Twin to Twin

Twin pregnancies are generally well managed and result in two healthy babies. However, in a small minority of cases a potentially fatal complication called Twin to Twin Transfusion (TTTS) arises.

The gel feels cold on your stomach, the butterflies nervously flutter inside. It’s your first scan and you are naturally nervous.
‘Can you see that?’ asks the sonographer, pointing at two blinking dots on the screen.

‘Congratulations, you’re expecting twins.’

This life-changing news may come as a surprise, but shock soon morphs into excitement. With two babies on the way there is much to prepare for.

Generally, twin pregnancies are well managed and result in two healthy babies. However, in a small minority of cases a potentially serious complication called Twin to Twin Transfusion (TTTS) can arise.

Monozygotic, or identical twins, occur when a single sperm fertilises a single egg and that embryo splits. Dizygotic, or fraternal twins, are conceived when two eggs are separately fertilised.

Fraternal or dizygotic twins have their own placenta and are know as dichorionic. What confuses matters is that one third of identical twins also develop their own placentas.

But the risk occurs in the case of the other two thirds of identical twins who share a placenta, which means they are monochorionic.

Expectant parents usually learn by 12 weeks whether or not their twins share a placenta. These pregnancies should be closely monitored as a serious complication can arise which parents must be aware of. In most cases, there isn’t a cause for concern but if it does develop it can be life threatening for the babies.

What is Twin to Twin Transfusion?
According to The Multiple Births Foundation, the syndrome occurs in 10 to 15 per cent of monochorionic twin pregnancies. It is caused by abnormal blood vessels in the placenta connecting the blood supplies of both twins.

Usually an equal amount of blood flows from one twin to the other, but transfusion occurs when the flow is unbalanced. The baby who receives too little blood is known as the donor, the other the recipient.

Jane Denton, director of The Multiple Births Foundation, explains, “This causes the donor twin to have low blood pressure and low urine production, as well as signs of poor blood flow.”

“In contrast, the recipient twin receives too much blood, with a large blood flow through the baby’s kidneys causing the bladder to look enlarged and there’s also significantly increased amniotic fluid. In addition, this twin’s heart has to work harder to cope with the extra blood supply.”

How does TTTS affect the twins?
In milder cases both babies will be born healthy, although they may differ in size. The donor might be pale and anaemic, while the recipient is likely to be larger and very red due to excess blood. The recipient’s high level of haemoglobin may also cause jaundice.

In more severe cases the donor will produce little urine because of insufficient blood flow to the kidneys. Less amniotic fluid could lead to the donor becoming ‘wrapped’ within its own membranes.

Meanwhile the recipient produces large amounts of urine and therefore too much amniotic fluid. This baby’s heart could struggle to pump the extra blood around its system, which can ultimately lead to heart failure.

If severe TTTS goes untreated the babies’ chances of survival are poor. However, Ms Denton is keen to stress that while the condition is potentially very serious, it is relatively rare and can often be managed safely if diagnosed early enough.

What to look out for
Women carrying monochorionic twins should consult a doctor immediately if they experience:
✽ Increased thirst
✽ Premature contractions
✽ A sudden growth (sometimes overnight) of the abdomen
✽ Constant tightness and discomfort in the abdomen

What can be done?
A diagnosis of TTTS can be extremely worrying, but Ms Denton says: “Most importantly your pregnancy should be monitored and the recently published NICE Guideline should ensure that this is routine and where necessary you are referred to a fetal medicine centre.

“Once you are in the TTTS world you will meet many other people whose lives are spent dealing with it.

“They will be there for you, giving you advice and support in difficult and dangerous situations.

“There are solutions and you will be told exactly what your options are and what is best for you and your babies.”

However, Ms Denton stresses that, “all cases are individual and what’s right for one woman may not be for another”.

Case Study

After Nicki Lynch had her son Ben 12 years ago, she made herself a promise. Childbirth was not something she would go through again.

The pregnancy had passed smoothly, but her intensive labour resulted in considerable blood loss, many stitches and a prolapsed uterus.

Still, like many a woman traumatised by childbirth, the horror of Nicki’s experience faded with time. Then, five years ago, she and husband Gary decided to try for a second. Sadly, the couple from Friern Barnet, north London, suffered two miscarriages but in 2009 their fortunes changed.

