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When you’ve just delivered your baby – especially after a long labour that ends in an emergency C-section – the very last thing on your mind is your next pregnancy. You’re focused on recovery, feeding, nappies and soaking up those newborn cuddles.
But research from Tommy’s suggests that for some women who have a C-section late in labour, there may be an increased risk of preterm birth in a future pregnancy.
The reassuring news? With the right monitoring and, in some cases, a procedure called a cervical stitch, or cervical cerclage – many of these early births can be prevented.
Professor Anna David, Professor of Obstetrics and Maternal Fetal Medicine at University College London and Deputy Director of Tommy’s National Centre for Preterm Birth Research, says awareness of this risk is growing within maternity care.
“We now recognise that if you have a full dilatation caesarean section, you do have an increased risk of preterm birth in a subsequent pregnancy,” she explains.
Here’s what you need to know – in plain English – and why it matters.
Why can a late C-section affect a future pregnancy?
During labour, your cervix (the neck of the womb) gradually softens, thins and opens to 10cm to allow your baby to be born. If a C-section happens when you are fully dilated – or close to it – the baby’s head is usually very low in the pelvis.
To deliver the baby safely, the surgeon makes an incision in the lower part of the womb. When labour is advanced, that incision can sit very low – sometimes close to, or even involving, the cervix itself.
Professor David explains that: "If you have a caesarean section when your cervix is more dilated, you have a lower scar on your womb. So if you have a caesarean section at 4 centimetres, your scar is much higher up, more likely to be in the womb, and extremely unlikely to be in the cervix compared to if you have a caesarean section when you're 8, 9 or 10 centimetres."
If the cervix is weakened or scarred, it may shorten earlier in the next pregnancy. A shortening cervix can increase the likelihood of spontaneously having a preterm birth – defined as delivery before 37 weeks. Professor David cites research which looked at the risk of spontaneous preterm birth after women had a caesarean section at various stages of cervix dilatation in labour. They found that if you had a caesarean section when around 3cm dilated, your chance of having a preterm birth was about 2 per cent. At 10cm, the risk of preterm birth was around about 15 percent. To put that into context, if you have a vaginal birth without any caesarean section, the chance of preterm birth in the next pregnancy is around 5 or 6 per cent.
It’s important to stress that in some scenarios c-sections are the only option, but like any surgery, there can be longer-term consequences that are only now being fully understood. "If you need one, you need one. They're life saving procedures and they can save the mum and the baby's life. But of course, every surgery has consequences. And we are now learning much more about what those consequences are."
What does the NHS recommend?
Under the NHS Saving Babies’ Lives Care Bundle, women who have had a full dilatation (10cm) C-section are recommended to have additional monitoring in their next pregnancy.
This usually means a transvaginal cervical length ultrasound between 16 and 20 weeks. This quick internal ultrasound measures how long the cervix is. A shortening cervix can be an early sign that preterm birth may happen.
If the cervix is found to be short, treatment may be offered. This could include vaginal progesterone or a cervical stitch (also known as a cerclage).
If you’ve had a late-stage C-section and are pregnant again, your midwife or GP should refer you for this monitoring. If it hasn’t been mentioned, you are absolutely within your rights to ask.
What is a cervical stitch?
A cervical stitch is exactly what it sounds like – a strong stitch placed within and around the cervix to help keep it closed during pregnancy.
The cervix normally stays firm and closed until late pregnancy. In some women, particularly those with cervical weakness or scarring, it can begin to shorten and open too early, sometimes without pain or obvious symptoms.
“A cervical stitch is basically designed to reinforce the cervix.” Professor David explains. “The stitch essentially closes up the cervix, makes the mucus plug in the cervix canal stay put and prevents the bacteria from getting in.”
The procedure is usually inserted under regional (spinal) or general anaesthetic, and most women go home the same day. Most stitches are typically removed at around 36–37 weeks, allowing labour to start naturally.
Naomi’s story: ‘It felt like we were finally doing something’
For Naomi, awareness came too late in her second pregnancy.
Her first birth, with daughter Amira, ended in an emergency C-section after labour stalled.
“At the time, my only concern was making sure my daughter arrived safely,” she says. “I trusted the medical team and was grateful when she was born healthy. I had no reason to think that birth experience might have implications for future pregnancies.”
She wasn’t told that the stage of labour at her C-section might affect future pregnancies.
It was only after losing her twins at 21 weeks that she began to learn about cervical insufficiency and the possible link with previous Caesarean births.
“At 19 weeks pregnant with my twins, I went to hospital because I was in pain and knew something didn’t feel right. I was examined and told my cervix was closed. I was reassured and sent home.
“A short time later, an internal scan showed my cervix had significantly shortened and was funneling (opening from the top). It was devastating.”
In her subsequent triplet pregnancy, Naomi received specialist care, including regular cervical length scans and a cervical stitch.
“Being told I might need a cervical stitch was a mixture of fear and relief,” she says. “Fear because I had already lost my twins. But relief because, for the first time, it felt like there was something proactive we could do.”
She delivered her triplets at 33 weeks and five days.
“When you’ve lost babies at 21 weeks, every week beyond that point feels significant. Every extra day was a gift.”
Are there risks?
A cervical stitch is generally considered safe when offered to the right women. As with any procedure, there are small risks, including bleeding, infection or triggering contractions, but serious complications are uncommon.
Success rates are reassuring. Many women who have a stitch go on to deliver much later in pregnancy, particularly when it is placed before the cervix becomes very short. Professor David notes, "We do about 120 cervix stitches a year at UCLH. Around three quarters of the women that we put a stitch in, deliver at term. Around about one quarter deliver preterm but mostly this is close to preterm."
The most important message: ask questions
For mums who may be considering another baby, this information can feel overwhelming. But knowledge is empowering – not frightening.
If you’ve had a late labour emergency C-section and are planning another pregnancy, speak to your GP or midwife before you conceive if possible. Make sure your previous birth details are clearly documented. Ask whether you would qualify for cervical length monitoring.
And if you’re pregnant and something doesn’t feel right – persistent pelvic pressure, unusual discharge, or just a gut instinct – trust yourself and ask to be checked.
As Naomi says: “If sharing my story encourages even one woman to ask for monitoring or receive an intervention that helps save her baby’s life, then it’s worth it.”
Preterm birth can’t always be prevented but careful monitoring, asking the right questions, and getting the right intervention at the right time can make all the difference.
And for many families, those extra weeks can mean everything.
About the author
Rebecca Lancaster is a Digital Writer for Mother&Baby, drawing on eleven years of parenting her two children to help others navigate their own parenting journey. As a freelance writer, she spent ten years working with leading lifestyle brands, from travel companies to food and drink start-ups, and writing everything from hotel reviews to guides to the best British cheeses. She’s particularly interested in travel and introducing her children to the excitement of visiting new places, trying different foods (less successfully) and experiencing different cultures.
