25% (8)
Average Gestation at Delivery	37.51 weeks	36.89 weeks
Number of Preterm Deliveries	28% (5)	40% (10)
C-Sections	34% (6)	68% (17)
-Elective	17% (3)	48% (12)
-Emergency	17% (3)	20% (5)
Vaginal Deliveries	67% (12)	32% (8)
SCBU Admission	41% (7)	34% (8)
Birthweight	2966g (1620-3850g)	2851g (1155-3880g)

While the number of women experiencing exacerbations in pregnancy was similar between groups, women in the HEMT group had fewer exacerbations and required fewer weeks of antibiotic treatment. The most common indications for C-section or induction was cystic fibrosis and respiratory decline/ chest infection.

Outcome	Non-high-risk Pregnancy on HEMT (FEV1% >60%) (n=21)	High-risk Pregnancy on HEMT (FEV1% <60%) (n=8)
Pre-Pregnancy FEV1	81% average (Range 60%-104%)	48% (Range 31-58%)
Post-Pregnancy FEV1	81% average (Range 42%-122%)	48% (Range 36-61%)
Miscarriage Rate	19% (5)	38% (5)
Gestation at Delivery	37.3 weeks (range 34+4 -41+3 weeks)	35.73 weeks (range 27+6 to 38+5)
Method of Delivery
LSCS	65% (11/17)	75% (6/8)
NVD	35% (6/17)	25% (2/8)

Conclusion

With the introduction of HEMT the number of pwCF undergoing pregnancy has increased. With this it is important to look at how HEMT may have impacted outcomes in pregnancy for pwCF. This study whilst small numbers adds to the body of evidence available for pre-conception counselling and possible pregnancy outcomes for pwCF on HEMT and particularly those considered higher risk.

Given the increase in spontaneous conceptions likely demonstrating an improvement in fertility on HEMT, this also highlights the importance of including discussions about contraception as part of standard CF care.