“I went for a private scan at six weeks and we found out we were having identical twins. We were very excited – nervous, but excited,” says health club manager Nicki, 41.

The scan revealed that the twins were monochorionic, which meant they shared a placenta. As a result, Nicki and Gary were referred to a London hospital which specialises in multiple births.

Recalling her first check-up at 12 weeks, Nicki says, “They briefly told us about twin to twin transfusion, but in passing. There was nothing to indicate that that ours was a high-risk pregnancy.”

“We weren’t warned; we just came away feeling ours were healthy.”

The months passed without incident and Nicki blossomed.  As her due date approached she began shopping for her longed for daughters who she and Gary had already named Amelia and Kelsey.

Then at 30 weeks, a scan revealed a weight difference between the two.

“We were told there was a slight difference in weight but nothing to be concerned about and they advised us to come back a fortnight later for another scan.”

But ten days later Nicki’s waters broke at just 32 weeks. Gary called 999, but it took 45 minutes for an ambulance to arrive. In the meantime, a paramedic showed up.

“There was so much water and he asked me to lie down to try and stop the flow,” says Nicki.

“He was preparing to deliver the babies at home, but I knew something wasn’t right.”

When the paramedic called Nicki’s hospital, they said they were unable to send a midwife out. Eventually after a lengthy wait, the ambulance arrived to take Nicki to her local general hospital, where she was found to be bleeding.

“They listened for the heartbeats but one was very faint, so they decided to do an emergency caesarean,” Nicki says.
While his wife lay on the operating table under general anaesthetic, Gary stood in the corridor alone.

“I was scared and panicking about Nicki, especially after what happened with Ben,” says the 41-year-old gardener.

“The nurses were running in and out and nobody said anything to me. Then I saw a tiny baby come out in an incubator.”

“They rushed her off and it seemed I was waiting for ages again. Eventually the doctor came out and said, ‘I’m really sorry but we’ve had problems with the second one and she’s died’.

“They asked if I wanted to hold her, but I just stood there crying,” says Gary.

Five hours later Nicki awoke to a living nightmare.

“The minute I looked at Gary I knew something was badly wrong,” she says.

“I threw up everywhere and said I didn’t want to know.”

Staff eventually broke it to Nicki that Kelsey had died and Amelia was in intensive care, having undergone an emergency blood transfusion – as had Nicki herself.

“Although they weren’t completely sure, they said they thought it had been due to twin to twin transfusion,” says Nicki, fighting back the tears.

Overwhelmed with grief, Nicki eventually agreed to see Kelsey.

“We held her and took photos. She was the colour of the placenta and much bigger than Amelia. It was a real shock.”

A post-mortem examination later confirmed twin to twin transfusion had occurred. Losing a baby is always devastating, but what made matters so much worse was that this tragic outcome was preventable.

“If they had called me for a scan a week after the last one to check on the weight difference, I honestly believe they would have caught it,” says heartbroken Nicki.

“As far as we knew, they were both fine. I was never led to believe in any way that twin to twin could have been fatal to both of my babies.

I’ve since discovered that it’s actually quite rare for one to survive so we are completely blessed to have Amelia.”

Despite her traumatic birth and several weeks spent in special care, Amelia is now thriving and has just turned two.

“She’s unbelievable really and so precious to us,” says Nicki, who urges other expectant parents of twins to be vigilant.

She adds, “Do your research and push for regular scans. We don’t want other people to go through it.”

“It’s a condition that can be picked up and Kelsey didn’t have to die because of it.” ✿

TTTS Facts:


Mild cases can stabilize or remedy themselves. If they remain stable but amniotic fluid is excessive, it is possible to drain some through a procedure called amnio-reduction.

Fetoscopic Laser Ablation Therapy
The preferred treatment in more severe cases before 26 weeks gestation. A tiny telescope is inserted into the woman’s uterus. The shared blood vessels can then be sealed to prevent further transfusion. This is the best treatment currently available and both babies survive in 60 – 70% of cases.
Selective Feticide

If TTTS occurs very early on or is not cured by laser therapy doctors may suggest selective feticide. This is a last resort option that involves saving one twin instead of risking the lives of both.

After 26 weeks

If both babies are of a viable weight doctors may decide to induce delivery and treat the twins

For more information The Multiple Births Foundation offers detailed guidance about TTTS call 020 3313 3519 or go online