Successful term pregnancy following cervical cerclage for uterine atrophy secondary to childhood radiotherapy

Abstract

Pelvic radiotherapy can lead to scarring and atrophy of reproductive organs including the uterus. This may lead to complications, such as preterm birth, during pregnancy. The mechanism by which preterm birth is associated with pelvic radiation is believed to be due to inefficient uterine stretch or a deficient cervix. We report a case of cervical shortening during the second trimester in a pregnant woman with a history of pelvic radiotherapy in childhood. Ultrasound surveillance and cervical cerclage inserted in the shortening cervix successfully prevented preterm labour in this case. Cerclage insertion led to a longer cervix and lower fibronectin. Although cervical cerclage does not influence uterine stretch, it may be able to prevent cervical dilatation and therefore prevent ascending infections and subsequent inflammatory sequelae which results in preterm labour. We recommend cervical surveillance and targeted cerclage interventions to prevent preterm labour in women with prior childhood pelvic radiotherapy.

Background

Some of the lasting effects of radiation include scarring and atrophy of organs. In the case of pelvic radiotherapy, the uterus may be affected causing uterine atrophy.¹ A number of cohort studies have shown a link between pelvic radiotherapy and preterm birth.^{2 3} It is unknown if enhancing cervical integrity with a cerclage could reduce this risk as the mechanism of preterm birth is unclear.⁴ We report a case in which cervical cerclage successfully prevented preterm birth in a woman with uterine atrophy secondary to childhood radiotherapy of the pelvis.

Case presentation

We describe a case of a woman in her 30s in her first pregnancy who had a medical history of chemoradiotherapy to the pelvis. She was referred to the preterm surveillance clinic due to uterine atrophy secondary to pelvic irradiation as there was concern that the reduced uterine capacity and distension may cause preterm labour.

At the age of 2, our patient was diagnosed with alveolar rhabdomyosarcoma of the pelvis which had spread into the inguinal lymph nodes, requiring both chemotherapy and pelvic radiotherapy. Multiple treatments of external beam radiation therapy were undertaken to a total dose of 5840 cGy. She later developed significant complications including hip dysplasia, bladder scarring and vaginal stenosis. In 2011 and 2013, she underwent surgery for vaginal introitus widening and removal of scar tissue, and she also received physiotherapy at the age of 21.

Ultrasound surveillance was instigated at the preterm surveillance clinic at a large tertiary obstetric unit in London. As the pelvic radiotherapy had caused significant vaginal stenosis, there was significant concern about uterine atrophy which may affect the ability of the uterus to distend and hold a pregnancy to term.

Investigations

The preterm surveillance clinic measured serial cervical lengths and fetal fibronectin levels throughout the second trimester, where miscarriage risk is highest. At 14⁺⁶ weeks’ gestation, the average cervical length is measured at 19 mm, and a cervical length below 25 mm is considered short at this gestation. The cervix also felt deficient on examination, consistent with atrophy. The patient had weekly transvaginal scan surveillance, with a plan to insert a cervical cerclage should the cervix shorten further. At 19⁺⁶ weeks’ gestation, she presented with a 5 mm cervix with a cervicovaginal fetal fibronectin level of 33 ng/mL. Cervicovaginal fetal fibronectin is a glycoprotein that is widely used to predict preterm labour with levels below 10 ng/mL being associated with low risk of preterm birth.

Treatment

A McDonald cervical cerclage with an ethilon suture was inserted the following day. Following cerclage placement, weekly scans demonstrated cervical length ranging from 11 to 14 mm and with normal fibronectin levels <10 ng/mL. An obstetric growth scan performed at 35⁺⁶ weeks’ gestation showed a reduction in fetal growth with a raised umbilical artery perfusion index above the 95th centile with positive end-diastolic flow, suggesting placental insufficiency. In view of the scan findings and an episode of reduced fetal movements, an emergency caesarean section at 36⁺¹ weeks of gestation was performed. The decision to perform a caesarean section, rather than an induction of labour, was due to the vaginal stenosis.

Outcome and follow-up

The caesarean section was uncomplicated, and the estimated blood loss was 700 mL. The baby was born in good condition, weighing 2310 g, in the 25th centile with Apgar scores of 9 and 10. The baby did not require admission to the neonatal unit, and they were both discharged home on postnatal day 3 with no complications.

Discussion

Irradiated uteri have been shown to have an atrophic myometrium, impaired blood flow and small uterine volume and length.^{1 5 6} The pelvic radiotherapy described above resulted in significant scarring, reflected by the irreversible vaginal stenosis and shortening, and it is likely that nearby and associated organs such as the uterus were affected. The deficient cervix in early pregnancy was consistent with this.

The risk of miscarriage and preterm delivery is high following pelvic radiotherapy.⁷ These outcomes are more common if prepubertal radiation took place, such as in the case of our patient.^{3 8} The mechanism of preterm birth is uncertain but is thought to be related to uterine stretch inducing cervical shortening which leads to increased risk of ascending vaginal infection and subsequent inflammation resulting in premature labour or due to reduced intrauterine capacity. Cervical cerclage has been regularly used as an intervention to prevent preterm birth in high-risk patients. Its use in this cohort has not been described before.

