A vaginal birth after caesarean (known as a VBAC) is when a woman who has had a caesarean has a vaginal birth down the track.

In Australia, about 12% of women have a vaginal birth for a subsequent baby after a caesarean. A VBAC is much more common in some other countries, including in several Scandinavian ones, where 45-55% of women have one.

So what’s involved? What are the risks? And who’s most likely to give birth vaginally the next time round?

What happens? What are the risks?

When a woman chooses a VBAC she is cared for much like she would during a planned vaginal birth.

However, an induction of labour is avoided as much as possible, due to the slightly increased risk of the caesarean scar opening up (known as uterine rupture). This is because the medication used in inductions can stimulate strong contractions that put a greater strain on the scar.

In fact, one of the main reasons women may be recommended to have a repeat caesarean over a vaginal birth is due to an increased chance of her caesarean scar rupturing.

This is when layers of the uterus (womb) separate and an emergency caesarean is needed to deliver the baby and repair the uterus.

Uterine rupture is rare. It occurs in about 0.2-0.7% of women with a history of a previous caesarean. A uterine rupture can also happen without a previous caesarean, but this is even rarer.

However, uterine rupture is a medical emergency. A large European study found 13% of babies died after a uterine rupture and 10% of women needed to have their uterus removed.

The risk of uterine rupture increases if women have what’s known as complicated or classical caesarean scars, and for women who have had more than two previous caesareans.

Most care providers recommend you avoid getting pregnant again for around 12 months after a caesarean, to allow full healing of the scar and to reduce the risk of the scar rupturing.

National guidelines recommend women attempt a VBAC in hospital in case emergency care is needed after uterine rupture.

During a VBAC, recommendations are for closer monitoring of the baby’s heart rate and vigilance for abnormal pain that could indicate a rupture is happening.

If labour is not progressing, a caesarean would then usually be advised.

Why avoid multiple caesareans?

There are also risks with repeat caesareans. These include slower recovery, increased risks of the placenta growing abnormally in subsequent pregnancies (placenta accreta), or low in front of the cervix (placenta praevia), and being readmitted to hospital for infection.

Women reported birth trauma and post-traumatic stress more commonly after a caesarean than a vaginal birth, especially if the caesarean was not planned.

Women who had a traumatic caesarean or disrespectful care in their previous birth may choose a VBAC to prevent re-traumatisation and to try to regain control over their birth.

We looked at what happened to women

The most common reason for a caesarean section in Australia is a repeat caesarean. Our new research looked at what this means for VBAC.

We analysed data about 172,000 low-risk women who gave birth for the first time in New South Wales between 2001 and 2016.

We found women who had an initial spontaneous vaginal birth had a 91.3% chance of having subsequent vaginal births. However, if they had a caesarean, their probability of having a VBAC was 4.6% after an elective caesarean and 9% after an emergency one.

We also confirmed what national data and previous studies have shown – there are lower VBAC rates (meaning higher rates of repeat caesareans) in private hospitals compared to public hospitals.

We found the probability of subsequent elective caesarean births was higher in private hospitals (84.9%) compared to public hospitals (76.9%).

Our study did not specifically address why this might be the case. However, we know that in private hospitals women access private obstetric care and experience higher caesarean rates overall.

What increases the chance of success?

When women plan a VBAC there is a 60-80% chance of having a vaginal birth in the next birth.

The success rates are higher for women who are younger, have a lower body mass index, have had a previous vaginal birth, give birth in a home-like environment or with midwife-led care.

For instance, an Australian study found women who accessed continuity of care with a midwife were more likely to have a successful VBAC compared to having no continuity of care and seeing different care providers each time.

An Australian national survey we conducted found having continuity of care with a midwife when planning a VBAC can increase women’s sense of control and confidence, increase their chance to be upright and active in labour and result in a better relationship with their health-care provider.

Why is this important?

With the rise of caesareans globally, including in Australia, it is more important than ever to value vaginal birth and support women to have a VBAC if this is what they choose.

Our research is also a reminder that how a woman gives birth the first time greatly influences how she gives birth after that. For too many women, this can lead to multiple caesareans, not all of them needed.

Hannah Dahlen, Professor of Midwifery, Associate Dean Research and HDR, Midwifery Discipline Leader, Western Sydney University; Hazel Keedle, Senior Lecturer of Midwifery, Western Sydney University, and Lilian Peters, Adjunct Research Fellow, Western Sydney University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

So, you got your eyesight tested and found out you need your first pair of glasses. Or you found out you need a stronger pair than the ones you have. You put them on and everything looks crystal clear. But after a few weeks things look blurrier without them than they did before your eye test. What’s going on?

Some people start to wear spectacles for the first time and perceive their vision is “bad” when they take their glasses off. They incorrectly interpret this as the glasses making their vision worse. Fear of this might make them less likely to wear their glasses.

But what they are noticing is how much better the world appears through the glasses. They become less tolerant of a blurry world when they remove them.

Here are some other things you might notice about eyesight and wearing glasses.

Lazy eyes?

Some people sense an increasing reliance on glasses and wonder if their eyes have become “lazy”.

Our eyes work in much the same way as an auto-focus camera. A flexible lens inside each eye is controlled by muscles that let us focus on objects in the distance (such as a footy scoreboard) by relaxing the muscle to flatten the lens. When the muscle contracts it makes the lens steeper and more powerful to see things that are much closer to us (such as a text message).

From the age of about 40, the lens in our eye progressively hardens and loses its ability to change shape. Gradually, we lose our capacity to focus on near objects. This is called “presbyopia” and at the moment there are no treatments for this lens hardening.

Optometrists correct this with prescription glasses that take the load of your natural lens. The lenses allow you to see those up-close images clearly by providing extra refractive power.

Once we are used to seeing clearly, our tolerance for blurry vision will be lower and we will reach for the glasses to see well again.

The wrong glasses?

Wearing old glasses, the wrong prescription (or even someone else’s glasses) won’t allow you to see as well as possible for day-to-day tasks. It could also cause eyestrain and headaches.

Incorrectly prescribed or dispensed prescription glasses can lead to vision impairment in children as their visual system is still in development.

But it is more common for kids to develop long-term vision problems as a result of not wearing glasses when they need them.

By the time children are about 10–12 years of age, wearing incorrect spectacles is less likely to cause their eyes to become lazy or damage vision in the long term, but it is likely to result in blurry or uncomfortable vision during daily wear.

Registered optometrists in Australia are trained to assess refractive error (whether the eye focuses light into the retina) as well as the different aspects of ocular function (including how the eyes work together, change focus, move around to see objects). All of these help us see clearly and comfortably.

What about dirty glasses?

Dirty or scratched glasses can give you the impression your vision is worse than it actually is. Just like a window, the dirtier your glasses are, the more difficult it is to see clearly through them. Cleaning glasses regularly with a microfibre lens cloth will help.

While dirty glasses are not commonly associated with eye infections, some research suggests dirty glasses can harbour bacteria with the remote but theoretical potential to cause eye infection.

To ensure best possible vision, people who wear prescription glasses every day should clean their lenses at least every morning and twice a day where required. Cleaning frames with alcohol wipes can reduce bacterial contamination by 96% – but care should be taken as alcohol can damage some frames, depending on what they are made of.

When should I get my eyes checked?

Regular eye exams, starting just before school age, are important for ocular health. Most prescriptions for corrective glasses expire within two years and contact lens prescriptions often expire after a year. So you’ll need an eye check for a new pair every year or so.

Kids with ocular conditions such as progressive myopia (short-sightedness), strabismus (poor eye alignment), or amblyopia (reduced vision in one eye) will need checks at least every year, but likely more often. Likewise, people over 65 or who have known eye conditions, such as glaucoma, will be recommended more frequent checks.

An online prescription estimator is no substitute for a full eye examination. If you have a valid prescription then you can order glasses online, but you miss out on the ability to check the fit of the frame or to have them adjusted properly. This is particularly important for multifocal lenses where even a millimetre or two of misalignment can cause uncomfortable or blurry vision.

Conditions such as diabetes or high blood pressure, can affect the eyes so regular eye checks can also help flag broader health issues. The vast majority of eye conditions can be treated if caught early, highlighting the importance of regular preventative care.

James Andrew Armitage, Professor of Optometry and Course Director, Deakin University and Nick Hockley, Lecturer in Optometric Clinical Skills, Director Deakin Collaborative Eye Care Clinic, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.