A rising cervicovaginal fetal fibronectin level is associated with a shortening cervix and risk of ascending infection and allowed us to discriminate when an already short cervix (due to the scarring secondary to radiotherapy) requires intervention.⁹ Fetal fibronectin measurements have been described to be useful in evaluating preterm labour in the setting of cervical cerclage.^10–12 Cervical change may be related either to uterine stretch or a deficient cervix, but either mechanism can be influenced by cerclage. Cerclage insertion prevented further cervical shortening and lower cervicovaginal fibronectin level in this case. Although cervical cerclage does not influence uterine stretch, it may be able to prevent cervical dilatation and therefore prevent ascending infections and its subsequent inflammatory sequelae.¹³

Patient’s perspective.

I have very few memories of having cancer or the treatments because I was so young, so the majority of my cancer experience has been through the late effects. It was disheartening; as I grew up I found out more things were wrong with my body, and none of the symptoms were glamorous!

Before I hit puberty I was told that my fertility might have been affected. I was young, and parked that worry, but it was good to have the warning. However, as there were no overt signs that my vagina was scarred, and I did not know what was normal, so there was no warning for that. It was a slow realisation on my part that something was wrong, and I sought help. However, I am still unable to have penetrative sex.

When we talked about having a family, together with the fertility question and the vaginal scarring, it seemed like bad odds. I asked my GP to for a referral so I could discuss trying to get pregnant. They said I had a good chance at getting pregnant, confirming what I’d been told previously: that I would need a caesarean section. Soon after I had uterine fibroids removed and sent on my way.

To my surprise I got pregnant on my second or third cycle. We had to be creative to overcome the physical limitations, so I thought that I had summited the biggest obstacle.

My medical history has taught me to be cautious. At my first phone appointment I was booked to see an obstetrician mid-second trimester because of my history. But on my first physical appointment my BP readings were high, and I had to be seen by an obstetrician on the day. The obstetrician ran through the BP issues and fibroids. I had come with some of my original radiotherapy and chemo treatment notes including the diagram of my field of radiation and on seeing those he asked me to return the next day.

I learnt the risks of preterm labour with my history, and found out that my cervix was extremely short. It certainly took the wind out of my sails. After getting through the first trimester I thought I was quite safe. Sharing the news of being pregnant became a lot less exciting and more complicated. A terrible bout of urine retention shortly after, and having a catheter for a week compounded the bad mood! Cervical measurements were a constant reminder of the risk to my baby and me, but simultaneously I felt incredibly well looked after by the staff and the science. I both looked forward to, and dreaded, Wednesdays. Time dragged by but we tried hard to look forward. We found out the sex of our baby, and my partner came to the 20 week scan– the first scan he could attend due to Covid. He had to leave before my cervical measurement – the measurement which showed that my cervix had shortened drastically; I could see the funnelling on the screen and the baby’s feet tapping against my cervix. Half a centimetre seemed horribly short. I’d known from the day of my booking appointment that I may end up with a cervical stitch, yet I was still shocked in the moment.

I came back the next day for the procedure, which was physically pretty easy; mentally it was very hard, especially being in hospital with the sounds of the maternity ward around me. I was home the next day and I kept myself as mentally busy/distracted as you can during a pandemic. A few days later we went into a lockdown again until after the end of my pregnancy.

But I ‘got out’ once a week to preterm clinic. Seeing familiar faces there each week was extremely comforting, as was the chance to see my baby on the monitor. I was pleased to have access to the Quipp app; I appreciated seeing data on the likelihood of going into labour, though I understood my exact circumstances were not necessarily reflected in that data, being quite specific. But it was something to focus on. By the time we passed 30 w, with a good run of FFN and discharge from preterm clinic, things felt much easier, even with the growth scan worries and potentially complex Caesarean. As it was, the baby did wonderfully after birth, and the surgery turned out to be straightforward. After everything, it was utterly overwhelming and amazing when the baby arrived. The baby is the best thing that has ever happened to us, and we are so thankful.

I had numerous interactions with medical professionals during my pregnancy, birth, and aftercare. Most were simple, professional, predictable. Some were more awkward and stressful; the wards and clinics are busy and you don’t always know what is going on, as the patient. It’s remarkable how many, even some fleeting ones, left indelible impressions. The whole experience of having a baby is so highly charged, that some small moments and certain faces have stayed with me, they felt very poignant. I particularly noticed the level of communication between the obstetricians managing my and my baby’s care; their eye for detail was impressive. I also appreciated the patience and care they had when listening to me and answering my questions. Thank you to all of them.

Learning points.

• Ultrasound surveillance and cervical cerclage inserted in the shortening cervix successfully prevented preterm labour in an atrophic uterus secondary to pelvic irradiation.

• Cervical cerclage insertion prevented further cervical shortening and lower cervicovaginal fibronectin levels in an atrophic uterus.

• We recommend cervical surveillance and targeted cerclage interventions to prevent preterm labour in women with prior childhood pelvic radiotherapy.

Ethics statements

Patient consent for publication

Consent obtained directly from patient(s).